Thread: Quick Canoe Sailing Potential - No such thing as bad questions

What is the problem you are trying to get around Clinton?

My ignorance.

I'd like to learn the underpinning theory. I've used epoxy before, but never cloth and epoxy encapsulation, nor do I know enough about material strength being affected by the techniques yoy use.

I particularly do not like following directions without knowing the underlying reasons.


I am also frustrated by not understanding enough to be able to be able to add a mast and keel case to your design, and feel that if I learn enough, I'd be able to start to experiment.

That defines the question really nicely clinton!

I can run through the ways I handle it with the strengths and weaknesses.

The biggest load to deal with is the load of the mast. However the limit of the load the mast will carry is the stability of the boat. My boats are all monohulls and quite light, so I can use unstayed masts without too big a weight penalty using basice materials like timber.

An unstayed mast needs to be supported at two points. The partner and step.

If the load is large because the two points are close together or the boat is large or a multihull or has wings then the most practical way to handle the load of a freestanding mast is to carry it in some piece of horizontal plywood that is bonded to a large area around its perimeter.

The Goat, the OzRacer (formerly the OZ PDRacer), Beth all carry the loads in this way. Beth and the OzRacer through the decks and hull bottom. The GIS through the seat top and hull bottom.

A big horizontal sheet of ply can take enormous load if it doesn't buckle and the job becomes to spread the load into the mast in a way that won't dent it.

The centrecase has a problem where it can break off the bottom of the hull easily if the centreboard hits something hard. So you need not only the normal bonding area to the bottom of the boat, but you need to deal with the loads at the back of the centrecase, which is where it will usually break off if the boat hits something when going fast.

It sounds dramatic, but if enough bonding area of the centrecase to the floor at the back of the case then that reduces the risk to nothing. The GIS and BETH have a bulkhead there and the OzRacer has a timber frame going across the boat with a ply gusset connecting it to the back of the case.

The drop in sailing rig works without any of these things because the stability of the canoe is so low. If you added a leaning plank or wings to the canoe, or turned it into a catamaran, the mast would have to be much stronger which would require the partner to be a lot better attached to the hull than it currently is.

Increasing the sail area as Paul has done, doesn't change much as it means the boat will lie down (capsize) in lighter winds than it did before - the mast just has to make the boat lie down.

If some thing like the existing drop in rig partner was used in a canoe sailed with more weight on the gunwale, you would probably need to ally it with a bulkhead to distribute the load into the hull.

The trick of course is to minimise the amount of structure required to pull this off.

Best wishes
Michael

Originally Posted by Clinton1

Bouancy bags in AUS is annoying me. One of my house bound activities was going to be an attempt to find a way to make them cheaply, at home.
I see no reason to spend as much on bouancy bags as the entire canoe...

Buoyancy bags are quite easy to make from PVC material and the right glue. I'll post some info on how to do it soon as I have a moment.

Ian

AJ,
your wine casks and water bladder solution is good... but I'd be paranoid about them failing when a few little kids are in the canoe. Although they would all be wearing life jackets, I can imagine the reaction from the parents if I had to drag them all to shore in a chain of scared little kiddies.
If it were just for me, I'd take this route.

Ian,
I would greatly appreciate that info.
A seperate thread, in order to make it easier for others to find/search would be a good idea, and would help a lot of other people as well. Looking forward to it.


MIK,
Its taken me a while to digest you last post. I think I've got it.

For example (forgive the lack of correct terminology!):

An efficient bulkhead spreads the load between the hull sides, allowing forces to be distributed, and allows the hull to maintain its shape.

It also allows you to take advantage of the fact that it can be a great place to put flotation material, or act as a storage 'locker', if you wish.

Instead of putting in a solid piece of timber, you can consider weight and either cut out the solid piece to remove material and hence weight, or take advantage of the stiffness of ply and its lower weight and use that.

If the ply has to span a long enough area, and the forces acting on it are great enough, then it can be strengthened by adding solid timber strips (the same as the gun/in wale).
Take it a step further and make the bulkhead into a box with solid strips, and you get a very stiff bulkhead (almost a torsion box), and a chamber for storage/flotation.
Make this box to be airtight, and you create a pressure vessel, so you'll need to add an air escape, for when it is going to heat up in the sun and expand.
I'd have to ensure that the joint between bulkhead and hull is able to accomodate the forces acting on it, so a 'liquid nails' glue line won't be sufficient, use an epoxy fillet and/or a strip of timber to strengthen the join.

