Page 1 of 2 12 LastLast
Results 1 to 60 of 72

Thread: Some canoe rigs

  1. #1
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Some canoe rigs

    My wife and I are in Cedar Key Florida for a month. I can get bored on these trips so I brought a canoe and most of the fixings to assemble some different rigs.

    The first, which I will report in installments, will be about converting an Optimist dinghy sprit sail to a balanced lug. The idea came from a suggestion by New Zealand boat designer John Welford on Dylan Winter's blog about West Mersea Duck Punts, which are virtually canoes.

    The duck punters use the sails with sprits. A sprit sail can be a bit hard to manage in a canoe, esp. if you sit in a low and somewhat fixed seat. A balanced lug, on the other hand, is easily managed.

    One of the attractions about these sails is that they can be cheap, as little as $90 US (or astronomically expensive). They are about 35 sq feet and the cheap ones are competently made in Asia out of 4 ounce polyester. At these prices they are not class legal, but that is no matter for us for canoes.

    Here are the steps:

    1. A planning and design phase, making measurements.

    2. Making a new 'yard' to replace the function of the sprit.

    3. Making a sleeve to fit to the head of the sail. It will hold the yard and also supply a little extra sail area. One could do this with grommets but that is more costly if you need to buy grommet tools. Also if the sleeve is removed, nothing has changed about the sail save some small holes from zig-zag stitches.

    4. Tuning mast and sleeve to each other.

    5. Making a boom (but I have one).

    6. Working up halyard, downhaul and sheet.

    7. Testing, etc.

    Stay tuned to this station for more....
    Last edited by Bob Cavenagh; 14th-March-2017 at 12:45 AM.

  2. #2
    Join Date
    Dec 2006
    Location
    Just a little to the right of the Shire
    Posts
    2,803

    Default

    Hey Bob, sounds interesting. Looking forward to more instalments
    Cheers
    Tim


    Paddles a Prospector

  3. #3

    Default

    Very interested too Bob. I am currently outfitting a Snake River 12 canoe and am planning to add a small sail. I have an Optimist rig which I think is a little too large so am considering using an Optimist Trisail which is half the size and bermudan in layout. It should easily reef down to an even smaller size if needed. I have thought about converting the Optimist sprit rig to a Lug setup in the past for another canoe but never got round to it. Looking forward to seeing how you get on.
    Regards
    Chris

  4. #4
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default About this project

    I hope to get some photos parked online and ready to link by tomorrow. In the meantime, some general comments on this project:

    I brought an older aluminum Grumman 15 with me as the stalking horse for three different sail rigs. This particular hull has two 'mast step tabs' installed and I will be making a third (they are no longer available from Grumman). I have brought a rather minimal tool kit on the trip so this will challenge my improv skills.

    Once the new step is made and installed I will add three mast thwarts at different locations, allowing me to choose the location best suited to each sail. I also brought a factory standard leeboard thwart, designed for two boards--but I only plan to use one, a modified Sunfish daggerboard. At that point I will work out rigging for each. I have a factory rudder with the curved metal piece that attaches it to the stern, and a long pole for a push-pull steering arrangement.

    I will target each installment at the novices on the site--if you are an old hand, skim ahead.

    I know some folks are down on aluminum canoes. Only a few of the things I will describe are generic to those, or to Grummans in particular. I have kind of grown up with these hulls, like them, and they serve some particular needs well: I can leave them outside all winter in Canada, and they are well suited to the shallow waters and sharp oyster beds here at Cedar Key.

    Cedar Key Florida is an interesting place. An old and fairly basic fishing town on the middle west coast of the state with a population of about 800--- plus a couple thousand tourists and temporary residents and a few shops and restaurants catering to them. It is nothing like the posh beachy places like Miami, etc. It is surrounded by wildlife sanctuaries, with hundreds of different birds and critters. We have rented a waterfront condo (apartment, flat, etc.). I can leave the canoe on the small beach below us and be off to explore parts of the Gulf of Mexico. "Laid back" barely begins to describe it. Until I get some of my own images linked, here are a few from the web:









    Every May there is a small boat and canoe messabout, which I always miss:

    Last edited by Bob Cavenagh; 15th-March-2017 at 12:56 AM.

  5. #5
    Join Date
    Sep 2014
    Location
    Cumbria
    Posts
    1,681

    Default

    Watching with interest.

    I'm trying something similar with a cut-down miracle jibsail, although it currently resembles more of an unbalanced jug.
    "I'm not getting in a boat which is DESIGNED to go upside down."

  6. #6
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    An unbalanced JUG---hmmm-----half empty???

    More seriously, I looks kind of like a square rig set as a standing lug.I have spent time playing with square rigs and they are interesting. But you sail seems to have a great deal of camber just behind the leading edge (near the mast). No problem while going downwind as I presume you are doing in the photo, but that can make upwind performance difficult. Do you have some way to flatten it at those times?

    Bob

    Quote Originally Posted by stinkwheel View Post
    Watching with interest.

    I'm trying something similar with a cut-down miracle jibsail, although it currently resembles more of an unbalanced jug.

  7. #7
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Measurements and planning

    My interest in converting an Opti sail into a balanced lug for a canoe is related to the shape of those sails. Let's start by looking at an Opti (Optimist Pram or Dinghy). They can be rather lively little boats. You can find lots more pictures on the web:





    Here is a pretty basic intro to sail parts. It will help us establish vocabulary we will need later.




    The sail is attached to the mast, which holds it in shape. The head (ie: the top) of the sail it held up by a sprit. Tension on the sprit is controlled by what those Opti folks call a sprit halyard, but which is traditionally called a snotter. (I guess the word snotter is too risable for the young folks who sail these boats.) The amount of tension on the sprit determines how flat or baggy the upper part of the sail is at that time. For upwind work it needs to be rather flat. The luff (the front edge of the sail) and the angled head both help develop thrust going upwind, and they work best when the sail behind them doesn't have much curvature.

    The boom is lashed to the foot (the bottom of the sail), which is rather curved, as you will see a bit further along. The bottom front corner of the sail (the tack) is fastened to the front of the boom. The rear end of the boom is tied to the clew (the bottom rear corner of the sail), and an adjustment to that line (the clew outhaul) helps regulate the shape of that curve: tighter=flatter.

    The boom vang (or kicking strap, or kicker) is a tackle that serves to pull the boom down. Doing so helps to control sail shape.

    The main sheet is the primary control of sail position. Pulled in tightly, the sail moves near the centerline of the hull for upwind work. Eased out, the sail moves away from the hull for sailing across the wind (or reaching), or for sailing downwind.

    (The official sail plan for these boats can be found here: http://www.optimist.hu/files/szabalyok/sailplan.pdf)

    Here is are measured drawings in mm and inches. The approximate CE is marked with a red dot.:



    You will notice that a dimension is given for the 'leech' (the rear edge of the sail) but that the sail actually extends beyond that measurement area. This sail uses two battens, basically flat sticks sewn into the real after edge of the sail. They support that edge to keep it from flapping and losing shape. The area beyond the leech arrow is traditionally called a roach. The true leech is the absolute rear of the sail, beyond the roach. The Opti class sail plans use complex measurements to describe the officially allowed sail shape. For our purposes we merely need some approximate measurements.

    Notice also that there is a curved area in the foot, beneath the foot measurement arrow. This is often called foot round, but it is also a kind of roach. That curved area is attached to the boom; doing so produces a significant rounded area in the lower part of the sail.

    Some boat classes measure these extended areas carefully; in other cases it is considered free area and is used by crafty sailmakers to make a sail larger than its nominal dimensions. (Modern sailmakers have many techniques for creating particular sail shapes. Modern sails are never quite flat; the individual cloth panels have quite subtle shapes.)

    >>>>The red dot representing the CE or Center of Effort is a close approximation. There are ways of measuring that point quite exactly but this will be close enough for our purposes. I simply eyeballed it into place, and it may be a smidgen too high. We will want to know that approximate location when we decide where to place the mast of our canoe, and also the leeboards. These sails are almost symmetrical. If I decide that I need to add points for reefing (reducing sail area), that fact will allow the CE to stay near the same fore-and-aft position.<<<<


    For my experiment, I will set up the sail quite differently. This picture from the web shows the layout of a balanced lug sail. A yard will replace the sprit, and part of the sail will protrude in front of the mast. The halyard is a line that will raise and lower the sail, while the downhaul is an arrangement of blocks (pulleys) and rope that will pull the foot of the sail down hard, applying considerable tension the the luff to keep it straight and taut for upwind work.



    These sails seem ripe for conversion to lugs:

    My Opti sail has a straight luff with a few tiny grommets to allow it to be attached to a mast. That straight luff will be great as I will be able to tension it for upwind sailing.

    The head of this sail is also cut quite straight so the sprit can hold it taut. Since I plan to replace the sprit with a yard, I will need some way to attach it. I am making a cloth sleeve that will be sewn to the head of the sail. Yards work a bit differently than sprits, and I will want to have some options for putting just a little more shape into the revised head of my sail. Those things will become clearer when I show the yard and sleeve construction.

    This is probably enough for one installment. Next time: making a yard.

    My best,

    Bob
    Last edited by Bob Cavenagh; 16th-March-2017 at 02:00 AM.

  8. #8
    Join Date
    Sep 2014
    Location
    Cumbria
    Posts
    1,681

    Default

    Quote Originally Posted by Bob Cavenagh View Post
    An unbalanced JUG---hmmm-----half empty???

