FG canoe repair

[roystr]

the wife found a canoe about 17' long,with 3 or 4 cracks going through the hull. do i just sand them all at a angle,and epoxy FG over them? that dont sound very stiff to me.i have 4 inch tape from another boat that didnt get built yet. will that work? also,the 2 spreaders in the middle are gone. any idea how i figg. out how long they ought to be when i make new ones? to spread out the center of the canoe?
i plan on yanking all the aluminum,decks,rails and seat brackets,and make new ones from wood. but i have no idea how wide the boat ought to be at the two center spreader bars. any idea folks?

thanx

roy

[ 08-09-2004, 09:14 AM: Message edited by: roystr ]

[Bruce Hooke]

The approach you plan to take for repairing the cracks sounds good. The repairs should, of course, be applied on the inside of the hull to keep the outside smooth. How sturdy the repair is will depend on how much cloth and epoxy you apply. If you build up as much thickness as is in the hull then it should be just as strong as the hull. The 4" tape you have should be fine. The only disadvantage of tape over cut strips of cloth is the edge of the tape tends to make a small ridge, which is more work to sand off aftewards if you are going for a nice smooth surface. It is better to use fiberglass cloth or tape that is designed to work with epoxy rather than polyester resin.

As to the thwarts (that's the proper name for what you are calling "spreaders"), if you can identify the make and model of the canoe then you may be able to get the thwart lengths from the manufacturer. They may even be willing to sell you replacement thwarts. If that is not an option then you will have to make your best guess based on what you can see of the hull shape.

Low cost fiberglass canoes are generally somewhat flimsy and crack rather easily. I suspect this may well be what you have given the number of cracks it has and it's general condition. With that in mind you may not want to put lots of work into replacing parts that are not broken or missing.

[Ian McColgin]

First I'd flex the gunnels in and out a bit to see how the cracks move. If they don't move much, I'd leave that repair till last. If you start there, skuff the inside and glass in some tape there. Then, if you're at all careful, you can make a little very shallow depression outside and fill in the trough with some glass - maybe not a whole width of tape but something. Sand the high overlaps on the outside when done.

If these are all fore and aft cracks and are concentrated on the very bottom, this might be a good time for a bit more beef on the bottom. Then you'd use glass cloth and cover at least to the turn of the bilge.

Anyway, on the the thwarts and gunnels. Rip off the aluminum. At the bow and stern are the breasthooks (micro decks) that in traditional construction hold the sides together. A natural grown fork makes the best but you can just use a plank with the grain athwartships. You can either let the inwhale (inside the hull part) of the gunnel run alongside that to the stems or can make the inwhale come up and just notch into the breasthooks, your call.

Even if the boat originally had only two thwarts, I'd rebuild with three.

To start, make a couple of temporary outwhales perhaps 3/8" x 1-1/2" to run bow to stern on each side. You'll need many many clamps. At least one every 18" to 2". Gonna need them anyway. A few at each end need to be C clamps but along the center concave curve of the hull you might get by with light bar or even spring clamps.

Clamp on these outwhales and then flex the gunnels apart at the center by hand just to take a look. Once you know the general size, make a temporary center thwart of a beam laid across the gunnels and clamped to the gunnel. You may need to add some clamped on blocks pushing against the inside of the gunnel. Move this out a bit at a time to see what looks best. If you've gone too far, the bottom with get a bit concave from the outside. Goal is bottom either slightly concave or dead flat. Your call.

Look at some canoes to see where the bow and stern thwarts go. They are the same distance from their respective stems. You need enough room that the stern paddler can either sit at the seat in the stern or can kneel and still have room. The bow seat goes just ahead of the bow thwart so there need also be room for the bow paddler to kneel ahead of that. The two center bays between the three thwarts are a bit smaller than (when added together) half the length. In other words, stem to either bow or stern thwart is a bit more than 1/4 length of boat, sorta.

With the center temporary thwart in place, the gunnel should be concave amidships but should grow a little convex as it gets to the ends. Fiddle the bow and stern thwarts in and out to see if you need to give a little push or a little pinch to make the whole hull just lie down nice and fair. It will feel right.

Once you like it, measure everything with care and mark on the hull where the thwarts go.