De-clutter and economise the interior of the hull.

At the stern/bow, under the deck is an obvious place for a bulkead, but the 'properly constructed' deck should act to add stiffness in this area
Therefore, although this is an place that will not 'take up space', I might add weight to little effect (especially when considering where the forces that I'm trying to distribute will occur).
As for the secure storage, if its just going to be bouyancy bags, I can just add small glue blocks to the sides of the hull, and just use 'lacings' to secure the bags.

So, 'ideally' (according to my level of ignorance ):
I work out where the mast will be located, place the mast step, and then 'bracket' that with a 'boxed bulkhead' which allows the mast to 'drop in' and be freestanding.
The mast will wear away at the material where it contacts, so I might consider putting in a sacrificial piece of pvc pipe in here so the mast wears this and not the bulkhead/mast suppport.

I'd 'hope' that the bulhead can also act as a 'back rest' for when the canoe is just being paddled (by two people), and if I'm tricky enough I can add seat supports to the sides of the hull.

If I add a centre case, then the seat supports can run toward the rear of the canoe, and form part of the support structure of the centre case... which can also be joined to the bulkhead supporting the mast, e.g. a bulkhead that incoporates/ 'acts as' the mast support and the centre case structure.

In essence, the bulkhead incorporates the mast support and the centrecase. Although the centrecase may not extend to the top of the sides, I could always put a 'deck' on it, creating additional stiffness (a horizontal 'bulkhead'), and use the enclosed space for more bouyancy storage.

Not as light as your 'drop in sail rig', and not removable... but call it an exercise in removing my ignorance.

How's my thought process?

Clinton is wanting a separate post about gluing PVC but I'm wishing these posts were combined. So many threads to follow and I don't get here often enough. I guess we'll muddle through somehow, but hate to miss any of this.

How about a weather balloon? We used to use automobile inner tubes. I have watched air bags being made and know that they use radio frequency welding rather than glue. PVC pipe cement works about the same as the vinyl glue sold for mending swimming pool liners and is much cheaper. I think the wooden bulkhead might be simplest, cheapest and useful to stiffen the structure as well.

Paul,
If Ian does a seperate thread, I'm happy to cut and paste his post into here as well... if it is a seperate thread and titled/tagged well, a google search will bring it up so it is easy for people to find.
I think that making the info easy to find is important as I worked out that it would cost over $300 to buy commercially available'canoe bags' that can act as bouyancy bags. So, lets make a new thread, and put it in here as well.
I agree with you about the fact that there are too many threads to look at on this forum... its the curse of success... also called 'catastrophic failure'. There is such a lot of great info on this forum that I have difficulty searching and finding the info I know exists.
Too many great threads, too much info to search through... too little time and too little bandwidth.

I'll add a caveat to my last few posts.

I have purchased MIK's drop in sail rig plan. Great value for money, and whoever has bought MIKs' plans knows that it is a plan plus a 'tutorial in construction' in one. Fantastic.

The drop in sail also meets the philosophy behind the Quick Canoe... e.g. simple, quick, efficient and effective.

I don't like it though.

My reason is that I Iive opposite a bay that has hundreds of boats moored in it.
From power boats to fibreglass and plastic sailing constructions, to the old timber 30" sail boat with sculling oars secured to it (for getting into the harbour in nil wind).
Down the road is the sail club that seems to attract all the Moth sailors, and a bit further around from that is another sailing club that attracts the 'trailor sailer' with their Lazers and home built jobs.

So, MIK designed a Quick Canoe that fits a specific purpose. Cheap, easy, quick, servicable.
Just walking across the road has gotten 3 offers to buy it so far... 3 pieces of ply and some strips seems to equal a strangely attractive canoe.

I bought the GIS plan, and there is my spectacular, cheap, sailing boat.

Stuff that!

I want to walk across the road with the QC on my shoulder. drop it in the water, put up the mast, sail from Kogarah bay to Botany bay...and be doing it for under $600.

So, MIK's designs are great.... but I'd like to turn this QC into a sailing canoe that is light, able to be carried, and makes people say 'stuff buying that, I'll do it myself'.

Originally Posted by Clinton1

How's my thought process?

I am about as impressed as it is possible to be. I have some comments I want to add, but only in terms of small redirections - it is a pretty good summary.

Just horribly busy with stuff for the next day or so.

