Plans built plywood hull - durability question

[metriccrescentwrench]

I'm thinking about building one of the Glen-L designs which will be a plywood hull with fiberglass laminated over the plywood. While I don't forsee any issues with the build one question is gnawing at me - how well do these hulls handle all the scrapes etc. that are bound to happen? I have visions of unnoticed damage leading to a rotted hull - is that unjustified?

thanks

 

[andgott]

Re: Plans built plywood hull - durability question

They are pretty tough- But you do have to maintain them! If the outer layer of fiberglass is 'compromised', by a scratch, scrape, or whatever, you'll want to fix it to keep water out of the plywood. If left alone, water will get in, and it will eventually rot.

But- Even if you DID have an area that rotted out because it got a hole that you didn't notice and left for a long time, it's not like the whole boat is ruined. You can cut that part of the hull out, and replace it, and it'll be as good as new.

There are THOUSANDS of boats built like this out there- and many of them are quite old... I know of a couple of Glen-L designed boats that are well over 50 and still going strong. Build it right, and it'll last. Glen-L has a strong following on the web, look it up- there are TONS of resources out there... Owners associations, clubs, etc.

 

[JimS123]

Re: Plans built plywood hull - durability question

I built one in the 1960's and it lasted for 10 years with no issues. It was a trailerboat, though, so it was not kept in the water. I hadly ever put scratches in it, and when I did I merely touched up the scratch with the same paint it was painted with.

All boats have some flexibility to them, and a plywood hull probably flexes more than most. I would NEVER, repeat NEVER laminate fiberglass on top of the wood hull. Any little delamination and water will get in and then you'll know what rotten wood looks like.

Back in the day it was common to do that. You'll get different opinions even now, and I'm sure somebody will come on here and flame me for saying it. Before I built mine I did considerable research on the subject and investigated other boats that were glassed. What I saw and what the experts told me convinced me not to.

 

[Cadwelder]

Re: Plans built plywood hull - durability question

My Dad built two Glen L boats years and years ago (one for him and one for my uncle). They were just small fishing boats, 25 HP Max rating, but we used the hell out it for well over 20 years and was still in good shape when he sold it (it was always garage kept) He didn't glass anything except for a 6" strip down the keel. It was just for a little extra protection in running up on the bank and the such. But the rest of the boat was just good marine grade enamel and we never had problem with it. Not sure how long Glen L has been around but I know for at least 50 years.

 

[metriccrescentwrench]

Re: Plans built plywood hull - durability question

All boats have some flexibility to them, and a plywood hull probably flexes more than most. I would NEVER, repeat NEVER laminate fiberglass on top of the wood hull.

Well, for one thing Glen-L spells out that this design is to be laminated with fiberglass, so I'd guess it plays a structural role. As for flexibility, I'll be using epoxy resin which is far more flexible and less brittle than polyester.

 

[sasto]

Re: Plans built plywood hull - durability question

I would go with it metric. I've seen some big boats made with plywood and epoxy. Big sportfish. Take a look at some of the battlewaggons that came out of Outer Banks, NC. that are still around and fishing daily. Glen-L's have been around my neighborhood for many years. Makes a good stiff boat to enjoy.

 

[oops!]

Re: Plans built plywood hull - durability question

metric.....there are several guys here that have built them........pm erik green.......he is really up on tech data and is building a woodie in his garage.

remember.......woodies are what marine plywood is for.

 

[robert graham]

Re: Plans built plywood hull - durability question

For years back in the 1950's my dad and I had a 16' Halsey plywood fishing boat, used paint on the outside(green on bottom and white on sides), and clear varnish/polyurethane on the inside, usually additional coats every year or so, always looked good and held up great. That natural wood just seemed to glow under the mutiple coats of varnish! Nothing prettier than a wooden boat!...

 

[JimS123]

Re: Plans built plywood hull - durability question

Well, for one thing Glen-L spells out that this design is to be laminated with fiberglass, so I'd guess it plays a structural role. As for flexibility, I'll be using epoxy resin which is far more flexible and less brittle than polyester.

If its stitch and glue, then you're right glassing is necessary. Not for structural purposes, but because the boat will leak at the seams without it. Also true about epoxy. Back in my day everybody used polysester becasuse thats what FG boats were built from so that was the accepted practice. And that's probably where it got its bad rep.

You better be prepared to epoxy the whole inside of the hull as well, because you will need to keep moiture penetration out of the wood at all cost. It won't breathe now, so rot will be inevitable in time if the wood gets wet. Plus, no matter how good your epoxy bond is, expansion and contraction of the wood due to wetting and drying isn't good.

But to your original question - just keep some resin on hand and repair scrapes quickly (after the boat dries) and you'l be OK.