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Thread: Slow progress

  1. #1
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    Default Slow progress

    My plan was to make a triangular support for the mast. I recovered some suitable wood from my neighbours door, which she had replaced.



    Here I've clamped the beam from a pallet onto the gunnels. The original base support for the windsurfer mast has been fixed to it.



    I need something between the posts to put the mast through. The large section from the middle of the door seems suitable:


    I need to draw a circle but I don't have a compass. Side project to make one so I can draw that circle...




    Countersunk a hole for the nut.


    Hammered it into the wood.


    Marked the length of 8mm threaded rod to length:


    And here we have the newly made compass:


    Thanks go to John Heisz for the idea.

    At this point I realise that I don't need that compass. Doh!

    I need a larger hole for the mast than I can drill out. Lathe time coming...

    Drill a hole for the screw chuck:


    Attach screw chuck:


    The screw chuck is now held in the four jaw chuck in the lathe:


    MIND YOUR FINGERS!!


    I cleaned up the surface and marked the circle size I need. Notice now why I don't need a compass to draw that circle?


    I turn a recess so I can reverse the block and mount it directly on the jaws of the lathe chuck:




    The reverse is cleaned up and marked out:


    Now I drill in with a parting tool, hoping to meet the hole on the other side. Reminds me of the Euro tunnel and how accurately they drilled from France and England to meet under the channel.


    Tada!


    Hole cleaned up and the surface as well:


    I cut slots for the posts to join the block. Here it is being tested for feasibility on the canoe:


    I marked where the block met the posts and then used my new compass to draw circles on the ends and round them off. I drilled 13mm holes for wooden pins after a lot of deliberation about whether to use a threaded rod or a wooden pin.


    These spindles that came from a chair I found in a skip will do nicely for the pins I need. (I'm a proper Womble!)




    A few minutes later:


    Yup, looks like that'll work nicely:


    Now looking at it on the canoe and thinking it's a lot bigger than I had in mind.


    But I realise that the supports are so long that the sail can't come down all the way now. Hmmm - more head scratching.


    Please excuse my neighhbour's wall, he had cavity insulation and the paint they used to cover the holes wasn't suitable. Now it's peeling off and looks terrible.

    So now I'm left wondering whether to shorten the posts so that the sail can come down further, or to trim the sail to shorten it. I'm also not sure about the size of the sail. I think it might be a bit too big. I'm open to suggestions and advice now.

  2. #2
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    Couple of things... I turned a mast foot by screwing a chunk of iroko ( chemistry lab bench top) to a faceplate, drilling a central hole with a forstner bit and attaching it to the bottom of the boat with Velcro. Mast goes through a hole in a teak ( recycled windowsill) thwart and sits in the foot. This eliminates the torque which will break your rig. Stays in the boat all the time and doesn't get in the way.
    Anyone can do that with two blades...

  3. #3
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    More sail is better, IMO.
    Since the boat will get knocked down with more sail or wind (or both), there is a limit to the benefit for longer "side stays".
    I suggest shorter supports.

    But what do I know. Just an opinion.

  4. #4
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    Quote Originally Posted by Nimbus View Post
    Couple of things... I turned a mast foot by screwing a chunk of iroko ( chemistry lab bench top) to a faceplate, drilling a central hole with a forstner bit and attaching it to the bottom of the boat with Velcro. Mast goes through a hole in a teak ( recycled windowsill) thwart and sits in the foot. This eliminates the torque which will break your rig. Stays in the boat all the time and doesn't get in the way.
    My rig's weakest point is the mast. That'll break before the structure holding it in place.

  5. #5
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    Quote Originally Posted by MarcUp View Post
    More sail is better, IMO.
    Since the boat will get knocked down with more sail or wind (or both), there is a limit to the benefit for longer "side stays".
    I suggest shorter supports.

    But what do I know. Just an opinion.
    Thanks MarcUp, I tend to agree. I think the two side stays should meet the mast at about 90 degrees. I'm not sure why I think this, but it "feels" like the optimal balance between support height and benefit from the tension and compression on them when force is applied by the wind.

    I tend to agree with the sail height and size. My plan is to be able to furl the sail on the mast so I can always just furl it in when the wind is howling.

    Thanks for your thoughts; it really helps to bounce ideas around with other people.

