TOPIC: looking for Info on glass over wood hull method!

Oct 18 2016 01:03:30
Looking at possible purchase of 1961 Merrill 14 ft with outboard.
From what I am told Merrill Co. made boats in Portland, Oregon from 1958 to 1963. They are mahogany with fiberglass over hull. Very little out there on this former boat company...
My concern is this. I have read that this construction method is problem in that as boats age the Fiberglass can separate from "planked" and Plywood bottoms, due to many natural causes, wood natural moves, or decay starts under glass. Should I avoid looking at this type boat?
Or maybe remove glass?

What can you tell me about this construction method,and the issues that I may be getting into!

Thanks MIke Miller

Mike,
Glad you got it sorted out and started a thread about buying a Merrill.

Welcome to Fiberglassics, good luck w your project.

Post some pix of it.

Some of the most beautiful and graceful boats I have ever seen were made of wood. Add a layer of fiberglass to the outside and a lot of the maintenance requirements go away or are at least much less of an issue. However, they are not as durable or free of long term problems as say a molded fiberglass hull because the basic structure is wood. All of the things you mentioned can happen. But they are much less likely if the glass was applied properly and the boat was cared for to protect the wooden parts (long term) from the elements. If you like the boat, don't avoid the type just because it may need work IMHO.

Mike,
Welcome aboard, glad your here. Well my 2 cents is I'm not a fan of glass over wood for many of the reasons stated. The biggest issue is fi you don't get the glass on just right you run the risk of water getting behind/underneath it and the wood rots away unseen. I'm a pure glass bottom or pure wood bottom kind of guy.

Bob

Thanks

Thanks Jerry appreciate the feedback I am going to try and get a little more information,on how this was applied to bottom , but it makes me apprehensive not knowing if their is hidden damage.

Mike

Thanks Bob I agree Glass or wood.
I guess it would have lasted longer as a manufacturing method,other than just being more expensive if it was really better at protecting the hull.

MIke

A lot of companies did this back in that time frame. It's not bad, it is just not the best. They do occasionally separate.

So the way to go about this is to look at the keel first. See if it's been bruised by beaching, or punched a rock and had repairs. That is where a separation will start because the stresses are absorbed differently.

If that all looks good, look at the chines. See if they have started to separate there. Often there was a spray rail added to the chine and the glass was rolled around it. Over time the wood will swell and shrink slightly and pop the glass loose.

If those two areas look good, then take a soft rubber mallet (white if you can get one so less marring) and thump the glass from the bottom across the bottom all over. If it has separated, it will some loose like a snare drum. If it sounds tight, you are good to go

If any the places you check sound loose or bad, just lower the offer. Do you have a garage to work in at home? Will the ceiling joists carry the weight of a wood hull while working? It's not much, but some garages are not really strong enough ...

If you get it and you need to make a few repairs, just come back and we can assist after seeing pictures. It's not as bad as it might sound

This is a subject that is very controversial in the boat repair community. You will find people who swear by glass over wood and others who swear at it. I have done both and currently have two smll wood boats that are glassed over ply. My dad and I built a small sailboat back in the 60's and glassed it. What is left is junk and the wood has long since rotted away.

Usually new wood boats are never glassed. Boats that are glassed are done to either extend the life of an old boat that isn't really worth rebuilding but still has some life in it, and it is done on a lot of small boats as protection for the bottom against scrapes and scratches and damage from dragging the boat across the beach.

So the answer to your question is, if done right it can be good. If not it's a disaster waiting to happen.

The answers above are good advise. also look at http://newboatbuilders.com/docs/fiberglassoverwood.pdf

I'll wade in here as I've done a few glass on wood projects. The complication of the glass is it interferes with the drying process if wood gets wet. All that has been said is true. I'll just add a few thoughts.
Delamination is the kiss of death, water will wick in but will not really dry out, a rot recipe.
Also a planked boat is very different than a plywood boat. Plywood is way more dimensionally stable is a much better candidate. I would not glass a planked hull, too many flexing joints, the glass layer will crack along the joints as the abutting wood on each side moves differently when impacting waves and will break the glass fibers , but plywood can be done successfully with a few caveats... my opinion.
I would also only use epoxy resin as it is less permeable to water and it adheres much better to wood than polyester. I also think biaxial stitched mat is superior to woven 90 degree cloth. I generally do biaxial followed by cloth to give it a smoother surface to finish. fiberglast.com has sample packs of glass fabric materials to make the correct choice in material weight and glass orientation easy. Try and do continuos cloth or have generous overlaps, sometimes 6 inch tape on seams and corner details to start then move on to cloth to "connect" the taping. I use biax tape as it conforms better.
Pay close attention to your trailer so boat is well supported with no pressure points created with a missadjusted roller or bunk. This may lead to localized flexing and lead to delamination in that area.
Once wood gets wet debonding ensues due to wood swelling and shearing away at the bond line area, it may even be the fibers of the wood shear if adhesion is good, add a complication of freezing in colder climates which expands the now wet wood further. The process continues hidden fro view, it does take years.
Water collecting IN the boat due to reasons other than the obvious leaking is also bad as it soaks into joints and the wood will wick it in causing similar issues, it does not matter which side the wood gets wet from.
My take is this, workmanship and materials are key. Careful treatment of boat is key. Keeping after any water from rain or other fro sitting in the bilge areas is key. Trailer and launch care is key.
All this sounds discouraging, it shouldn't as I'm sure your restored queen will be handled like a gem. I give these same considerations of care and attention even to my glass boats.
My quote to any passer bye commenting on the collective extrodinary condition of our old boats is "Nothing ruins a boat faster than the sun and water" So care is really what matters as much as the quality of the resto.
I always have a quality full cover made for every resto to minimize water getting in and sun beating while not in use, it's worth the money after all the time and effort we put in. I have found several suppliers that have correct patterns for an incredible range of vintage boats and a correctly picked generic works OK too.
Picture of my glass over plywood up to the waterline Hiliner which is what factory did on these.
Good luck,
Randy

Fiber-glassing the bottom of a boat is generally only done as a patch job for a boat that needs a new bottom. Everything that 63G3 said above is true except that I would argue that there is never a good reason to fiberglass a bottom. A "good" job will simply allow the wood to rot slower.

I would flip it over, pull the bottom, fix or replace the framework and then replace the bottom using copious 3M 5200. If you have a planked bottom and don;t really care about originality, I'd go with high quality marine plywood...cheaper material, a LOT less labor much easier than re-planking. Either way you go, CPES both sides of everything. The new bottom will outlast the owner.

The only time you should consider fiber-glassing a wood bottom is on the boat of someone you hate.

I agree with Nautilus. I have a 1936 16' barrel back Chris Craft racer. It was owned by an employee of my father. He fiber glassed the bottom to the waterline back in 1970 and did a very nice job. The boat was put into storage in 1977 after it sunk at the dock due to a delamination issue. When I replaced the bottom, I was concerned on how I was ever going to remove all of the glass. A piece that was loose on the transom was starting to peel. I pulled on it and in less than 10 minutes I had all of the glass removed from the bottom. It had covered a multitude of sins!

I agree with Nautilus. I have a 1936 16' barrel back Chris Craft racer. It was owned by an employee of my father. He fiber glassed the bottom to the waterline back in 1970 and did a very nice job. The boat was put into storage in 1977 after it sunk at the dock due to a delamination issue. When I replaced the bottom, I was concerned on how I was ever going to remove all of the glass. A piece that was loose on the transom was starting to peel. I pulled on it and in less than 10 minutes I had all of the glass removed from the bottom. It had covered a multitude of sins!