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Thread: Hi! And a question about a mastfoot.

  1. #1
    Join Date
    Mar 2017
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    Netherlands, poortugaal
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    4

    Default Hi! And a question about a mastfoot.

    Hello everybody,

    First of all: i'm new on this forum. I'm from the netherlands (as you can probably tell from my spelling) and I'm pretty new in canoe sailing. I have had a pouch rz 85 folding canoe with a little sail and a jibsail, what a fun was that!! I had quite some experience with paddling Canadian canoes (mainly German gatz) but my house and garage were to small to store a big canoe. A folding canoe seems a good solution and the additional sail opened a new world, what a great way to cover greater distances and be able to use the wind instead of fighting it. After two years and a lot of trips and a lot of reading one this forum I decided that I wanted something more serious. I found a way to solve the storage problem and bought a old town discovery 169. (My 4 months old son already liked it on the water haha) I found a set wit leeboard, a rudder, a mast, big sail and jibsail in good condition for 30 pounds. The sails are about 40 sq ft. I'm going to make a mast foot out of oak but now come my question: I rather not want to bolt the mat foot on to the hull but I want to glue it with g flex. I also want to stiffen the construction with a mastbrace. Will the gflex hold with this size of sails? Of do I need to bolt the mastfoot?

    thanks for thoughts!

    Frank

  2. #2
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    237

    Default

    Hello Frank,

    Best of luck on this project. I would prefer to use good marine plywood instead of oak for what (in North America) is a mast STEP (step-foot: interesting similarities). 2 reasons:

    Plywood is dimensionally stable, thanks to the cross grain. If you glue it down it will not expand and contract like oak. That will help the epoxy hold.

    Plywood is not likely to crack; oak may or may not.


    If you glue down the step/foot with gflex, you will be stuck with its location unless you grind it off with great care. If you bolt it and wish to move it, the holes can be filled. If you bolt it, I would use a good semi-flexible caulk between step and hull, something that you can scrape off later.

    Even if you glue the step with gflex, adding bolts is 'best practice.' If you decide to use only gflex (good stuff) make the step relatively large to increase bonding area.

    I am working up a canoe right now, will start reporting on it in the next day or so. One of the sail rigs will be an Opti sprit sail converted to a balanced lug.

    My best,

    Bob


    Quote Originally Posted by Frank-h View Post
    Hello everybody,

    I'm going to make a mast foot out of oak but now come my question: I rather not want to bolt the mat foot on to the hull but I want to glue it with g flex. I also want to stiffen the construction with a mastbrace. Will the gflex hold with this size of sails? Of do I need to bolt the mastfoot?

    thanks for thoughts!

    Frank

  3. #3
    Join Date
    Mar 2017
    Location
    Netherlands, poortugaal
    Posts
    4

    Default

    Hi Bob,

    Many thanks for your massage! Good idea to use marine plywood, i probably go for that. If i varnish the oak, does it still expand and contract and/ or crack?

    If i bolt the maststep on the hull, i have to drill holes in the hull. I'm afraid that the holes will leak. How do i prevent it from leaking? With the caulk? (Caulk is that stuff u use for sealing bathrooms right? Just to be sure)

    Removing and repositioning the maststep wouldn't be my biggest concern, the best place is right after the frontseat right? So the biggest reason to use caulk and bolts instead of only gflex is the fact that gflex is a pain in the *#$ to remove when repositioning the maststep instead of the fact that it wouldn't hold, right? Ofcourse adding bolts is stronger but if it isn't necessary than i use Gflex with a bigger maststep out of marine plywood. If there is a certain chance it will pop off in strong winds, i will bolt it down to the hull.

    Good luck with your project Bob, i will look for your thread!

    Cheers!

    Frank

  4. #4
    Join Date
    Jan 2016
    Location
    Redhill, Surrey
    Posts
    267

    Default

    an idea here for strengthening the foot-to-hull joint without bolting:

    http://www.solwaydory.co.uk/articles...xpedition-rig/

  5. #5
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
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    Default

    Good suggestion. Profiling the botom of the foot is always worthwhile.