I think it easiest to fit the breasthook last inside a full stem to stem inwhale. Measure and fuss with beveling the ends so the two sides will meet nicely. Even as you're practice fitting with the thwarts out, the length of the gunnel is the same regardless of curve so it will fit except that the more the gunnels are spread, the more of a V shaped gap (open end in the boat) will appear at the stems. You can hide that later.

Make your inwhales and thwarts (remember to deduct for inwhale thickness) and glue those five sticks up as a unit. Epoxy can be slippery and you may want to temorarily tack screw the inwhale in place from the outside so they don't slide about. Same with the thwarts. But the many many clamps will do most of the work.

Do all your gluing with the boat upside down unless you really love grinding off epoxy drips.

Next the outwhales. Just glue and clamp one more slat outside and you're done.

If you want it to look really nice, it can be tapered. Even though this produces a small grain run-out problem for the finish - easily solved by a really penetrating varnish job - I like to just let the outwhale rise above the gunnel at the bow and stern and then plane to fit after the glue is dry. Easy to get a clean sweep that way. Plan from amidships out or the grain will run away from you and split.

Final gunnel step, the caprail part. This will add strength to keep the curve nice. Just glue a piece flat on top spanning from inside inwhale to outside the outwhale.

When this is dry, make and fit the breasthooks. If the gap in the inwhales annoys, you may rhasp that out so that the line of the inwhale bevels to nothing and make the breasthook fit that. Or cut a wee V wedge and make a complimentary micromini breasthook. Or glue a penny over it.

G'luck

[roystr]

thanks alot for the tips. yep,it had 2 thwarts in the middle(i can see where they went),and two seats for n aft. how thick ought the inside gunnel be in order to hang the seats from them? as opposed to riviting them to the sides?

the thing prob aint worth a dime. but it will give me practice doing several things on one boat. thanxs again,

roy

[Ian McColgin]

I'd suggested 3/8" for both inwhale and outwhale so that total gunnel would be over 3/4" - more like 7/8" - counting the hull sandwiched inbetween. This may actually be too hefty and you should scale back to 1/4" whales. But I know alot of these glass canoes are pretty flexy flimsey and a little extra rigidity at the gunnel will help.

Either way is abundant to hang the seats from. Easiest just to rivit or screw verticle posts to the inside of the inwhale and carry that down without touching the hull. Look at some old boats for how to do this with risk of splitting out the wood. There's a lot of ways here.

[roystr]

thanx again ian. i am in the process of building a stand to work from. but with a bad back,itl prob get done next year.LOL

this building thing looks like fun,and being disabled,will get my backside out a the chair.

thanks for the help,and we shall see where it goes from here.

roy

[Ian McColgin]

Ah Roy, while I do not have a bad back I am a great believer in getting the work to a comfortable height.

Any job worth doing is a job worth sitting down for.

I have made quite a variety of rolling seats, stools and creepers. One of my favorites which I later saw independently trumpeted by Bruce Bingham in one of his most wonderful books, was a staging creeper. Just a short plank on rollers shaped to stay with the staging planks. Absolutely the nuts for long hull repairs and surfacing jobs and easily adapted to a creeper when doing a plank repair and dutchman below the turn of the bilge.

G'luck

[ion barnes]

Ah, a familiar tale. No kidding. My other half brought a 16' canoe that she thought she could carry around herself, not accounting for the size and windage when lifting onto the roofracks !

It had a couple of cracks too, though you did not mention the location, these were from the gunnels and down the sides about six inches. When I stripped the plastic wales off, you coud see that the screws for the wales had fractured the very narrow edge and probably later, someone tried to empty the canoe of collected water by lifting one end and the boat tried to fold up!!.
Hence the cracks.

I solved the problem with 1/2 PVC pipe fastened to the gunnel edge and glassed over the pipe and down to just below the tears. Glassed the entire lenght of the hull, and yes it took some time to smooth the exterior, but it is bullet-proof now and will not buckle! Ever!

As for the thwarts/speaders; when the hull is laying upright on a couple of sawhorses, say about 1/4 length in from each end, measure your distances without pulling on the hull. Put the thwarts in first. That will stablize the hull and then you can fit the seats.