Would you buy it? Fibreglass over Mahogany

[Reflections101]

The boat is a one-off 42ft design built by a professional yard in 1981.

The hull is edge glued and nailed 1 inch mahogany. And here is the crux: The hull is fibreglassed over the mahogany (only on the outside). The boat has been in the water for the last 35 years, but had not done any significant cruising for a while. There are no obvious signs of problems.

Typically I get two types of comments:

"Run!!! Wouldn't touch it with a barge pole!"

"It has been professionally built like that from the start. If the survey does not show up any issues there is nothing wrong with such a construction."

PS: I searched the web about the issue but most pages refer to retrofit fibreglassing a wooden hull rather than as the original design.

PPS: And a final question. How would you rate a construction like this for strength/safety. Weaker than steel. But compared to GRP?

Thanks!

[boatman61]

There's a lot of ply designs/boats around the UK that were glassed externally and are still going strong 30/40/50yrs on..
If the timber was epoxy treated all over it should survive much much better than ply..

[Lepke]

If you like the boat, the price is right and you get a good detailed survey then compare the boat to your other choices in that price range. It might be worth paying a surveyor a little more to really get into the hull.
Wood alone can last a long time. I live on a 74 year old wood boat. My planking is 1.25". Wood commercial fishing boats of about 42 feet usually have 3/4 to 1" planking w/o fiberglass and usually survive heavy use for 50+ years. Some halibut schooners that are heavy built are still working at over 100 years.
I use to be a shipwright and have seen several combinations of wood and fiberglass. The trick is to keep the fiberglass maintained and bonded to the wood. Hopefully the builder used epoxy resin. Where screws and bolts go thru or into the wood it needs to be sealed in such a way that no water breaks thru the fiberglass. Depending on the thickness of the fiberglass hull, it could be much stronger than a hull of just fiberglass.

[Jim Cate]

FWIW:

Strip plank epoxy composite is a well documented construction method with many advantages. Some, as your example, are glassed on the outside only, while others, like ours, are glassed on both sides. Either way, when well done it is a very strong,, light and durable hull. Our is 26 years old, has done well over 100K miles and has no defects. last year we were T-boned at anchor by a 42 foot yacht doing around three knots. her bow roller punched two 1/4 x 3 inch holes through the outer glass and about 2/3 of the way through our Western Red Cedar planking. No hull distortion, the glass on the inside was not disturbed and the repair was simple, strong and undetectable when done.

There is certainly no reason to avoid this construction method... hope the survey goes well.

Jim

PS I note that you do not specify that the glass was epoxied. If per chance it was done with polyester, I'd not buy it!

[Reflections101]

Thank you all! Very helpful.

I am pleased to hear that it should not be a problem if the details are OK (thorough survey check, sealed screw holes, expoxy rather than polyester...).

Might be just nostalgia, but I like the idea of a boat built from wood rather than steel or plastic.

[minaret]

Yard built in '81, probably not epoxy, though it's certainly possible. More to the point, glass over teak is a huge no-no. Too oily.

[Reflections101]

Thanks minaret,

More to the point, glass over teak is a huge no-no. Too oily.

Sorry, it's actually mahogany, not teak. I noticed just after posting it, but can't figure out how to change the thread title.

Would mahogany make any difference or is it also too oily?

[Reefmagnet]

Originally Posted by minaret

Yard built in '81, probably not epoxy, though it's certainly possible. More to the point, glass over teak is a huge no-no. Too oily.

The title is confusing. The OP says it's mahogany in the body of his post.

[Wotname]

Was the fibreglass done an initial construction or added later?
Do you know who the builder was or their reputation?

[Cheechako]

Unsure if you are saying it was glassed when new??
If it was built without fiberglass originally..? Must have had issues that made it non repairable. There should be no reason to coat a strip/glue/nailed hull. They were great boats. So I would be very careful about investing too much in it.
I'm assuming it isn't just a composite strip epoxy type build, but rather edge glued and nailed type.
Could be a great boat, but watch value, insure-ability etc.

[Reflections101]

The fibreglass was done during initial construction by the boat yard. It is part of the original design.

As far as I know the yard has a good reputation. They had designed and built a series of quite successful 30' and 38' racing yachts, but when the original owner/designer died in 2008 the yard stopped.