The "boat on the shoulder" idea was one of the criteria for Beth. Because I had owned light boats like scow moths, but they were impossible to carry because of width and bulk. I knew I could carry a canoe though.

My BETH worked out at around 70lbs (30kg) for the hull so in my 30s I was able to carry the hull on my shoulder. In my 50s ... not so much!

But the marketplace for a sailing canoe is as you say ... not to go as far as BETH ... but have good covering of distance regardless.

For a sailing boat rather than a paddling boat, I would rather add a bit more beam if it doesn't add too much more weight - more sailing stability and post capsize stabilty.

BETH is OK because of the amount of air tankage and sealed areas, but that adds some surface area that means a bit more sophistication in the structure compared to what the quick canoes should be about.

I wrote to Paul, who was thinking much along the same line as you clinton, that I would probably go for buoyancy tanks at seat level going up into the ends of the boat - it simplifies construction because they can be flat on top and the boat still look good and saves a bit of weight in terms of bulkheading and centrecase etc.

Strikes me that the RAID41 rig would go very close to about the right area with some taken off the bottom of the mainsail.

The comment you made about the Quick Canoe being "strangely attractive" made me chuckle. I might use it at some point in my writing!

Part might be that it just looks good because it has been built nicely ... and that blue is great too.

MIK

Thanks MIk...
I'll keep working on it and economise more.
Your plans seems to be about economy... and in my line of work, effectiveness, efficiency, and economy... = elegance. A much desired state... which seem to be what your plans are all about.

I'll work on the bouyancy tanks at seat level... there is a lot of potential there.

Years ago I ran a trout farm for a fellow who used the word "elegant" in exactly that same way...effectiveness, efficiency, and economy. A best solution for whatever the problem.

I've lost count of the times folks have said something like, 'You don't see them like that anymore" or, "What vintage is that?" In these hills people appreciate that sort of elegance. I've never had a better conversation starter. Part of the "vintage" idea may come from the fact that I used the cheapest plywood and have had to keep at it to keep water out of the plys with whatever epoxy bog I have a bit left from another job, all kept oiled with a mixture of linseed oil, turpentine and pine tar. I think the patina of use was part of what the judges at St Michaels liked when they awarded a second place ribbon for the boat. (They also saw it sail and were favorably impressed with the handling both in the harbor and out in the bay beyond the breakwaters).

Originally Posted by Clinton1

Ian,
I would greatly appreciate that info. (On making Buoyancy Bags)
A separate thread, in order to make it easier for others to find/search would be a good idea, and would help a lot of other people as well. Looking forward to it.

Have put up a separate thread on making buoyancy bags. Copy the info to here if you want.

Regarding finding the specific information you want within this forum (amongst the extraordinary amount and variety of information contained here):

"Advanced Search - Search within a site or domain:" in Google will often pull up lots of information about what you are looking for, many times you'll find someone else has posed (and had answered) the same question in the past.

https://www.woodworkforums.com/f169/d...5/#post1222885

Ian

Originally Posted by Clinton1

Its taken me a while to digest you last post. I think I've got it.

For example (forgive the lack of correct terminology!):

An efficient bulkhead spreads the load between the hull sides, allowing forces to be distributed, and allows the hull to maintain its shape.

Also imagine all the surface area the seat tops and bulkheads have with the hull.

It also allows you to take advantage of the fact that it can be a great place to put flotation material, or act as a storage 'locker', if you wish.

I agree if the flotation material is air. The epoxy/ply is completely reliable for keeping the water out. People do think of end air tanks as being a good place to store things - but it is a well known way of making the boat pitch more, losing a lot of speed, making it uncomfortable and wet. Best place for any real weight is near the middle of the boat. That's why racing sailors sit almost on top of each other as they cluster together.

Instead of putting in a solid piece of timber, you can consider weight and either cut out the solid piece to remove material and hence weight, or take advantage of the stiffness of ply and its lower weight and use that.

Yes ... sometimes the simple piece of wood can be lighter - because it is so simple. But when you combine seat, buoyancy, centreboard and spar support into the one structure it makes a lot of sense.

This also points out the advantage of the Drop in sailing rig .. it can't take a lot of load, but it is simple and removable.

If the ply has to span a long enough area, and the forces acting on it are great enough, then it can be strengthened by adding solid timber strips (the same as the gun/in wale).
Take it a step further and make the bulkhead into a box with solid strips, and you get a very stiff bulkhead (almost a torsion box), and a chamber for storage/flotation.