    More seriously, I looks kind of like a square rig set as a standing lug.I have spent time playing with square rigs and they are interesting. But you sail seems to have a great deal of camber just behind the leading edge (near the mast). No problem while going downwind as I presume you are doing in the photo, but that can make upwind performance difficult. Do you have some way to flatten it at those times?

    Bob
    In short, yes, it's got a cable running through the luff. I don't currently have the halyard attached directly to the yard, it's attached to a bit of rope on either end for now. If I attach the halyard directly to the yard and pull it tight, it'll be paralell to the mast. In honesty, it was going a bit fast for my comfort in my picture above (About 10km/h over ground on my GPS) so putting more tension in the sail seemed a) Tricky to juggle and b) Risky. In short, it was sailing me.

    I don't want to hijack your thread but I suppose it's somewhat relevant. Here's a better picture of what I've done. I probably need to change how and where I attach it to the mast which is why I'll be taking a particular interest in what you do. I suspect I need to attach the yard directly to the mast pretty much directly below where I have the halyard attached currently. I've not fully decided how I'm going to do that yet.

    I don't want to cut the enormous mast down yet until I've decided where everything is going, I was using a pico jib sail as a downwind one before which needed all that length.

    As I say, watching with interest to use your ideas. The sail I've cut down there was 6.50 on ebay so it's not a huge loss if I've wrecked it. I also have another one.

    Here's that picture of what I did. It's a pretty big image, if you right click and "view image", you'll seee more detail.
    "I'm not getting in a boat which is DESIGNED to go upside down."

  9. #9
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    That sail doesn't seem terribly large to me.

    The line you have tied to the ends of the boom might be called a lift or bridle. The end attachment points allow the middle of the sail to sag, and the halyard attachment point at the middle of the lift is putting a somewhat excessive pull on the aft end of the sail, which is, I believe, why you have the diagonal crease (or girt) that is clearly visible.

    If you want to configure the sail as a lug, you will want to attach the halyard 1/3 to 1/2 of the way from the front of the sail.

    With the front of the boom attached to the mast, you have a 'standing lug' sail. Attach the boom to the mast somewhat further aft and it will become a balanced lug. Google those two sail types for lots more info.

    Your yard appears very straight, as it would with a lift or bridle set as you have done. An ideal yard will bend a bit--see my next installment.

    There appears to be some hollow curvature in the luff of your sail. See if you can pull that taut to reduce draft in the front part of the sail. Jibs are often cut with a shallow 'S' curve in their luffs to help keep them flat. If you had cut this sail from the upper portion of your jib, that bit of hollow might have been part of the sail's original cut., but I don't think that is the case here.

    If you want to make some experiments without cutting the head of the sail for an attachment point, you could try using a c-clamp (g-cramp??) around the sail and tying the halyard to that. I would NOT do a lot of actual sailing rigged that way, but alongshore it may be informative.

    Bob


    [/QUOTE]

  10. #10
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Making a yard, with some 'social' digression

    We will look quickly at making a yard to replace the sprit, but first

    Some "social" content:

    Cedar Key Florida can be a zany place, with a wide range of folks showing up for different reasons. How about a Pirate Wedding?



    Tonight my wife dragged me to 'Steamers,' an oyster and clam/beer etc. bar with roadhouse overtones (what is a roadhouse equivalent in the UK??) They had a 'bluegrass' band that mostly played 50'-70's rock with bluegrass styling.



    Lots of older folks, a mixed crew from posh to long beards and ball caps. One woman kept standing up to dance, and when the band played Rocky Top about 10 other women joined her.



    I shot a bit of video, but enough is enough!



    The yard of a lug sail plays some important roles. It supports of the top of the sail, and it also helps control sail shape. The ideal yard will be stiff but somewhat flexible. When the sail is tensioned lightly by the downhaul, the yard is fairly straight. When the sailor tightens the downhaul, the leech and luff pull ends of the yard down and it becomes slightly bow shaped. This pulls out the curvature in the top of the sail, making it flatter. At the same time, the front end of the yard keeps the luff of the sail tight. And when a strong gust comes along, the yard should have some reserve flexibility to let it sag to leeward, depowering the top of the sail.

    The flexing properties of the yard are, ideally, coordinated with the shape of the head of the sail. Sailmakers often have to guess at the properties of the yard for a sail they are making, but I have the advantage of being able to control both.

    For this project, I want a yard that tapers to each end and is fatter in the middle. I'll measure its bend by supporting it at both ends and fastening a weight to its middle that equals in pounds about half the sail's area in square feet. I want it to be strong but light. My work on the yard will be a bit interactive with my work of the sail sleeve, but here is my start:

    I need a yard about 48+ inches long, so I chose a piece of wood that is about 54 inches. The wood I am using here is call Parana Pine and came from Home Depot, a large US DIY chain. It has straight, clear grain, is relatively soft but not weak and works easily. I began with a piece 1 1/2 inches square, used my table saw to rip it down to 1 1/4" square. Then I ran it over a router table with a 1/2" roundover bit. The result was a rounded stick with 1/4 inch flat surfaces on each side.

    Here is a similar, slightly larger piece I worked up in the same way:



    I brought the stick with me to Cedar Key, went to work tapering its ends with a small but sharp block plane:



    The right end shows the original shape, while the left end shows a square shape--I tapered each side from the middle of the stick to the end, then turned it around and worked up the other end. When I finished, the ends were about 1 inch square. I then used the plane to ease the edges back into a round shape. Note the clamp and wood block on the left side that acts as a 'stop' to keep my work from slipping. There are lots of other ways of doing this shaping but this worked with my tools at hand.

    This was a rather pleasant task that took about 20 minutes. This is really a tough, unpleasant working environment

    When I finished, I took the stick inside, set it across the back of two chairs with a little baggage scale and my tool bucket suspended from the middle.




    I then added and subtracted tools until I was close to 17.5 pounds (the sail is 35 sq ft).



    I measured how much the yard deflected when I added the weight: about 3/4-7/8 inch. I then stopped. I can always go back and take off more wood if necessary. I'll leave it unfinished for now.


    Next project: inventing and making my sleeve.

    My best,

    Bob

  11. #11
    Join Date
    Jun 2016
    Location
    Eagles Nest Lakes, Ely, Northeastern Minnesota, USA
    Posts
    94

    Default

    Hi Bob, it looks like you're having a nice vacation. It is snowing where I am in northern Minnesota, so seeing open water and sails makes me a little envious. Thank you for taking the time and effort to post this thread. As a newbie to sailing I'll need to study it more before much sinks in.
    SB

  12. #12
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Quote Originally Posted by silverbear View Post
    Hi Bob, it looks like you're having a nice vacation. It is snowing where I am in northern Minnesota, so seeing open water and sails makes me a little envious. Thank you for taking the time and effort to post this thread. As a newbie to sailing I'll need to study it more before much sinks in.
    SB

    Thanks,Silverbear.

    There are a bunch of Minnesotans here. Wonder why???

  13. #13
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Making the sleeve

    I have finished the sleeve. A whole bunch of photos will illustrate.

    I began with a piece of sailcloth 1 foot by about 66 inches. The cloth is similar to that of the sail. For starters, I laid it out on the kitchen counter:



    I planned to fold the cloth in half lengthways after adding some reinforcement. Note that the left edge is doubled over for that reason, and that there are some reinforcing patches laid out. I cut the cloth with the tip of the little soldering iron, cutting against a metal 'cookie sheet' pan.

    I want to make two reinforced windows for attaching the halyard and a parrel. You can see them marked out by x shapes here:



    Here is the folded end:



    I will also add the patch seen in that photo; the end will be sewn shut as a sort of socket for the upper end of the yard and it will need to take some thrust.

    I then cut open my windows and folded the edges inward:



    Next step: fasten everything in place with double sided sailmakers' 'Seamstick' tape:



    The tape will hold things together while I sew and adds a little strength. I recommend buying the professional stuff for this job. I have tried other alternatives, like double stick Scotch tape, and they have issues.

    The tape has a paper backing that is easy to peel once you get it started, but that can be a pain. I have learned to lift an end with a knife point or needle:



    Next step: sewing the patches, etc. in place. I dragged a heavy old machine and two folding tables with me on the trip so I don't have to work on the floor.




    Here is what the openings look like from the inside:



    And the outside:



    Not a perfect job, but not too shabby either. It should work. I have never made a sleeve before. I have repaired several, and the design of this one is just a guess at what should work.


    Here is the upper end of the sleeve. I sewed a little piece of light line into the crease. I will use that to attach a pennant or streamer.



    Here I have folded the sleeve over and sewn a curved straight stitch line from one end to the other and about 1 inch from the edge of the sleeve. The curve is about 1 7/8 inch deeper in the middle than at the ends. I trimmed off excess cloth beyond that 1 inch band. The one inch band will overlap the head of the sail when I sew everything together.




    The ends of this sail are rather heavily reinforced, despite its small size. A strong line is also sewn into the head to keep it from stretching. There are 12 layers of cloth at certain points here, which will prove tough for my sewing machine.



    The other end of the sail is similarly reinforced. I found it easy to sew the entire length of sleeve and head EXCEPT for the last couple of inches at each end. I did a crude job there that will hold for now, but when I get home I will beef up my stitching.




    And now --taadaah--a test hoisting. Wrong rigging, wrong mast, wrong thwart and step, but it served its purpose! I am pretty happy!