I actually met the son of the original designer/builder and asked him about the boat. He says that the mahogany/glass composite is perfectly fine, but of course he would say that...

[Delancey]

As mentioned wood epoxy composite construction in it's myriad forms (strip plank, cold molded, plywood) can be an excellent boatbuilding technique.

Wood is a great boatbuilding material with many fine qualities and is also a renewable resource. After all, wood really does grow on trees as they say.

Wood epoxy composite construction techniques maximize the structural potential of wood while ameliorating it's inherent weaknesses and is especially well suited to plantation-grown non-old growth stock.

Not mentioned so far is that many fine plank-on-frame boats were killed by well intending individuals who skinned them with fiberglass. I have installed on my boat pairs of halyard and secondary winches salvaged from a once beautiful Herreshoff which suffered this fate and has since been acrimoniously resigned to a dumpster.

Without more information I think your task lies in determining which of the two types of build the boat you are considering is made of.

One red flag that stands out to me from your description, a mention on the strip plank thickness being one inch.

The Gougeon brothers, who pretty much wrote the book (orignally published in 1979 with numerous revisions) on wood epoxy composite construction, are specific in advising against attempting to epoxy encapsulate wood more than 3/8" thick. Encapsulation being a critical element of successful wood epoxy composite construction.

If you are really interested in this boat, I think it would behove you to familiarize yourself with the contents of book the Gougeon brothers wrote, for which I have include a link below. It is a wonderful treasury of information.

Cheers

http://www.westsystem.com/ss/assets/...k%20061205.pdf

[leftbrainstuff]

Originally Posted by Reflections101

The boat is a one-off 42ft design built by a professional yard in 1981.

The hull is edge glued and nailed 1 inch mahogany. And here is the crux: The hull is fibreglassed over the mahogany (only on the outside). The boat has been in the water for the last 35 years, but had not done any significant cruising for a while. There are no obvious signs of problems.

Typically I get two types of comments:

"Run!!! Wouldn't touch it with a barge pole!"

"It has been professionally built like that from the start. If the survey does not show up any issues there is nothing wrong with such a construction."

PS: I searched the web about the issue but most pages refer to retrofit fibreglassing a wooden hull rather than as the original design.

PPS: And a final question. How would you rate a construction like this for strength/safety. Weaker than steel. But compared to GRP?

Thanks!

All depends on the quality of the work. The issue lies with latent defects. They're latent because you typically cant find them before they become evident. What provenance do you have that the quality is what you think it is?

Personally I wouldn't touch it with a barge pole. I have 30 years (not continuous) of composites experience so I'm comfortable with grp rather than wood construction.

I like and have a well built tough cruising yacht, a Liberty 458. The hull is solid grp. The decks are grp top and bottom with epoxy ply and it's leak free after 31 years. The hull and deck joint is substantial.

There are still plenty of wooden vessels built pre grp that are still operational.

BTW its not possible to rate the construction without an inspection. It's a one off so we have no empirical or type data to go on.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[Wotname]

Originally Posted by Reflections101

The fibreglass was done during initial construction by the boat yard. It is part of the original design.

As far as I know the yard has a good reputation. They had designed and built a series of quite successful 30' and 38' racing yachts, but when the original owner/designer died in 2008 the yard stopped.

I actually met the son of the original designer/builder and asked him about the boat. He says that the mahogany/glass composite is perfectly fine, but of course he would say that...

Well IMO, it will be good. Epoxy / glass over edge glued planking is a perfectly good construction method as others have pointed out.

If the resin is still adhering to the timber after 35 years it is more likely to be epoxy that polyester but even in the worst case (polyester), it has stood the test of time. Mind you, I would remain cautious if it was polyester but if it proves to be epoxy, go for it.

[barnakiel]

I have seen a strip plank epoxied (since new) that was no good after only a couple of years in the tropics. However, the wood was not mahogany, it was a species of spruce.

I think that with the epoxy outside and (varnish?) on top of it you can just strip the hull to the epoxy and inspect the wood as the epoxy is translucent when wetted and mahogany is dark when rotten. Next inspect the wood on the inside - alike there will be very clear change of colour if the wood is wet or rotten.

If the wood is sound, the hull will be fine.

How strong is another matter. So much depends on hull shape, foils attachment technology, etc. It can be either strong or not. Same with other materials I guess.

I think a very very VERY personal thing. You will be sailing her, not others.

b.