    Bob

    Quote Originally Posted by aannddyyhh View Post
    an idea here for strengthening the foot-to-hull joint without bolting:

    http://www.solwaydory.co.uk/articles...xpedition-rig/

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

    >

    <How do i prevent it from leaking? With the caulk? (Caulk is that stuff u use for sealing bathrooms right? Just to be sure)>

    A flat or oval head screw coming up from the bottom won't leak if it is adequately tight. A tiny bit of caulk under the head will do no harm.

    <Removing and repositioning the mast step wouldn't be my biggest concern, the best place is right after the front seat right? >

    Since I keep tinkering with my canoes, I do change step locations....

    Placement of the mast (and leeboard) are related to the size and shape of the sail(s). You can find a whole lot on the web about CE (center of effort) and CLR (center of lateral resistance), some of it misleading. But in general it is good if the 'combined CE' of your sails is near or just forward of the middle of the hull. In turn, it is good if the leeboard(s) are near the middle. And establishing that rather depends on figuring out the fore-and-aft balance of your hull so that when sailing the hull is trimmed 'on its lines.' There are always a few compromises required.

    That isn't a very satisfying or quick response, I'm afraid. If you measure and send a sketch of your sails, I am sure folks here will help refine an answer.

    A lot of things can be made to work at some level, but if you are going to make an effort to rig the canoe, you might as well try to optimize things. If your big sail is 40 sq ft by itself, it may be sufficient without the jib.

    <Good luck with your project Bob, i will look for your thread!>

    Thanks! I need luck with the weather today.

    Bob

  7. #7
    Join Date
    Dec 2006
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    2,441

    Default

    Although my sail is a standard Endless River oil, I used contact adhesive to glue on a thin closed cell foam mat to the bottom before glueing that to the hull of my canoe. The theory being the hull will flex and the foam mat will absorb the flex a lot better than a solid wooden block.
    Cheers
    Tim


    Paddles a Prospector

  8. #8
    Join Date
    Sep 2014
    Location
    Cumbria
    Posts
    1,260

    Default

    You'd be absolutely amazed how good a hold 3M dual lock velcro gets. I can lift my whole boat off the ground by the mast foot. If anything, it's even stronger laterally.

    Mine is two bits of ash clued together with polyurethane adhesive and profiled to the hull shape on the bottom. The dual lock has 3M VHB adhesive on it, this is what's holding it to the hull. It didn't get such a good hold on the wood so I clamped it down with some polyurethane adhesive.

    No holes drilled, mast foot is removable (although you have to stand in the boat and give it an almightly heave to do so). Worth a try before you do anything permanant.



    "I'm not getting in a boat which is DESIGNED to go upside down."

  9. #9
    Join Date
    Mar 2017
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    Netherlands, poortugaal
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    Default

    Thanks Bob, Tim, aannddyyhh and Stinkwheel for your answers.

    @ Andy: i looked already a lot on the Solway Dory website, very useful. Just was wondering if everybody did it the same way they do it.

    @ Stinkwheel: how big is your sail?

    @ Bob: Wow! I din't realise that finding the right place for the mast and leeboard would be so difficult with terms like centre of effort and centre of lateral resistance. My idea was to fit the mast for just the mainsail and on a lowwind-day i can add the jib sail. Now i understand that finding the right place for the mast depends also on if i am mainly going to use one (main) or two (with the jibe sail) sails. But i'm probably not the only one who sometimes use one and the onther time use two sails. In such case the mast and leeboard location is not allways ideal. Say you take the combined centre of effort and mainly sail only with the mainsail, the boat is slightly out of balance.. Same is when you use the CE for just one sail and then sail with twe sails. Will that make such a big different for a guy like me, who sails maybe 4 times a year? With the combined CE the mast will come further towards the centre of the boat, not sure if i want that. I don't have the sails yet, the first weekend of april i pick them up. Than i can measure the sails and decide what i'm going to do.

    If i'm making a maststep out of marine plywood, should i varnish it? or cover it with epoxy?

    Chears!

    Frank
    Last edited by Frank-h; 16th-March-2017 at 02:43 PM.

  10. #10
    Join Date
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    Default

    Nowhere near 40 sqare foot. Biggest one I've used is a miracle jib sail downwind.

    I was more saying that dual lock really gets a hold, so whatever size your mast foot is, it would probably attach to the hull pretty securely using more or less of the same stuff without having to drill any holes. Once it's "clunked" into place, I think you'd probably damage the mast or mast thwart before it detached. To get it off, you have to pull up on it.