    The yard is a bit too stiff and the boom is much too stiff, but those can be fixed. The sail set better once I added a parrel at the top. In use, the bottom of the sail will be rocked rearward and the downhaul attached nearer the front of the boom. We had about 7 knots of wind when I took those shots. I moved the sail to different angles to the wind. It developed useful power. I probably will do a little tweaking on the sleeve attachment, but for now I am well satisfied.

    I will have to go sailing to see how well the rig points. 35 sq. ft. is not a lot of sail area, but should be enough to potter around nicely.

    I have other things to do before I can sail the canoe: a mast step to make, rigging for three different sails to add, etc. I will continue to post on my progress on those, too. One of the sails is a Balogh (BSD) 36 footer that will require the very tall mast, the other is a Grumman standard lateen.



    As Bugs put it: "That's all for now, folks!"

    And Happy St Patrick's...

    Bob

  14. #14
    Join Date
    May 2007
    Location
    Deepest darkest Wales
    Posts
    3,997

    Default

    No images visible...
    This post may vanish at any moment.

  15. #15
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Quote Originally Posted by DougR View Post
    No images visible...

    Everything opens on my Android and Windows 10 laptop. All but the last installment open on my wife's iPad.
    I posted everything the same way, so I don't have a solution but will work on it.

    Ideas anyone????

    Other experiences​?
    Last edited by Bob Cavenagh; 18th-March-2017 at 01:01 PM.

  16. #16
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    After some experimenting, it seems that all the previous posts open on different browsers, but the last segment only opens images on Google's Chrome browser (if you have that, try it and let me know). I posted everything the same way and all the images have similar addresses. When I send a photo address directly to Firefox or the new MS Edge browser, it opens right up. Strange.

    I will keep working on this.

    Bob

  17. #17
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Here is a new version of one of the disfunctional images. If it works, then I suspect there is an issue with sharing being enabled on my Google Photos site. Life was easier with Picasa.





    Quote Originally Posted by Bob Cavenagh View Post
    After some experimenting, it seems that all the previous posts open on different browsers, but the last segment only opens images on Google's Chrome browser (if you have that, try it and let me know). I posted everything the same way and all the images have similar addresses. When I send a photo address directly to Firefox or the new MS Edge browser, it opens right up. Strange.

    I will keep working on this.

    Bob

  18. #18
    Join Date
    Aug 2009
    Location
    Eastern England
    Posts
    1,186

    Default

    That last worked for me.

  19. #19
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Great. I think I know how to proceed. It will take me a while to sit down and repost.

    Bob

  20. #20
    Join Date
    Jun 2016
    Location
    Eagles Nest Lakes, Ely, Northeastern Minnesota, USA
    Posts
    94

    Default

    Using windows 7 on my laptop I could not see the images in question. I'm looking now on a chromebook and can see the image of you with canoe on the beach... the one you just posted, but not the ones missing on the windows 7 laptop. Picassa was nice. Haven't yet tried google photos. Just looked on the windows 7 machine and the last photo you posted with canoe & sail on the beach is posted. You got it figured out...
    SB
    Last edited by silverbear; 18th-March-2017 at 02:36 PM.

  21. #21
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Quote Originally Posted by silverbear View Post
    Using windows 7 on my laptop I could not see the images in question. I'm looking now on a chromebook and can see the image of you with canoe on the beach... the one you just posted, but not the ones missing on the windows 7 laptop. Picassa was nice. Haven't yet tried google photos. Just looked on the windows 7 machine and the last photo you posted with canoe & sail on the beach is posted. You got it figured out...
    SB
    I think the issues is indeed the permissions option in Google Photos. I could see my own photos because I was logged into Google. Others were blocked because they weren't listed on my shared account. But there is a separate (and nearly identical) image portal that allows sharing. When I posted from there the images turned up.

    That is not me in the photo, by the way. It is one of the Minnesotans who stopped by to check my progress.

    Bob

  22. #22
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Repost of Making the sleeve, with some image tweaks

    I am dividing this repost into a couple of sections for testing purposes. There were issues with 'permissions' in Google Photos last time. We shall see....

    I have finished the sleeve. A whole bunch of photos will illustrate.

    I began with a piece of sailcloth 1 foot by about 66 inches. The cloth is similar to that of the sail. For starters, I laid it out on the kitchen counter:



    I planned to fold the cloth in half lengthwise after adding some reinforcement. Note that the left edge is doubled over for that reason, and that there are some reinforcing patches laid out. I cut the cloth with the tip of the little soldering iron, cutting against a metal 'cookie sheet' pan.

    I want to make two reinforced windows for attaching the halyard and a parrel. You can see them marked out by x shapes here:



    Here is the upper end that will be folded over as a 'stop' for the yard:



    I will also add the patch seen in that photo; the end will be sewn shut as a sort of socket for the upper end of the yard and it will need to take some thrust.

    I then cut open my windows and folded the edges inward:



    Next step: fasten everything in place with double sided sailmakers' 'Seamstick' tape:




    The tape will hold things together while I sew and adds a little strength. I recommend buying the professional stuff for this job. I have tried other alternatives, like double stick Scotch tape, and they have issues.

    The tape has a paper backing that is easy to peel once you get it started, but that can be a pain. I have learned to lift an end with a knife point or needle:



    Next step: sewing the patches, etc. in place. I dragged a heavy old machine and two folding tables with me on the trip so I don't have to work on the floor.




    I am going to stop here and post these images to see if they work. Let me know....

    Bob

  23. #23
    Join Date
    Nov 2007
    Location
    very soon to be norfolk
    Posts
    1,608

    Default

    I see 'em

  24. #24
    Join Date
    Sep 2014
    Location
    Cumbria
    Posts
    1,681

    Default

    A wee tip, because the same thing has happened to me with images on a post before.

    If you click "reply with quote" to your original post, you can remove the [quote] tags and just paste the relevant new image location in.

    Can save a fair bit of typing and mental investment.

    And yes, I can see your last lot of images.
    "I'm not getting in a boat which is DESIGNED to go upside down."

  25. #25
    Join Date
    May 2007
    Location
    Deepest darkest Wales
    Posts
    3,997

    Default

    Everything after post #13 working nicely - I guess you're right about the share permissions from Google Photos.

    Keep it coming.
    This post may vanish at any moment.

  26. #26
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Back again, hopefully with good images.

    With sewing completed, here is what the openings look like from the inside:



    And the outside:



    Not a perfect job, but not too shabby either. It should work. I have never made a sleeve before. I have repaired several, and the design of this one is just a guess at what should work.


    Here is the upper end of the sleeve. I sewed a little piece of light line into the crease. I will use that to attach a pennant or streamer. Similarly, I sewed a pair of lines to the lower end to tie to a hole in the other tip of the yard. My next step is to fold the sleeve in half and sew a shallow curve to provide a little more cloth in the middle of the head of the sail.



    You can see the curved line of straight stitches here. It is about 1 inch from the edge of the sleeve. I made the curve about 1 7/8 inch deeper in the middle than at the ends. I trimmed off excess cloth beyond that 1 inch band. The one inch band will overlap the head of the sail when I sew everything together.




    The ends of this sail are rather heavily reinforced, despite its small size. A strong line is also sewn into the head to keep it from stretching. There are 12 layers of cloth at certain points here, which will prove tough for my sewing machine.



    The other end of the sail is similarly reinforced. I found it easy to sew the entire length of sleeve and head EXCEPT for the last couple of inches at each end. I did a crude job there that will hold for now, but when I get home I will beef up my stitching.




    I guess I need to make a couple more photos: I have sewn the sleeve to the top of the sail. I should show that.


    Instead I got anxious to test the thing and now --taadaah--a test hoisting. Wrong rigging, wrong mast, wrong thwart, but it served its purpose! I am pretty happy!



    One of the neighbors is holding the sail in position for its first portrait.





    I learned a lot from this shot. The yard is a bit too stiff and the boom is much too stiff, but those can be fixed. The sail set better once I added a parrel at the top, keeping it close to the mast. In use, the bottom of the sail will be pulled rearward and the downhaul attached nearer the front of the boom. We had about 7 knots of wind when I took these photos. I moved the sail to different angles to the wind. It developed useful power. I probably will do a little tweaking on the sleeve attachment, but for now I am well satisfied.

    It may be hard to see, but the ties at the lower end of the sleeve go through the hole in the yard and then through the grommet in the original sail. Tightening or loosening the sleeve to yard part of the line determines how snug the yard is in the sleeve. Tightening the yard to grommet portion controls yard-grommet spacing and can reduce stress on the sleeve.

    The six little white fittings along the luff of the sail are screwed through six very small grommets. Called 'slugs', they ride in a grooved track in the mast that came with the sail. I will remove them before sailing.

    This sail has grommets along the foot to attach it to the boom. Because the current boom is so stiff, it won't flex to pull out some of the curvature in the foot, resulting in the crease seen here. A lighter and more flexible boom will do well.

    Conversely, if the sail was only attached at tack and clew ('loose footed'), the stiff boom would be just right.

    I will have to go sailing to see how well the rig points. 35 sq. ft. is not a lot of sail area, but should be enough to potter around nicely.

    I made this adaption using a sleeve because it makes minimal changes to the sail. It is also possible to add a bit of reinforcement to the head, then add several grommets to connect the sail to the yard. But those would be permanent changes.

