Soft Fiberglass at back of canoe


so i have a canoe that has the flat back to it so you can mount a small engine onto it

now bewteen there and the actual back seat there is a section of fiberglass that kind of looks like you could sit on it as well

only thing is its super soft and very brittle, was purchased this way

anyone know the best way to deal with this?

or if this is normal?

Don’t sit on it
Someone did .

Fiberglass patch to reinforce is needed.

definitely wont be sitting on it

the thing is its the entire back side, have no idea what its called but it does look like a back seat made out of fiberglass

the entire thing is soft to the touch when i press on it

patch the whole thing

I’m thinking it’s a float chamber
Float chambers are often built into the ends of composite canoes. A conscientious builder of a square-back canoe would put a much bigger float chamber at the rear to compensate for the weight of an outboard motor in case of a capsize or swamping. I’d have to see a picture or get a more-detailed description of the thing to be sure, but that seems likely to me.

How’s the condition of the transom? Is that nice and solid? The need for strength there is more important. There’s often a thick sheet of plywood inside the transom of a fiberglass boat, and if water gets into that wood via tiny cracks, you can end up with a soft, floppy transom that’s not suitable as a motor mount.

picture of my canoe
below are two pics of my canoe

Yep, that’s a float chamber
There may be a big block of styrofoam in there, or it may be empty space (air). If it’s flexible, especially if it’s “crackly”, an extra layer or two of fiberglass might be a good idea. There are other people here who are far more expert than I when it comes to fiberglass work, but I doubt if the method is highly critical in this case.

ok so basically its safe to say that it would be a good idea to re-fiberglass on top of the cracking thin fiberglass??

I think so
It also looks like the float chamber is not well-attached around all of the edges (it looks pretty well attached along the front, just not elsewhere). Therefore, wrapping the new fiberglass onto the hull at the edges of the float chamber would probably be a good idea. Ask the experts here if you need to sand down to bare fiberglass before applying new material. I don’t know if that multi-colored coating is paint or excess resin (looks like a chopped-fiberglass layup that’s sprayed onto a mold with resin, rather than fabric with resin worked in by hand).

thank you
awesome thank you to those that replied, much love!

make sure you don’t seal in moisture
I am a little concerned that you may have water inside; when it gets soft and brittle like that I suspect rot. If the cracks allow moisture through, it could be a bigger problem. Let the boat sit upside down and slanted so that water would run to the corner for a day or two and the press around it and see if any water drips out of the crack. If it does, I would make a small opening (as in drill a small hole or pry the crack open slightly) and let it drain for a few days before patching.

Fiberglass rots when wet?
Many fiberglass boats sit in the water for months or even years at a time (not paddle craft, but motorboats and sailboats). Never heard of the material “rotting” when wet.

However, removing moisture from the float tank before sealing is still a good idea. In fact, most such tanks already have a plug that can be pried out to facilitate drying things out inside in the event of hull damage (not this one, from the looks of it). For what it’s worth, once all the water that can be drained is removed, it’s far more effective to warm up the tank than to hope for more drainage. Even putting a 100-watt or larger light bulb close to the tank for a day or two would be far more effective than continued drainage (even better would be to wrap than end of the boat with something to contain the bulb’s heat in that area and if there’s a block of styrofoam in there, you’d want to apply heat from all sides).

maybe rot isn’t the right word

– Last Updated: Jan-23-14 6:39 AM EST –

but when fiberglass gets a film of lake water under it in a spot like that, things grow and the effect of it is often like "rot". It gets soft end easy to break. I don't know if it is breaking down faster or what the issue is, but it is much the same as fiberglass left in a bog; somehow that is different than just in the water. I had a Sears fishing boat that suffered badly from it.

EDIT - Got curious and looked into it more. There are lots of shops and products that refer to "rot" and are most commonly fixing plywood (see other poster remarks below) and/or gel coat, but it turns out that prolonged exposure to moisture does indeed begin to break down the polyester, which is the resin used in most manufactured glass boats. Gel goat protects the exterior, but they don't protect the inside. The woven fibers technically do not rot, but if the resin breaks down the effect is the same.

might be plywood under there …

– Last Updated: Jan-22-14 10:58 PM EST –

..... the top coating is sprayed strand fiberglass and resin ... chop gun construction like the rest of the canoe .

The seat like bulkhead is serving 3 purposes I'll bet you . 1., as said it's a flotation chamber , 2., it's a structural reinforcing component for stern end to strengthen the stern because of motor use , and 3., it's a convenient platform to use .

Do a test to start out . Drill a couple holes in top area . One in the soft spot and the other near the edge . If wood comes up when retrieving the bit then you know there's ply under it .

My guess is it has the plywood and the ply has become deteriorated . In any case not a big deal to remove a replace if you want to , small job but a job none the less .

If you need some ideas and advice on how to remove and replace , just ask . In my mind it wouldn't hurt to have look see what's going on under there , might be lower transom problems as well which are more important to get fixed up .