  6. #6
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    I know that "No Idea" has built a vertically mounted mast support, but this is a bit unusual and over the top. For most people, just mounting a mast foot to the bottom of the canoe and a mast thwart at gunwale level is all that is needed..http://www.solwaydory.co.uk/articles...xpedition-rig/
    If you find that the canoe flexes too much in strong winds, it is much neater and easier to brace the mast foot to the thwart http://www.solwaydory.co.uk/news/new-braced-mast-thwart

  7. #7
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    Quote Originally Posted by DaveS View Post
    I know that "No Idea" has built a vertically mounted mast support, but this is a bit unusual and over the top. For most people, just mounting a mast foot to the bottom of the canoe and a mast thwart at gunwale level is all that is needed..http://www.solwaydory.co.uk/articles...xpedition-rig/
    If you find that the canoe flexes too much in strong winds, it is much neater and easier to brace the mast foot to the thwart http://www.solwaydory.co.uk/news/new-braced-mast-thwart
    I do prefer the foot in the canoe, but I'm not keen on a permanent foot in there because I like the hull clean of gear when I'm canoeing. Hence me following Gary's design. I'm sure I can make a foot that's braced by the thwart on either side, and other braces fore and aft to keep it in place regardless of the direction of force.

    Again, thanks for the suggestions and feedback; it's all very much appreciated.

  8. #8
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    Not sure how big your sail is, but you will find that it reaches a size where you can't hold it up. I built a really big rig with a 22 foot tall mast and wondered why I was still unable to keep up with other canoes with smaller sails. I later discovered that they had beamier canoe hulls and could hold more sail up, whereas I had to reef down. I cured the problem by adding hiking out racks.

    As for your thwart design, it is interesting, though as you have discovered, your sail fouls on it. I have however spotted another potential problem. What is stopping the rig from falling forward or backwards? When you sail downwind the forces on the mast will try to push your mast forwards and from what I can see, there is no strength in those directions.

    As Dave has said above, mounting a mastfoot on the floor of your canoe solves all your problems.

    If you feel it is necessary, why not do both. Mastfoot on the floor and bracing above and below the thwart?

  9. #9
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    My mast foot is held down with velcro. All the forces on it are shear which is how Velcro works best. It's a rounded cone shape so it's not in the way usually. The forces on the gunnels are also in shear if you do it this way. Bolting the rig to the standard old town gunnels is asking for trouble.. (IMHO)
    Anyone can do that with two blades...

  10. #10
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    Please look again at the size and height of the sailing rig in the photos above. Then imagine the leverage forces that are likely to be transferred to the mast foot! They will be huge, far greater than velcro will cope with. In fact I wouldn't even risk gluing down a wooden mastfoot with g-flex (Probably the best glue available for plastic canoes) as you are in danger of this separating too!

    If a mastfoot gives way while in use, you can say goodbye to your mast thwart also!

    If you were using a small 10 to 20 sqr foot sail, I would say you could get away with things like velcro, but not rigs that size.

    Initially, I too was precious about drilling through the bottom of my canoe to secure my mast foot in place, but in the end, after watching my canoe twist under the forces being applied to it through the mast, it was only a question of when the mast foot comes unstuck, not if it would.

    If you want the power of a big sail, then you need to ensure the attachment points can handle these forces. Anything less will end in tears.

    A sped up video below of my big rig in action. Note how beefed up my mast thwart is, plus the belt and braces of my outrigger beam, which the mast passes through. I have also added another 50 rivets to my gunwales to stop them popping off under the extra force. Plastic canoes typically have gunwale rivets at 1 or 2-foot spacing, which is not really enough for big rigs.

    Last edited by Steamerpoint; 13th-July-2014 at 12:21 PM. Reason: Typo

  11. #11
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    Nice work but I've got to say I agree with DaveS and Steamerpoint, a mast thwart with a hole in and a mast foot attached to hull is so much simpler. I understand your reluctance to permanently attach a mast foot to your boat, but it'll be just behind the front seat and it doesn't really get in the way at all. You can still get a full load in.

    Re Nimbus's comment about Old Town gunwales, I had the mast thwart of my 44 sq ft bermudan rig bolted straight to the gunwales of my Old Town Discovery 158 and it was fine. Got me home through a force 5 blow once (not brave, foolish - didn't study weather forecast properly). The outriggers where practically submerged the whole journey, loads of force and no problems with weak rivets etc.

    I love the engineering of No Idea's folding mast support, but keep in mind the old acronym KISS; keep it simple stupid. No offence meant, I didn't invent this acronym!
    Last edited by fredster; 13th-July-2014 at 12:37 PM.
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  12. #12
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    I have been using a 44 sq/ft rig on my plastic Venture Ranger for nearly two years and had no problem, or so I thought!
    When I built the big rig, it was suggested that I beef up my gunwales and when I started adding the extra rivets, I noticed that one rivet close to the mast thwart had already pulled the skin hole. The gunwale was already 1cm above where it should be! I do tend to sail quite hard though.