    I have other things to do before I can sail the canoe: a mast thwart to make, rigging for three different sails to add, etc. I will continue to post on my progress on those, too. One of the sails is a Balogh (BSD) 36 footer that will require the very tall mast, the other is a Grumman standard lateen. Stay tuned.



    As Bugs put it: "That's all for now, folks!"


    Bob[/QUOTE]
    Last edited by Bob Cavenagh; 19th-March-2017 at 12:40 AM.

  27. #27
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Setting up a rig

    Old hands, please remember all this detail is for the benefit of novices.

    After finishing with the Opti sail I set up two others. Lets compare; here is the 35 sq ft Opti:



    Next, a Balogh at 36 sq feet.



    And an old Grumman lateen at 45 sq ft:



    Dirty and patched, the old lateen is nevertheless in good shape.

    Each has a different configuration and CEs (mathematical Centers of Effort) are in different places. Here are the same three sails but I have added a perpendicular to the approximate CE of each:



    All three CEs fall between the second mast step and the cross thwart in the middle of the canoe. The Grumman is perhaps the most forward and the Balogh is clearly the most rearward, not surprising since all that sail area is aft of the mast. If I rock the Opti sail a bit to the rear, its CE will also move to the rear. If I want to move those CEs elsewhere I will have to invent new steps and thwarts/partners.

    Note also the relative heights of each CE, the Balogh clearly being the highest. The higher the CE, the more heeling effect the sail is likely to produce, all else being equal.

    For a double ender like this canoe, it would be nice to have the CE dead center fore-and-aft, but we will make use of the current positions.

    It would also be nice to have the leeboard dead center, and have the weight of the canoe, crew, and all other objects balanced at that point. VERY hard to achieve...

    I have come to believe the setup of a rig should have 6 elements, some more obvious than others. They are:

    1. Hull balance.

    2. Setup of sail, rigging, and gear

    3. Positioning of leeboard or other lateral plane

    4. Steering: rudder or paddle, chiefly.

    5. Comfort and convenience of the crew.

    6. Careful planning for safety.

    All of these elements interact; the last two sometimes come up short in published instructions, but they are very important.

    Hull balance also often gets little mention, so lets start there:

    Hull Balance

    Any boat is intended to 'sail on its lines,' meaning the waterline shown in plans by its designer. Canoes are light, and sail rigs themselves are light (I just weighed all three of these, including sail, masts and spars, and they ranged from 7.5 to 11 pounds. (This weight is delivered to the hull via the mast, so the lateen's weight is further forward.)

    A leeboard and a rudder (if used) add some weight and/or possibly some buoyancy, depending on construction.

    In general the largest weight in any sailing canoe is that of the crew, which is almost always greater than that of the hull and perhaps everything else. Therefore figuring out where to place crew weight is a matter of real concern. A single sailor usually sits amidships, more or less.

    It might seem is if getting the hull perfectly balanced so that it 'sits its lines' at a dock would be the ideal thing. NOT QUITE! We actually want the bow of the canoe to be a bit higher than the stern when the boat is at rest. The force of the wind acts well above deck level; whatever force is pushing the canoe FORWARD is also pushing the bow downward, and the higher the CE is, the more of this downward force is created. As noted, the tall and rather skinny Balogh sail has its CE considerably higher than the other two. When wind and weight are perfectly adjusted, the canoe bow is depressed down to it's designed position. (And as the wind picks up, the sailor typically moves to the rear to counteract the increased downward force of the sail.)

    If this phenomenon isn't clear, let me know and I'll try to explain further. Or make a little model: a block of wood to represent the hull with a tall dowel for a mast somewhat forward of center, and see what happens as you push the thing forward along the floor from different points on the dowel. A physicist might explain it as a 'couple,' or a displaced force.

    For a solo canoe, we try to position the sailor so his/her weight is just a bit aft of the middle. Fortunately, double ended hulls are slightly tolerant on this score, but it just doesn't work for a single sailor to sit at the stern seat unless there is a whole lot of ballast up forward. And when tacking a canoe, it is common practice for the sailor to move forward, depressing the bow and changing the canoe's effective lines. (That same move also includes leaning to leeward to make the hull heel and the bow 'carve' to windward, but that is another story.)

    It can be difficult to place our crew for best weight balance because mast, rigging, and leeboard thwarts can get in the way.

    Enough for tonight. The wind is blowing at about 28 and my beached canoe just flipped on its side. There is some sort of lesson there!

    Bob

    P.S.: Longtime sailors may recognize the old British Seagull 40+ on the back of my little aluminum skiff in a couple of the pictures.
    Last edited by Bob Cavenagh; 24th-March-2017 at 01:20 AM.

  28. #28
    Join Date
    Jun 2016
    Location
    Eagles Nest Lakes, Ely, Northeastern Minnesota, USA
    Posts
    94

    Default

    Thank you for showing the different sail positions and for you detailed explanations. Much for the newbie like me to consider.
    SB

  29. #29
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Hull Balance and seating

    I make something of a point about hull balance because I have seen a number of canoes that have crew badly placed. In addition to my comments in the last segment, having the greatest weights (crew, primarily) near the middle of the hull leaves ends lighter and better able to rise to waves and chop. I recall one canoe in particular in which the sailor sat on the rear seat. The bow was out of the water and steering was downright squirrely.

    Crew are not only the heaviest objects in most sailing canoes, they are also usually the largest. Mast and leeboard thwarts can make seating awkward. Several options have been developed over the years to help make everything fit.

    As we look at seating, we are nosing into my point #5 (previous post) about comfort and convenience.

    In traditional sailing canoes, the sailor sat on the bottom, perhaps on a cushion. Here is a classic (and rather elegant) ACA style setup. Steering is by means of a paddle, not visible. The far (and leeward) leeboard is down and the bow is slightly high:



    Sitting on the bottom offers a number of advantages. The sail can be fairly low, the low crew weight gives stability, the sailor's legs can slip under the leeboard thwart when needed, and no extra seat is necessary. I suspect this sailor is sitting on a pad and leaning against a thwart that is not visible in the picture. He can move fore and aft and side to side as needed. The center of effort of the sail is approximately over the leeboard, and forward of midships.

    (If you want to duplicate this setup, ACA plans will show you how. Go to http://canusail.org/building/aca_rig.pdf)

    In a big and beamy canoe like this 19 footer, there can be quite a bit of room for the sailor to move around. The linked photo shows Ida Little, a noted canoe and small boat cruiser. She and her husband Michael Walsh have had many adventures in Florida and the Carribean:




    Unfortunately, this sitting arrangement is not comfortable or convenient for everyone. Some of us---moi, for one--- can't sit for long in this position. It is also necessary to be somewhat athletic to move to hike out to windward from such seating. In consequence, other seating styles have developed. They can shape other factors, like mast and leeboard placement.

    Much noted canoe designer and sailor Hugh Horton uses a very complex seat in his much praised Bufflehead canoe:



    This seat can be adjusted in multiple ways. It sits on the bottom of the Bufflehead and can be moved to adjust weight balance. While it is still a low form of seating, the backrest and other adjustments do much to increase comfort.

    Here is an expedient commercial alternative:



    Commonly called a sand or beach chair, it is lightweight. It lacks the adjustability of Horton's seat and concentrates its weight on the front and rear corners. The canoe bottom can be protected by adding a pair of longitudinal runners near the corners to better distribute that weight.



    A lot of sand blew into my canoe last night. The green carpet is a leftover from a previous owner, padding for their small children and canoeists' knees. Someday I will remove it and all the messy glue residue. The leeboard thwart (right front) comes very close to my knees.

    Another off-the-shelf alternative available from several vendors:



    This Old Town version is 10" from front to back, typical of commercial canoe seats. It is a bit higher than previous options. It is somewhat flexible and tends to pull the sides of the canoe inward. Resting it on a couple of cushions on the bottom can help limit that, and placing cushion(s) on top can rise the sailor's position usefully.



    Other canoes (especially some in the OCSG) have evolved seating further, with higher seats and side decks for hiking/sitting out. This rather nice video by Keith Morris of OCSG shows such an arrangement.



    The next bit of evolution actually seems like a regression: a return to decked canoes. Horton's Bufflehead and some newer designs by Solway Dory are good examples. But these canoes have little in common with 19th century predecessors. They are essentially our light open canoes but with decks. The decks offer some advantages: better ability to shed water, options for dry storage compartments/flotation, and a very significant increase in stiffness. Our open canoes use cross thwarts to hold leeboards and these can be an obstacle. Strong side decks allow dispensing with the thwart and mounting a leeboard directly to the hull, and they also open up new possibilities for seating and weight distribution. It is quite possible to deck an existing canoe.

    This picture of a Shearwater from Solway Dory's site reveals a long open area for seating, strong side decks suitable for sitting, and a side mounted leeboard without cross thwart. Just visible beneath the sailor's legs is a bench seat





    I think this is a very sufficient intro to the notions of hull balance and seating. Inventive sailors will find their own solutions, but here are the takeaways:
    -Concentrate weight somewhat aft of amidships. In general this means seating a solo sailor at that location.
    -Arrange for seating that is both comfortable and functional for the particular sailor (we come in many shapes, sizes, and abilities.)
    -Use this as a starting point for arranging sails and leeboards and rudders.

    Next time: Sails and Leeboards
    Last edited by Bob Cavenagh; 26th-March-2017 at 03:26 PM.

  30. #30
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Sails and Leeboards, with a peek at steering: Sail Types

    (This segment, like several others, is intended for novices. I have assembled lots of web links--no point in reinventing the wheel.)


