Advice on repairing/maintenance of fibreglass canoe hull

Hello, new user and new canoe enthusiast here.

Yesterday I bought a second hand fibreglass canoe. My aim is to take out my wife and son on short day trips on tranquil waters for a bit of a paddle. The rest of the time the canoe will be stored at my house under a roof (dry).

I’ll start by saying I know basically nothing about maintenance of a canoe and I’m not very knowledgeable about DIY.

The canoe I bought is a 16ft fibreglass Roseco (Australian manufactured) canoe built around 1985. I took it out on the water today and it was fantastic. The fibreglass shell looks to be in great condition, however there is some damage to the gel coat (I think that’s what it is?) on the hull, and some spider cracks and splintering on the inside. I am currently concerned about the hull - the inside can wait. I am looking to get the hull fixed up for as cheaply as possible.

Here is the canoe with my son looking very happy about it:

There are some cracks, holes and splinters on the hull. Here are some pics:

There are also these small nicks on the bottom, I think they may be from stones?

Firstly, I think that this damage would not really effect the use of my canoe, and I could leave them if I wanted? If someone could clarify that would be great.

However, I am keen to fix the hull up, as I think it would look nicer and perhaps last longer, I’m not sure.

From some googling and reading forums, here is what I think I should do:

  1. For the holes and larger cracks I should fill them with something called Bondo (??) or use a gel coat repairer (something like this: I could use this but I think it is expensive:

  2. For the spider cracks I can ignore them or perhaps use this:

  3. I could re-do the gel coat, however that would be a lot of work and expensive, and probably beyond my skill level. The majority of the coat is still looking good, so instead I think I should paint the hull with a marine paint like Rustoleum: I’ve read that you should use topside paint on Canoes as they are not in the water long enough to require underside paint. Is that correct? One person said that you can just use paving paint on canoes to save money? Something like this: Would that work?

Some advice from you canoe pros would be appreciated!



How much time and money do you want to spend? Sand the entire boat patch and fill cracks and holes then paint with two part poly paint?

Never saw an Australian canoe, it’s kind of pretty! You didn’t say how much you paid for it, but around here 30 year old fiberglass canoes that have survived this long typically sell for anywhere from $100 to $300. I just rehabbed a $40 Sears canoe with $75 worth of parts and sold it for $175, not exactly a profitable venture, but it kept me busy and the canoe will survive a few more years. I think your proposed plan of attack is appropriate, (bondo, light sanding and a once-over with a marine paint. The canoe should serve you well, none of the issues in your pics look very serious.

First, forget about trying to re-gel coat the whole canoe.

Filling, fairing, sanding and painting is an option, but paint adds weight and will scratch off. The scratches won’t show too badly if you use a paint that closely matches the underlying gel coat.

You are correct. You can use a topside paint on the hull bottom as long as the canoe is not sitting in the water for a long period of time. If you want to paint the boat, I have had good luck with the one-part urethane products Interlux Brightside and Pettit EZ-Poxy. These are both one part polyurethanes that are easy to apply. Just roll the paint on with a foam roller and immediately tip out any little bubbles and other irregularities using a disposable foam brush. Typically at least two coats are required.

Personally, I don’t think the boat looks nearly bad enough to warrant the expense and effort of painting. I would forget about the spider cracks. Any divots can be filled using either gel coat repair putty or Bondo. Both are basically a polyester putty activated with a MEK peroxidase catalyst. I would probably spring for the putty since you can usually get it in an ivory color that will better match your hull. If the color match is not close enough for your taste, you can paint over the repaired areas using something like an automotive touch up paint.

The last photo you posted suggests gel coat hydrolysis blistering. The small dark areas may represent blisters that have broken. The cure for gel coat hydrolysis is often worse than the disease. I would just clean up the dark areas and either apply a bit of paint or repair putty.

Thanks, this is all great advice. I realise that it is not totally necessary but I want to paint the hull anyway. I will use expoxy putty to fill the small holes and chips, I will sand it down with wet and dry paper, then I am going to paint it with a white gloss epoxy enamel paint. It will cost me about $80 AUD and it will get the hull looking fabulous and it should make it last longer.

Thanks for all the advice.

I suggest you find several publications by West Systems Epoxy. These 10-20 page guides will introduce you to everything you could possibly want to know about repair techniques- surface prep, materials including cloth weights, biaxial cloth, triaxial cloth, epoxy, catalyst, various fillers, thickeners, and the curing process. The vacuum bagging technique can produce a very smooth surface.

There is much to learn but the guides break it down to very simple, small parts.

Detailed knowledge such as the following can save you alot of time.

Polyester resin, though economical, may not bond as well compared to epoxy resin. Ounce for ounce epoxy resin gives much better adhesion. You can sand all you want, but if you rub in surface chemicals created by the natural degradation of polyester resin., there will be an adhesion problem. So you should wipe the area down with a particular kind of solvent first.

Those blisters are going to come right back unless you clean them out with a high pressure spray.