The "strips" are often not needed except for some of the function ... loads from sitting or from the spars. With spar loads, I usually put in a cutout bulkhead near the partner/step.

Make this box to be airtight, and you create a pressure vessel, so you'll need to add an air escape, for when it is going to heat up in the sun and expand.

It is often said, but I've never seen any lasting damage in the thousands of boats I've raced against. The first NS14 that was built for me had the decks glued on on a hot day in Sydney and the weather changed. The builder, Ian Bashford, came out and found the decks had been sucked down, or pressed down by about 50 mm - which is quite a bit of volume. No damage - he just drilled a little hole.

I used to put a small hole in the middle of my plastic inspection ports - but on reflection i have never, ever seen any damage from this phenonemon - so have stopped doing it. But usually I put the boat on the edge of the water before putting the lids on the inspection ports.

I'd have to ensure that the joint between bulkhead and hull is able to accomodate the forces acting on it, so a 'liquid nails' glue line won't be sufficient, use an epoxy fillet and/or a strip of timber to strengthen the join.

That' is pretty right ... but the areas involved from filleting in the tank top and side are huge so don't need any special arrangements. Generally the rules of thumbe for either timber cleats or fillets are correct for the plywood to plywood join being similar to the strength of plywood itself.

Liquid nails is useless - it just stretches under real load. fillets OR timber are the best way usually. One method is enough.

De-clutter and economise the interior of the hull.

Exactly - that is the motivation for every decision.

So, 'ideally' (according to my level of ignorance ):
I work out where the mast will be located, place the mast step, and then 'bracket' that with a 'boxed bulkhead' which allows the mast to 'drop in' and be freestanding.
The mast will wear away at the material where it contacts, so I might consider putting in a sacrificial piece of pvc pipe in here so the mast wears this and not the bulkhead/mast suppport.

Got it!

I'd 'hope' that the bulhead can also act as a 'back rest' for when the canoe is just being paddled (by two people), and if I'm tricky enough I can add seat supports to the sides of the hull.

Back rests can reduce stability as the body moves more with the boat increasing the effective height of the centre of gravity. If the body moves it compensates for heeling in an automatic way. At the same time a seat can be useful. I actually paddle beth kneeling Much better for keeping out of the way for sailing gear.

I suspect the seat back will have to be too far forward if by yourself and too far back if you are with another paddler.

If I add a centre case, then the seat supports can run toward the rear of the canoe, and form part of the support structure of the centre case... which can also be joined to the bulkhead supporting the mast, e.g. a bulkhead that incoporates/ 'acts as' the mast support and the centre case structure.

It might work ... generally I like a bulkhead at the back of the centrecase to prevent it breaking from the bottom ply at the back if the board hits something. With a bulkhead it will never break. This means it starts to be sensible to put a deck or part deck coming back that far to integrate the appearance of the boat. But you might be able to swing something else.

In essence, the bulkhead incorporates the mast support and the centrecase. Although the centrecase may not extend to the top of the sides, I could always put a 'deck' on it, creating additional stiffness (a horizontal 'bulkhead'), and use the enclosed space for more bouyancy storage.

Haha! Great Minds!

Not as light as your 'drop in sail rig', and not removable... but call it an exercise in removing my ignorance.

How's my thought process?

Rather good clinton, rather good!

MIK

Thanks MIK... I greatly appreciate the time yo put into your responses.
I think I'll have to take a few days to digest your answer.

BAD news... Friday was really windy here in Sydney, and I keep the QC upside down on a timber stack that I am drying... almost 2m high. The stack is on the concrete, beside the lawn.
The gusts moved the QC a little, so I struggled out and lifted if off to lay it on the grass, so that it would not fall onto the concrete.

Anyway, I could not do it well as I was standing on one leg (due tothe cast I'm in), I slipped, the QC dragged off one of the top boards of the drying stack, which kicked up and caught the QC right under the centre spreader just inside the hull, withe the QC dropping down on it.

The fillet of the centre spreader held, but the timber of the inwale split, and the split run down to the ply.

Repair job coming up, but it will be hard to keep it looking good.

Sometimes, patience is not my virtue. At least I didn't wreck my ankle though.

Glad you didn't hurt that new ankle of yours! With the QC .. can you post a photo ... there might be a nice way of fixing it with minimum hassle. MIK