    Once an initial approximation of hull balance has been worked out it is time to turn to sails. One must choose a sail type and then a size (of course, if you already have a suitable sail, then you can just skip ahead). Different types have different characteristics

    Contemporary canoe sails tend to fall into just a few pigeon holes. Perhaps the most traditional canoe sail is the lateen. My own Grumman lateen of 45 square feet has been illustrated in previous segments. The drawing below, by Chris Wentz, shows a typical setup. For more detail and a caution on lateen use in canoes, go to the site: http://duckworksmagazine.com/05/vintage/sbj/4/



    Lateens are still common in North America but apparently less so in Europe. They can be weatherly and work well across and downwind, but they are very difficult to reef effectively and when dropped to the deck, their spars are rather long and inconvenient. It isn't obvious in the drawing above but with that particular rigging, one of the two 'parrels' must be released before the sail can be lowered. There ARE other methods to resolve that. A number of US vendors can provide these ready made, but many are rather primitive nylon constructions. When you set sail with a lateen, you will have to deal with its fixed sail area no matter the wind strength. On a positive note, the center of effort of these sails is relatively low, reducing heeling effects. Over the years, sails of this type have ranged from 40 sq feet up to a whopping 75, with 45 being a common size.

    The long boom means that the mast must be stepped toward the bow of the boat.

    Traditional, but not my first choice for a canoe, but if you have one, use it.


    The balanced lug sail (my Optimist conversion above, for example) has picked up quite a number of canoe sailing adherents since WWII. I posted a different image far above, so here is a new diagram:




    The equally traditional balanced (or balance) lug can be relatively effective on all points of sailing and lends itself to easy reefing. Its center of effort (CE) is relatively low, though perhaps a bit higher than a lateen of similar size. The spars are relatively short, so it is usually easy to stow a rig on a canoe. Modern practice calls for a very powerful downhaul. This tightens the luff to improve windward performance.

    Australian sailor and designer Michael Storer is a strong proponent of these sails and he has published plans for a canoe that uses two:

    http://www.storerboatplans.com/Beth/beth.html

    He also offers a plan for a much smaller (21 sq feet) "drop in rig": http://www.duckworksbbs.com/sails/st...p-in/index.htm

    Boat designer Jim Michalak publishes a new design or explanation every two weeks; this one shows a method for reefing a lug sail: http://www.jimsboats.com/15sep11.htm

    I have also linked a page from Australian designer/builder Ross Lillistone, who touts the lug but also describes some other types http://www.duckworksmagazine.com/13/.../#.WNvzBjvyuCg

    Typical canoe sails have been in the 25-50 sq st range. These sails are 'balanced' because some portion of their area is on either side of the mast. There's some variation in how much of the sail protrudes, so mast position can be an interesting question for these sails.

    These sails are 'balanced' because some portion of their area is on either side of the mast.


    The Bermudan (or Bermudian) sail has gotten a lot of attention recently, in no small part because of the efforts of canoe sailing experts Solway Dory in the UK (and often active on this forum). Here is an image of one of their sails:



    They use a simple and effective reefing system in which the sail is rolled around the mast. (See their website for sizes and reefing instructions). Over the years, that company has tried and sold a number of sail types, including the current Bermudans and one lug sail. They have now dropped their previous 35 sq foot lug as their sense of possibilities evolves.

    Sails like these are not currently available in North America unless you have a sailmaker whip up a custom version. There ARE, however, lots of other Bermudan sails available, made for small dinghies. I have one from an 'Eli Dink' that is just fine, but it has battens that prevent it from reefing around the mast; a Bermudan sail can be jiffy or slab reefed just like the lug. Here is a more detailed ink on reefing. Intended for bigger boats, it can still work on a canoe:

    https://www.thoughtco.com/reef-the-mainsail-2915473

    There are other sail types as well. My Balogh sail (scroll WAAAY up) is fully battened and the battens force shape into what otherwise might be a rather flat piece of cloth. Much used on kayaks, the larger sails are also suited to canoes. They have a high Center of Effort which can make them heel more quickly than lugs or lateens, but they are also efficient to windward. This brand uses zippers to reef sail panels. I find reefing a bit fussy, but quite effective. Here is another:



    A number of folks have used similar looking windsurfer sails on canoes. In small sizes they can be ok but often have too much camber and are designed for a different tye of operation than is convenient on canoes.


    Choosing your sail type and size can seem a puzzle. Sails with long leading edges (lateen, bermudan, Balogh style) often have really good windward performance while lugs may give up a little efficiency upwind, but come into their own across and downwind. Newer high peaked lug designs and rigging have certainly improved their overall performance and they are generally rather handy sails for pottering about. Cost is often a factor; my own experiments (going rather well, thank you) with a modified Optimist sail point to an economical option.

    While sail sizes can prompt lots of discussion, here is a quick and very superficial guide: sails under 35 sq feet are generally easy to manage and can give adequate performance but may not be great windward performers.. From 35-45, performance increases and so does a need to manage the sail in high wind. Much above 45 is for the racer or determined athletic person. Of course canoe size enters into the mix, as larger canoes need a it more power

    Next I will take on the relationship between sails, mast placement, and leeboards.

    Bob
    Last edited by Bob Cavenagh; 29th-March-2017 at 07:22 PM.

  31. #31
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default An inspace--Opti update--and a question

    On the road, again. Our Florida rental ended today and we are headed north: 1050 miles in 3 days at 350 miles per day. We had some screaming winds before leaving, and just a few moderate days.

    On one of those days I took the Opti rig for a final trial spin. Quite successful. I had made some modifications to the yard and its adjustments. I found I could tack through about 100 degrees or better and the sail was docile in 7-9 mph. In short: this conversion of a $100 sail seems to have been a worthwhile effort. I expect to make a few gradual improvements, add some reef points.







    Do I recommend this as a project for someone looking for an inexpensive canoe lug? You bet. And 35 sq ft seems adequate for many situations.




    Now a question: I have been rabbiting on about setting up canoe rigs, not getting too much feedback. Is this little exercise worth continuing? I am really just organizing common knowledge, but some of the info is hard to track down. I am happy to continue but I'd also sooner stop than just fill up forum space uselessly.

    And the answer????

    My thanks,

    Bob
    Last edited by Bob Cavenagh; 2nd-April-2017 at 02:55 AM.

  32. #32
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default An inspace--Opti update--and a question

    Accidental repost while editing, please ignore.
    Last edited by Bob Cavenagh; 2nd-April-2017 at 03:41 AM.

  33. #33
    Join Date
    Nov 2007
    Location
    very soon to be norfolk
    Posts
    1,608

    Default

    Very interesting and hopefully useful. Please keep going.Sam

  34. #34
    Join Date
    Aug 2009
    Location
    Eastern England
    Posts
    1,186

    Default

    Please keep going. :-)

    I have one question to ask, which is the following: as you say SD over here are proponents of reefing by rolling the sail around the mast, but put up with a taller mast and greater CoE/heeling moment. Is there a reason why rolling the sail around the boom (which could be done with a standing lug) is more of a faff/less effective than rolling around the mast? I presume the answer is likely to be to do with the downhaul and/or the sheet--though presumably the former gets in the way of roller reefing around the mast too.

    Interesting to hear that the Balogh zip reefing is also 'a bit fussy'. I have wondered whether that might have been a simple method of reefing.

    Thanks.
    Ian

  35. #35
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Ian, a quick reply before we hit the road:

    The method SD uses is very simple. With a sleeved sail and no halyard, the only strings to pull are the sheet and vang and, while reefing, the boom outhaul. In the current setup the vang must be disconnected to reef (some tricky engineering could even eliminate that). (Even trickier engineering would let the sailor reef without moving from a seated position.)

    Reefing to or around the boom requires that the sail have a halyard and lines to pull the sail down and secure it, a manageable but somewhat more complex task. As you note, reefing around the boom often requires a change to sheeting.

    The SD sail rolled around the mast is probably flattened a bit and the rolled sail is a bit bulky up high, but those seem minor. The sail reefed to the boom retains more of its designed shape as it comes down.

    Both methods work, both have tradeoffs. The SD system is probably quicker.

    The Balogh issue is that the fittings around the mast are snug and the sail needs to be pulled down from near the mast. Good sail, but perhaps not surprising that many are fitted to canoes/kayaks with outriggers which give a bit of stability during that process.

    Bob




    Quote Originally Posted by idc View Post
    Please keep going. :-)

    I have one question to ask, which is the following: as you say SD over here are proponents of reefing by rolling the sail around the mast, but put up with a taller mast and greater CoE/heeling moment. Is there a reason why rolling the sail around the boom (which could be done with a standing lug) is more of a faff/less effective than rolling around the mast? I presume the answer is likely to be to do with the downhaul and/or the sheet--though presumably the former gets in the way of roller reefing around the mast too.

    Interesting to hear that the Balogh zip reefing is also 'a bit fussy'. I have wondered whether that might have been a simple method of reefing.

