How much fiberglass will prevent most damage to my ply or timber canoe or sailing dinghy?

How effective is fibreglass for preventing boat damage from impact – is thick fibreglass better than thin – hint – thin is almost as good as thick. But the reason and datapoints are interesting.

Eureka plywood canoe - preventing holes and damage from hitting rocks, stumps. Fibreglass and repairs

Hello! I’m from NW Florida and I’m thinking of building the eureka canoe for the creeks around here.

I’m just wondering how tough these things are as I’ll be using it in tight fairly quick moving creeks with plenty of stumps logs, trees, snakes and general peril and theres no doubt it will be hitting things from time to time :)

Sean

Resources
Method for fibreglassing large areas
Repairing damage to plywood and other light timber boats

Howdy Sean,

We have had really good results using very light woven glass cloth.  It adds very little weight compared to the usual fibreglass cloth that people use on their boats and offers much the same protection.

Like some recommend 4oz or 6oz glass.  We go way lighter – because it is easy to put on and saves a lot of weight.

I would recommend 2oz or less.

The plywood should be 6mm (1/4″). If you have the dollars make the main hull panels (2 sheets) from gaboon ply – it will knock about 1/4 of the weight off – good for carrying and reducing damage.

This Jarcat by Australian Ross Turner, a quite substantial boat uses 4mm (3/16″) ply with 2oz glass, showing that the recommendation for heavier glass is excessive for canoes and kayaks. The Jarcat sleeps four, sails fine and can motor at 10 knots with ease.

Ross Turner Jarcat only uses 2oz glass. Why do kayaks use more?

Jarcat in construction above – makes a canoe look puny, until you look carefully at the weight of the ply. this is a very sophisticated structure

You can always damage something by hitting it hard enough, but if the light glass will do for most of the pressures you will be putting on it.

I don’t know if it will help with the snakes though.

I would not do the whole outside of the Eureka.  You can eliminate the glass tape on the outside of the boat if you cover the bottom panel, the two bilge panels and go one inch onto the topside panels with the 2oz or lighter cloth.

This serves the same function as the external glass tape.

When sanding this light glass the sandpaper has to be kept very flat on the panels using a block or sander – don’t go around the corner to the next panel – that corner chine needs to be done separately – lightly hand sand (no sanding block) the around chines with worn out sandpaper (220 grit or finer) to get rid of the shine after epoxying. Watch carefully and as soon as the shine is gone … it’s done.

I have put a link at the top of the page to show how simple repairs can be.

repairing plywood boats. Hole in canoe, dinghy or yacht

Best wishes
Michael

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