    They quote a shear strength of 40 Newtons per sq cm.
    "I'm not getting in a boat which is DESIGNED to go upside down."

  11. #11
    Join Date
    Mar 2017
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    Default

    Quote Originally Posted by Bob Cavenagh View Post
    >

    <How do i prevent it from leaking? With the caulk? (Caulk is that stuff u use for sealing bathrooms right? Just to be sure)>

    A flat or oval head screw coming up from the bottom won't leak if it is adequately tight. A tiny bit of caulk under the head will do no harm.

    <Removing and repositioning the mast step wouldn't be my biggest concern, the best place is right after the front seat right? >

    Since I keep tinkering with my canoes, I do change step locations....

    Placement of the mast (and leeboard) are related to the size and shape of the sail(s). You can find a whole lot on the web about CE (center of effort) and CLR (center of lateral resistance), some of it misleading. But in general it is good if the 'combined CE' of your sails is near or just forward of the middle of the hull. In turn, it is good if the leeboard(s) are near the middle. And establishing that rather depends on figuring out the fore-and-aft balance of your hull so that when sailing the hull is trimmed 'on its lines.' There are always a few compromises required.

    That isn't a very satisfying or quick response, I'm afraid. If you measure and send a sketch of your sails, I am sure folks here will help refine an answer.

    A lot of things can be made to work at some level, but if you are going to make an effort to rig the canoe, you might as well try to optimize things. If your big sail is 40 sq ft by itself, it may be sufficient without the jib.

    <Good luck with your project Bob, i will look for your thread!>

    Thanks! I need luck with the weather today.

    Bob

    Thanks Bob, Tim, aannddyyhh and Stinkwheel for your answers.

    @ Andy: i looked already a lot on the Solway Dory website, very useful. Just was wondering if everybody did it the same way they do it.

    @ Stinkwheel: how big is your sail?

    @ Bob: Wow! I din't realise that finding the right place for the mast and leeboard would be so difficult with terms like centre of effort and centre of lateral resistance. My idea was to fit the mast for just the mainsail and on a lowwind-day i can add the jib sail. Now i understand that finding the right place for the mast depends also on if i am mainly going to use one (main) or two (with the jibe sail) sails. But i'm probably not the only one who sometimes use one and the onther time use two sails. In such case the mast and leeboard location is not allways ideal. Say you take the combined centre of effort and mainly sail only with the mainsail, the boat is slightly out of balance.. Same is when you use the CE for just one sail and then sail with twe sails. Will that make such a big different for a guy like me, who sails maybe 4 times a year? With the combined CE the mast will come further towards the centre of the boat, not sure if i want that. I don't have the sails yet, the first weekend of april i pick them up. Than i can measure the sails and decide what i'm going to do.

    If i'm making a maststep out of marine plywood, should i varnish it? or cover it with epoxy?

    Chears!

    Frank

  12. #12
    Join Date
    Dec 2012
    Location
    Pennsylavania USA and Ontario Canada
    Posts
    237

    Default

    Hello Frank.

    I will try to answer your questions, not here but in the thread on some canoe sail rigs that I am posting to in installments.

    Bob

    >@ Bob: Wow! I din't realise that finding the right place for the mast and leeboard would be so difficult with terms like centre of effort and centre of lateral resistance. My idea was to fit the mast for just the mainsail and on a lowwind-day i can add the jib sail. Now i understand that finding the right place for the mast depends also on if i am mainly going to use one (main) or two (with the jibe sail) sails. But i'm probably not the only one who sometimes use one and the onther time use two sails. In such case the mast and leeboard location is not allways ideal. Say you take the combined centre of effort and mainly sail only with the mainsail, the boat is slightly out of balance.. Same is when you use the CE for just one sail and then sail with twe sails. Will that make such a big different for a guy like me, who sails maybe 4 times a year? With the combined CE the mast will come further towards the centre of the boat, not sure if i want that. I don't have the sails yet, the first weekend of april i pick them up. Than i can measure the sails and decide what i'm going to do.

    If i'm making a maststep out of marine plywood, should i varnish it? or cover it with epoxy? <


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