    Thanks.
    Ian

  36. #36
    Join Date
    Jun 2016
    Location
    Eagles Nest Lakes, Ely, Northeastern Minnesota, USA
    Posts
    94

    Default

    Do continue, please. I've been following this closely. Thank you for this thread.
    SB

  37. #37
    Join Date
    Nov 2010
    Location
    grange over sands, cumbria
    Posts
    931

    Default

    At SD we made a few standing lugsails that reefed by rolling the sail around the boom, but you lost the ability to control the sail shape because the adjustable outhaul disappeared under the sail cloth. Also we used a vang to control sail twist, and again this would get lost in the rolled up sail. I got around this by putting the vang/kicker onto the clew (outer end) of the boom hanging from a swivel, but again it didn't work well enough. The roll around the mast is definitely the quickest and easiest for reeling. Also you retain all of the sail shape control ability. Even when it is reefed you can add lots of shape by easing the outhaul, if you need it. The sail cloth wrapped around the mast doesn't appear to spoil the drive from the rig as much as you would expect, but that's probably because the diameter increase from a few wraps of sail is marginal.
    Do keep up with your writing Bob. I read everything you write,as I am sure lots of people do. You talk a lot of sense and it is good to get a perspective of what is happening across the other side of the pond

  38. #38
    Join Date
    Aug 2016
    Location
    Near Heusden (NL)
    Posts
    24

    Default

    Please continue, I find the various design considerations very interesting, indeed..

  39. #39
    Join Date
    Jan 2013
    Location
    Ft. Worth, Tx
    Posts
    168

    Default

    I hope this is not a repeat, but Todd Bradshaw's book may be of interest to you .
    There may well be several additional options.
    https://www.amazon.com/Canoe-Rig-Ess.../dp/0937822574

    I have a copy and I find it fascinating.

  40. #40
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Bradshaw's book

    There have been a number of books on sail rigs for canoes, some of which are quite good. Bradshaw's is NOT good. It's GREAT. I have two copies, against a rainy day, and recommend it to any who like to read in depth.

    That said, his primary focus is on antique and traditional canoes, so some more modern trends are not covered in much depth. Bradshaw is often active--very active--on the Wooden Boat Forum and others and dispenses great advice on sails and rigs.

    Bob


    Quote Originally Posted by MarcUp View Post
    I hope this is not a repeat, but Todd Bradshaw's book may be of interest to you .
    There may well be several additional options.
    https://www.amazon.com/Canoe-Rig-Ess.../dp/0937822574

    I have a copy and I find it fascinating.

  41. #41
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Center of Effort and Sail Placement, 1

    I've been a bit slow in resuming this thread. Mea culpa. After returning from Florida I discovered that my 'to do' list had grown notably. Hopefully that will ease off a bit.

    An aside: On the way back we stopped in Roanoke, Virginia where we found an excellent restaurant and I made a second pilgrimage to Black Dog Salvage. There isn't too much nautical about that place--mostly architectural and interior salvage--but it is a great delight for folks who enjoy old and quirky and sometimes old and quirky and spectacular. And sometimes new things made of old stuff....if any of this sounds interesting, stop in if you are passing Roanoke :http://www.blackdogsalvage.com/

    Last time around I was bloviating about different sail types, and there is much more that can be said about choosing one or another. But lets imagine you have picked out a sail--perhaps a lug--of size X. You have already worked out weight placement and hull balance for your canoe. Where do you place the thing? Where does the mast go (and with it a mast thwart and step). Where do you park the leeboard(s)?

    I have been mentioning something called Center of Effort. The phrase SOUNDS as if that is the point at which the sail concentrates its efforts. Right??? Not quite.

    I'm reposting an image I grabbed off the web (if any of this stuff seems important, better download it when you can--the web is fickle).



    The 'center of effort' is plainly marked in the middle of the sail. The phrase is a bit misleading, as that point is really just the geometric center of the sail's area. The actual points (or more typically lines) at which the sail's thrust is concentrated can be in different places at different times. Several noted nautical authorities (Howard Chapelle and John Gardner, for two) have described this 'CE' and a matching measurement of a hull's center of lateral resistance (CLR) as convenient fictions that can provide starting points for the placement of sails and centerboards/leeboards, keels, etc.

    If you scour textbooks and the web you will find all sorts of descriptions of CE and CLR. Many are confusing and a few are just wrong. Fortunately, as canoe sailors we can often ignore a lot of that and proceed by rather simple trial and error. But, to keep ourselves from blundering way out of the margins, we really can use knowledge of that hypothetical CE and where it occurs on our chosen sail.

    Forgive me if I channel Monty Python and the Undertaker sketch http://www.montypython.net/scripts/undertaker.php

    We could measure the CE, or we could calculate it, or...we could eyeball it. (I AM feeling a bit hasty).

    Two thirds of a lifetime ago, a Field Artillery instructor burned this lesson into my brain: "learn to trust your eyes."


    Because our canoes are (mostly) symmetrical) and because we have worked on balancing the hull weights and crew placement, we can guess very approximately where the sail needs to be. Set the sail up temporarily using a mast on another hull, or a flagpole, or a big stick supported by cement blocks. Standing as nearly perpendicular to the middle of the sail as possible, take a snapshot of it, download it to a computer or tablet, and study the sail. I did that with my little Opti sail:



    Then make a really good guess as to the location of that elusive 'CE.' Here I have marked it and dropped a straight line down to the hull.:



    Here are some things to observe: The nominal 'ce' is about 16" forward of the center thwart that denotes the center of the hull. At this point, the mast is parked in an existing mast thwart and step that are rather too close to the vertical ce line. My nominal seating position will be roughly between the center thwart and the rear thwart in a very cramped location, and if I make no changes, my legs would have to be under the center thwart to achieve hull balance. Finally, I will need to park the leeboard and its thwart somewhere in this mix. All in all, this would be rather uncomfortable. On a positive note, the CE isn't too far forward from the middle of the hull, a good thing.

    In this example, I will want to rotate the boom aft, splitting the distance between the mast and the tack of the sail. This will reduce the area in front of the mast and will also raise the rear of the boom. And the nominal 'ce' will also move a bit to the rear.

    A few segments ago, I said that the ideal thing is to have the leeboard position, the nominal ce, and the hull weight balance all pretty close to centered fore and aft. The problem with doing this in a canoe is that things can't all fit in the same space, especially large sailors. Some compromises will be necessary, and that is ok.

    For this project I will move the mast position forward about 8-10 inches. That will entail a new mast thwart and an new mast step. With the boom rotated aft, the 'ce' will still be near its current location. And then I will install the leeboard thwart experimentally (a beauty of using a leeboard on a canoe is that both the thwart location and the board angle can be adjusted to suit our needs. I will place it nearly up to the old mast thwart location and then go sailing in modest wind.

    Like a new marriage, a leeboard location needs to go through a 'period of adjustment.' The goal is to position the board so that the hull tries to turn up into the wind. My suggested position did that, and then I gradually moved the thwart to the rear until this windward tendency ("weather helm") was rather moderate.

    Over at the ACA, Marilyn Vogel gives a quick but useful overview:

    http://freepages.genealogy.rootsweb....r/aca_rig.html


    This process requires a bit of pondering but is easy enough in practice. I will stop for now, but here is a one 'cute' but useful little addition on balancing canoe hulls, mostly for paddling:

    https://paddling.com/learn/the-curio...nd-mr-pink-or/


    Bob
    Last edited by Bob Cavenagh; 11th-April-2017 at 02:21 AM.

  42. #42
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default That pernicious leeboard thwart

    (These posts are for the benefit of novices. I am always glad to receive comments and questions...)

    In the last segment I mentioned that, once hull balance and mast position are determined, the exact position of the leeboard(s) and thwart are worked out somewhat experimentally. That is all pretty straightforward, but the leeboard THWARTS can be a nuisance. One of the reasons we often put the mast a bit further forward than we might prefer is that the leeboard thwart can get in the way of the sailor. By moving both forward we create a little additional knee room, and that can make the whole enterprise more comfortable.

    This very nice Old Town confines the sailor to the space between the leeboard thwart and a cross thwart, so he/she will mostly sit on the bottom.



    There ARE other options. A few segments ago I linked an image of a Solway Dory decked Shearwater:



    This combination of sturdy decks and internal supports creates a cockpit with lots of open crew room. It also provides strong support for a side mounted leeboard without a cross thwart. That is a fine combo, and one with lots of history.

    This little image of Bufflehead shows a different and very creative mounting system and reveals the openness of the cockpit and the adjustable, reclining, and movable seat:



    One limitation of these two side mounted leeboards: the position is locked in at the time of construction, so the designer and builder need to get the mast and leeboard positions 'just so' before finalizing the design. I did once see a sliding side mount, but it was a bit of a contraption.

    Note that this hull uses two push-pull tiller extensions, for use with either hand. Bufflehead plans are available, but it is not a design for a novice boatbuilder.




    'Pretty Jane' (above) revisits the style of 19th century canoes. I think I recall that there is a folding centerboard under the raised forward portion of deck, but this structure could also easily support a side mounted leeboard. The use of two sails opens up the middle of the hull rather dramatically. In the 19th c., what we now call a 'cockpit' was commonly called 'the well.' This design allows the sailor to sleep aboard.

    I have been experimenting with 'bridge thwarts for leeboards. The only picture I have handy is from my first attempt, and the setup is rather congested with two leeboards in temporary locations.



    The lower, aluminum thwart is for one type of Grumman factory board while the wooden structure shows why I call it a bridge. It provides about 5 inches of additional clearance for feet, knees, etc. Those few inches make a really significant difference in choice of seating positions and can increase crew comfort a lot. I have made others since that are a bit more refined. The additional height allows me to sit higher for comfort and convenience in hiking (sitting out). I have combined a similar wood structure with strong aluminum angles that let me place the leeboard pivots lower than the gunwale. As long as the structure can take the strains, mounting the leeboard low puts more board in the water and less high up where it can snag lines, etc.