  13. #13
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    Quote Originally Posted by fredster View Post

    Re Nimbus's comment about Old Town gunwales, I had the mast thwart of my 44 sq ft bermudan rig bolted straight to the gunwales of my Old Town Discovery 158 and it was fine. Got me home through a force 5 blow once (not brave, foolish - didn't study weather forecast properly). The outriggers where practically submerged the whole journey, loads of force and no problems with weak rivets etc
    Its not a problem if the mast goes through the thwart and in to a foot, but clamping solely to the gunnels is not the best solution. If you've ever built ( or seen built) one of these you'll know how little there is holding it all together. This is why we drill holes through the hull to lace in our airbags...
    Anyone can do that with two blades...

  14. #14
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    Ah, I see what you meant now, apols. ...and agreed, that is a lot of force if solely on the gunwales.
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  15. #15
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    Quote Originally Posted by Steamerpoint View Post
    I have been using a 44 sq/ft rig on my plastic Venture Ranger for nearly two years and had no problem, or so I thought!
    When I built the big rig, it was suggested that I beef up my gunwales and when I started adding the extra rivets, I noticed that one rivet close to the mast thwart had already pulled the skin hole. The gunwale was already 1cm above where it should be! I do tend to sail quite hard though.
    I'm not sailing my Ranger as you know.. But that was one of my concerns watching you steaming along on YouTube Steamerpoint was the load on the gunwhales. My boat has been popping rivet heads in just normal everyday use, I have been replacing them with plastic raw plugs and stainless screws. Which is working just fine. Part of my rivet problem I believe is salt corrosion with the poor quality material of the rivets Venture used?

    Bernie..
    I agree with fixing a mast foot to the floor is the best way.. I'm sure there is an ingenious way of fixing something more discreet to the floor which in turn a mast foot can be fixed to..if you see what I mean. So the mastfoot can be removed when not sailing.

  16. #16
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    Quote Originally Posted by bhofmann View Post
    .....So now I'm left wondering whether to shorten the posts so that the sail can come down further, or to trim the sail to shorten it. I'm also not sure about the size of the sail. I think it might be a bit too big. I'm open to suggestions and advice now.

    Mr Hofmann, Unless I am mistaken, you have asked 3 questions.

    Should you shorten your posts?

    Should you shorten your sail?

    Is the sail too big?

    In My Humble Opinion...

    Your mast is too far back. It needs to go slightly nearer the front. If its too far back, it wont tack properly. Mine is currently level with the front of the front seat.

    Ive built my arms so that they form an equilateral triangle. My arms are the same length as the canoe is wide - minus a bit as they dont quite meet in the middle.

    Have you considered mounting them on the front arm of that ourtrigger you have built? My arms are 1 1/2 x 3 studding from B and Q at 2.40 each and are the full 8 ft length. Having watched you use my outrigger on your canoe, I can state that this size will work for you.

    From practice, I believe I need 36 inches under the bottom of the sail if I want any chance of keeping my hat on. With this in mind I would shorten the sail to suit.

    I would also remove some of the leech if it has sail batons fitted so that I could use it without the batons and be able to wind the sail round the mast to store it and reef it.

    If I cut some off the leech, I would fold the edge over a length of carpet tape, then zigzag stitch it with my household sewing machine.

    I am of the opinion that if the mast isnt too big for you to balance, then the sail isnt too big if you can infinitely reef it. Dont forget that you have an extra foot of mast height over anyone who plonks their mast on the canoe floor.

    I am currently running 60 square ft of main, plus a spinnaker if the wind speed is slow.

    Mast loading...If you run 16 ft of mast from your canoe floor...
    If you stand your mast on the canoe bottom and support it at the thwart - 12 inches off the bottom, you have 15 ft of unstayed mast.

    If you stand your mast on the thwart, your mast now only needs to be 15 ft tall.

    If you support it 2 ft above the thwart, you now only have 13 ft of unstayed mast, which is a hell of a lot stronger than mounting conventionally.

    Other snags....

    Boom....
    I have used a piece of inch diameter curtain pole on occasion. It will work, so long as you sheet - run the rope from the connector you use to connect the back of the sail to it. Currently, Im using another cut down windsurf mast.

    A kickstrap is nice to have, but will stop the sail hanging out over the front if you drop it in a hurry.

    Sheeting....

    Main sheet is the bit of string you use to pull in the mainsail - not the bit of cloth the sail is made of.

    I run my mainsheet back through the back grab handle, then up to the sail.

    To get the sail to set properly if you arnt using a boom, the sheet should point to the middle of the front edge of the sail.

    Tell me if that doesnt make sense.

    Unless there is a fault with your canoe, your gunnels are unlikely to fall off. Most of us have our thwarts, leeboard thwarts, seats, carrying handles, painters, throw ropes and all sorts tied to them.

    Ive now thrashed mine for over 500 miles under sail with only one popped rivet, which I damaged ratchet strapping my canoe to the roof of my car through the grab handle.

    Please continue to post pics of your progress as I am really interested.

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