    One of the niceties about using a leeboard is that we can vary its angle to help balance the rig in different wind strengths. But (one might ask) WHAT IS THE OPTIMAL ANGLE FOR A LEEBOARD?

    More on that next time.

    Bob
    Last edited by Bob Cavenagh; 16th-April-2017 at 08:23 PM.

  43. #43
    Join Date
    Jul 2008
    Location
    Southport, really in Lancashire, UK
    Posts
    2,042

    Default

    Worth a good read, I will be back.

    Some photos still missing e.g. no 41 image after 'I did that with my little Opti sail:"

    Doug
    When there's trouble on shore, there's peace on the wave,
    Afloat in the White Canoe.
    Alan Sullivan


  44. #44
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Hello Doug,

    Thanks.

    I get frustrated with posting Google Photos images. They have huge identifiers and seem to exist in different versions. Tell me which you can see:

    1.

    or 2.


    I have had trouble with sharing settings, but these both seem free of all that. I see them both, but my phone, tablet and computer are all dialed into Google Drive and Photos, so permissions can get lost in the mix.

    My thanks,

    Bob

    Quote Originally Posted by dougoutcanoe View Post
    Worth a good read, I will be back.

    Some photos still missing e.g. no 41 image after 'I did that with my little Opti sail:"

    Doug

  45. #45
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Some nautical porn while I fuss with images

    I am digging into image issues. Not so much fun. But these ARE. Every October I go to the Mid-Atlantic Small Craft Festival in St. Michaels Maryland, USA. If you are ever on the US east coast at that time, try to attend.

    It is not all canoes, but there ARE canoes if you look, and some beauties. Even a fiberglass Old Town Wahoo for contrast. If you like small boat sailing and good craftsmanship, this is a great place.

    http://forum.woodenboat.com/showthre...3-Photo-Thread

    http://forum.woodenboat.com/showthre...4-Photo-Thread

    Enjoy,

    Bob

  46. #46
    Join Date
    Jan 2011
    Location
    Washington State, USA, shores of Puget Sound
    Posts
    503

    Default

    "This is really a tough, unpleasant working environment"

    Sheeeesh......

  47. #47
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    How about the links in #45????

  48. #48
    Join Date
    Jan 2011
    Location
    Washington State, USA, shores of Puget Sound
    Posts
    503

    Default

    The links are good here, Bob. Keep writing.

  49. #49
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Leeboard angles and other ephemera

    A nicety of a leeboard is that it can move through a range of angles to change the lateral resistance of the canoe and thus help manage weather and lee helm. Within some limits that is a good thing--but just what ARE those limits? Let's take a look. (I am hopeful that my images issues are resolved...)



    In theory, the ideal position for a leeboard is VERTICAL. This insures that the maximum amount of board is in play. The dark dot on the leeboard approximates the center of area for the immersed portion. The board in the sketch is a bit over 4 feet long with roughly 3 feet immersed. This would be typical for many canoes using only a single leeboard (a canoe that alternates 2 leeboards would have shorter ones).

    Leeboard SIZE is related to sail area. Different numbers have been put forward, but an immersed portion that is something around 4% of sail area is in the ballpark. Length vs. width are a whole additional discussion, but a modern trend is to longer and narrower boards.

    As the canoe sails along, friction with the water ('drag') tries to push the board to the rear, so the leeboard thwart or other mount must resist this. Another and frequently much greater force arises as the board develops LIFT and makes the canoe heel. When the board is on the lee side (ie: downwind), this force tries to push the board toward the middle of the canoe and places a downward force on the thwart or mount. This downward push on the gunwale of the canoe is typically easily resisted by the gunwale. But, if a single board is carried on the WINDWARD side of the hull, that same force tries to LIFT the gunwale, so the thwart needs to be well secured; gunwales are not always as strong when lifted as when pushed down so what ever clamping is used needs to take this into consideration.

    A quirk of the vertical position: sometimes, depending on the profile of the board, water may climb upward and even splash into the hull. To combat this tendency, and to adjust helm pressures, many boards are raked just a bit aft:




    Note that the effective area of the board is reduced just a bit, and the effective center has moved aft. If the rig balanced well with the board vertical but splashing occurred, this is a good solution--but the pivot of the board can be moved forward so balance doesn't change. The various forces are pretty similar to the case with the vertical board.




    This image shows a much more radical change--note how far the center spot has moved aft and that considerably less board is immersed and functioning. A board in this position imposes some twisting forces on the thwart or mount. It is generally a rather extreme position for a leeboard, with much efficiency lost, but it may be useful at times. Some designers have made use of this kind of rake to simplify leeboard installation. Micheal Storer created what he calls a 'drop in canoe rig':



    He couples a small sail and a long leeboard and integrates the mast and leeboard thwarts. As sail size increases, this becomes less feasible. Balogh Sail Design does something similar, but they still recommend a more conventional thwart be used when their sails are rigged on canoes rather than kayaks:




    The Balogh sails are tall but narrow, which helps this application to work.




    When sailing downwind, leeboards are often lifted clear of the water but sometimes it is helpful to trail just a bit of board to improve tracking. Note how much of the board is out of the water and not functional.

    There is one other position (actually, a range of positions) that are generally to be avoided.




    If a leeboard is raked FORWARD and it encounters a rock or hard bottom, the resulting collision can damage the board and hull, slew the canoe around, and even cause it to capsize. Water also tends to climb a board that is raked forward.

    This is just a quick overview, showing general principles.

    Bob

  50. #50
    Join Date
    Apr 2009
    Location
    West Yorkshire
    Posts
    3,656

    Default

    Quote Originally Posted by Bob Cavenagh View Post
    Another and frequently much greater force arises as the board develops LIFT and makes the canoe heel
    Those who paddle more than they sail will recognise the parallels with a static-draw: a blade held at a slight angle to the direction of travel of the canoe.

    When paddling on a calm day, the canoe may be moving straight forward... so a blade placed exactly parallel to the keel-line does nothing: it's a neutral slice. In a strong cross-wind, whilst paddling forwards, the canoe is also getting blown sideways... so the blade which is parallel to the keel line is aligned with the direction of travel.

    Ideally, that blade would be a "foil" (like an aircraft wing) to generate lift... but for other paddling purposes that would not be ideal... so we manage with a conventional blade shape... but we still aim at smooth flow on both sides of the blade, with the flow on the one side being fast, generating lift.

    Ps. One interesting aspect - as the canoe heels the gap between the centre of effort of the sail and the centre of effort of the leeboard can grow or shrink depending on whether the leeboard is on the upwind gunwale or the downwind gunwale. This can warrant a different fore-aft position on each tack.

  51. #51
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Nice observations, didn't think to mention the difference between tacks with a single board. Thanks!

    Bob

  52. #52
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default A bit more on leeboards

    A lot of ink (or electrons) has/have been engaged in discussions of leeboards, especially the size and shape of boards.

    Leeboards are the most common means of preventing leeway for sailing canoes. Sitting outside the hull, they don't take up scarce space. Most are designed to pivot so they can be adjusted, and can kick up in a grounding. Commonly made of wood, they are usually held down by friction or by a combination of friction and some weights--probably lead--carried low down.

    These boards can develop a good bit of sideways force, which promotes heeling. To counteract this force, one typically moves to the opposite side of the hull, perhaps even hiking out (sitting out) over the rail. This means that the thwart or other structure that supports the board must be strong enough to resist that force. There are lots of strategies for that, using wood, metal castings, aluminum allow angle, or the deck mounts I mentioned previously.

    The boards must be strong enough to resist bending and breaking. For this reason, solid wood is generally considered a much better option than plywood; the x-y axes of plywood aren't so good at resisting these forces (there IS a way to increase the strength of plywood, by laminating 5 or more layers with the grain running up-down/side to side on three, and at 45 degree angles on two. I can sketch that if this is confusing...)

    Leeboards have two shortcomings compared to centerboards, daggerboards, and keels: they are more likely to pick up floating debris which is often pushed aside by, say, a centerboard.
    They also lack the 'endplate' effect created when a centerboard enters the hull, diverting and shedding vortexes. We seldom observe this effect but may see circular swirls around the board in moderate wind. There is little we can do about either of these, and no need to avoid leeboards, but they are interesting little tidbits.

    Leeboards need some shape: a rounded and moderately tapered leading edge and a thin trailing edge. Fanatical sailors turn to something like 'NACA foils' for shape guidelines, and often to an 0012 foil (search the web for details on these):



    For more casual sailing it isn't necessary to duplicate this exactly, but the rounded and tapered leading edge and the strongly tapered trailing edge ARE useful. The trailing edge shouldn't be as extreme as in the drawing as a sharp edge is weak and may break down in use. A squared off edge of perhaps 1/4" width is usually fine.

    The leading edge of a leeboard is subject to abuse from rocks, dirt, etc, so it is wise to reinforce at least the board's edge with something like epoxy/fiberglass. An entire board can also be 'glassed.

    A well-shaped leeboard and rudder can enhance windward performance, but differences from a lesser foil can be hard to detect.

    A flat metal plate can also be used as a leeboard, though this has never been common on canoes. It would be functional but not optimal. Again, if you are curious I can explain.

    Leeboards and masts/sails work in tandem to create heeling forces. Heeling is a useful safety valve--when a hull heels, some wind is spilled from the sail and the sail also presents less area to the wind. Hiking out opposes those forces and puts more pressure on both leeboard and sails. The use of outriggers, either the modest gull wing safety outriggers that are now popular, or full sized, constantly immersed versions, can significantly increase the side pressures encountered by leeboards, mounts, and masts. If you use these outriggers, do give special attention to building in adequate strength.

    Next steps: masts and their gear.

    Bob
    Last edited by Bob Cavenagh; 24th-April-2017 at 12:57 AM.

  53. #53
    Join Date
    Jan 2011
    Location
    Washington State, USA, shores of Puget Sound
    Posts
    503

    Default

    A good explanation on leeboards. The section view is critical with regards to avoiding having water climbing the FWD edge at higher speeds. With my setup, having the leeb'd thwart inverted with the "ears" pointing down, along side the hull, this is very important, and I faired my Grumman 'scaffold planks' down to resemble a trout when viewed from above. Just like the drawing you show. Properly shaped, leeboards can be run angled forward to gain bite while tacking and still not dump water into the boat.

    Also, the departing edge treatment is important, and you mentioned that as well. If the edge is too fine it will not only be fragile, but it can create turbulence as the two sides spill off the foil and converge . A flat edge of about 3-5 mm leaves a small eddy just aft and lets the water flow back together smoother. Leeboards like this are not only more effective, but run quieter as well.

  54. #54
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default Masts, halyards, vaangs, downhauls.

    Every type of sail needs a suitable mast. I want to look at just a few common types and describe some characteristics.

    Lets start with triangular sails that attach to masts. Here is a Solway Dory link I used before, with a Bermudan sail:



    The sail is sleeved to the mast. The mast itself is both tall and fairly thin. (I believe it is two aluminum tubes, the upper being smaller than the lower.) The mast passes through a hole in a thwart and there is no doubt some sort of mast foot on the bottom of the canoe. A small and hard to see line pulls the foot of the sail downward and thus tightens the luff. It is a very modest 'downhaul.'

    There is a vang or kicking strap (the diagonal line) that is pulling the boom downward and forcing a bit of curvature into the mast. This helps shape the sail, and limits how much 'twist' the upper part of the sail can develop. It is attached to the mast. There is an 'outhaul' to pull the sail rearward for flatness, or eased, to create draft and power in the lower part of the sail.

    There is no halyard. The sail can be reefed or furled around the mast.

    The force developed by the sail is delivered to the mast and to the sheet that controls it. Because this force is spread over the entire length of the mast, no one point on it has to resist much of that force and a light mast works well.

    The amount of 'pull' experienced on the sheet is determined by wind strength and vang setting. This type of sail really profits from a vang--they were not so common before WWII.

    The only connections from rig to hulls are the mast and the sheet. In an emergency the entire rig can be lifted out and tossed over the side where it will serve as a sea anchor, retained by the sheet. About the only big downward forces on this mast are the weight of sail, mast, and boom. It sits rather lightly on its step.

    Here is another Bermudan sail, with some differences:



    (I couldn't spot an image of this rig variation on a canoe.) It is similar to the version above EXCEPT the sail isn't sleeved to the mast. In this particular version, a rope sewn to the luff of the sail is held in a groove in the mast. The sail is raised and lowered with a line to the masthead called a halyard, and that line is cleated to the right side of the mast. Its a little hard to see, but it is there. A sail could also just be laced to a mast.

    Same sort of vang, same sort of boom. This particular mast (a bit heavy for a canoe) is held upright by 'stays and shrouds'--guy wires to landlubbers. A canoe version could dispense with those.

    This sort of sail is reefed by lowering sections of it to the boom and fastening them in place with ties. It is also a valid rig, and very traditional. Since the halyard terminates on the mast, it too is rather light on its step.

    To compare the two Bermudans: since the first reefs around the mast, the sail can't be lowered, short of removing the whole thing. On this second version the sail can be removed into the cockpit, leaving the mast standing. The first lacks a halyard, the second uses one. Halyards will soon get more interesting, but we have a couple of others sails to consider first.

    The next sail LOOKS very similar but has important differences:



    It is another triangular sail, this one frequently called a 'leg of mutton', or a 'lego' to some wags. It can be laced or sleeved to a mast, or run up with a halyard.

    The boom has been replaced by an odd-looking stick called a 'sprit boom.' The rear of this boom is tied to the clew of the sail and its front is connected to the mast with a line called a 'snotter.' This boom combines the functions of the more normal boom AND the vang. As the snotter is tensioned, it flattens the sail and perhaps bends the mast to makes it even flatter. This can cover a wide range of sailing conditions; it has been classed as an 'automatic transmission.' But....

    I show this sail mostly for comparison. It has a couple of weaknesses for canoes: it is very hard to reef, and the sprit boom can be awkward aboard a canoe.

    For all three of these sails: tall mast, relatively high centers of effort, light rigs, good potential to windward.


    Next in line: our friend the lug sail.




    Meet DOT, a famous 19th century canoe with a balanced lug sail. This particular sail has two long battens, but they are not important to the discussion. The rig uses a yard to hold the head of the sail, and so a halyard is essential to raise that yard. It is small but one can just make out two lines leading from beneath the boom and back to the sailor's position. The upper one is the halyard, the lower is a downhaul that attaches to the boom. The little circles are schematic blocks (pulleys).

    The halyard runs up the mast, passes through a block that leads to near the middle of the yard. Another little block there leads the halyard back around the mast and it then is tied further forward on the yard. This little loop of line along the yard is a parrel and it holds the boom close to the mast. There is another parrel around the mast at the boom. (There are two more on the battens, but lets ignore the battens for now, and pretend they aren't there.)

    When halyards are used on canoes, it is generally desirable to lead them (and downhauls) back to the sailor's position. It can be awkward and even dangerous to have to move forward to strike a sail. The mast here is shorter than the Bermudans, and the center of effort is relatively low. With a lug, everything but the mast can be dropped and stowed. (There are some setup options that make it easier to drop a mast in a seaway without going forward.)

    Halyards, especially long halyards led to the cockpit, should be made of very low stretch line such as Spectra or Dyneema. That is also good for downhauls.


    The forces developed by the sail are transmitted much differently here. The yard, sail, and boom either press against the mast, or pull on their two parrels. Thus much of the sail's force is transmitted to just two points on the mast. The mast for a lug sail needs to be strong to handle those very concentrated forces. A little flex is ok to act as a spring in a strong gust, but we don't want the mast to bend much in normal sailing.

    Something else is happening here, too. The downhaul passes through a block on the deck. The force on this tackle (and it can be strong) is therefore pushing the mast downward into its step. On this canoe the halyard passes through a block on the mast, so it tends to pull the mast to the rear. That isn't always the case. Halyards often are pivoted to the mast thwart.

    I rigged an Old Town Chipewyan canoe with a lug sail and discovered that the forces of a halyard plus downhaul pivoted at the mast thwart were sufficient to distort the flat bottom of the canoe.

    There are a number of ways to set up halyards and downhauls:

    If they terminate on the mast, all forces are retained in the mast (but they can be hard to reach in a canoe).

    It they terminate at a thwart, strong downward forces can be set up.

    If they pass through turning blocks on the mast there is no added downward force, just rearward force on the mast.

    There are lots of possible variations, and in many cases extra downward forces are of no consequence. Most aluminum canoes, many fiberglass/composite canoes, many wooden ones, and SOME royalex/poly canoes are stiff enough. Some poly and royalex canoes deflect easily, especially those with unreinforced flat bottoms. In planning a mast installation, one needs to investigate hull stiffness.

    If you have a canoe with a rather flexible bottom, there are a number of ways to eliminate the impact of halyards or powerful downhauls. One option is a mast tube that is bonded to both step and thwart.

    Our first two Bermudan rigs could be set up with pivoting masts. Our lug with its halyard and downhaul makes that more difficult. Pivoting masts are another interesting topic.


    Enough (or maybe too much) for now.

    Bob
    Last edited by Bob Cavenagh; 24th-April-2017 at 03:12 AM.

  55. #55
    Join Date
    Nov 2010
    Location
    grange over sands, cumbria
    Posts
    931

    Default

    The SD Bermudans are laced, rather than sleeved, to the mast. We found that the laced sails are much more controllable with the simple downhaul. The sleeves are very difficult to make with just the right amount of stretch on the luff, and sometimes multipart blocks are needed to pull any luff creases.

  56. #56
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Quote Originally Posted by DaveS View Post
    The SD Bermudans are laced, rather than sleeved, to the mast. We found that the laced sails are much more controllable with the simple downhaul. The sleeves are very difficult to make with just the right amount of stretch on the luff, and sometimes multipart blocks are needed to pull any luff creases.
    I could have sworn the red sail I grabbed as an example was sleeved. But I take your point. I am quite a fan of your rig!

  57. #57
    Join Date
    Nov 2010
    Location
    grange over sands, cumbria
    Posts
    931

    Default

    That picture does look sleeved, but perhaps it was a prototype.

  58. #58
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Gotcha!

  59. #59
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    283

    Default

    Just curious, Dave.

    Do you folks make all your own sails? That is a whole different skill set than boatbuilding.

    Bob

  60. #60
    Join Date
    Nov 2010
    Location
    grange over sands, cumbria
    Posts
    931

    Default

    Yes we make up the sails. (Or at least one of my partners does the sewing etc)

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •