A Thick Glass Over Ply Hull?

I think I can hear you laughing right now in fact.... But, someone suggested I look at the proposition of laying a very thick layer of glass over my rotting ply hull on a 33ft hard chine cruiser, that is over 20 years old. on oregon frames. Now I haven't seen or heard of this before and I guess theres a good reason why.
Can anyone tell me that Good reason ?

Thank you. Neilium

 

I have to ask… what you hope to achieve by doing this?

If you are looking to make male mold for your boat there are easier and more cost effective ways to achieve a better result.
By doing this you would ultimately compromise the characteristics of the materials used.
My perceived concept behind hard-chine ply construction is that it is relatively cost effective in new build boats and can be maintained equally easily by cutting out damaged/rotten panels and replacing as, when, and where required. The level of fiberglass skill involved in hard-chine/flat paneled boats is not beyond any seafaring person and materials (marine grade ply) are available everywhere.
The advantage of 100% fiberglass construction is that you can design and build a sexy looking boat, with compound curves and no hard edges to cause drag. The fact is the vessel gains a lot of its strength out of these compound curves (I think this is the right name for them, you know the ones that curve in not two, but three directions/plains.) and to do away with them would compromise the strength of the fiberglass it self.
If you were to do this you would end up with a hard-chine fiberglass boat, which would weigh more, and have every surveyor rubbing their hands together. In the process you would have to cut out the rotten ply, and replace the frames and interior of the boat… The more I think about it the less feasible it is.
The hull is not the most expensive part of the boat. If a repair using the original construction method is, for some reason, not your first choice, and you like hard-chine, then I would suggest look at hard-chine aluminum construction going on in Oz, it is hard to compete with that sort of quality workmanship and the prices to lock up stage are very low.

Hope this has helped,

Dan

(P.S. I am not the most qualified person here to pass judgment on boat construction, but I do know what its like to ask post questions and get no response… don’t worry your not the only one with question that make ‘professionals’ shake their heads…)

 

re the crazy grp idea

Dear Dan,
Thanks for your quick reply. A friend suggested that idea as a way of dealing with the continueing saga of removing rot from this boat. Yes Iam one of those trusting souls... till now, that took a neighbour of ten years to his word. And am stuck with a sinking boat with rot everywhere and I think it will just be found wherever I look it's soft on the inside of the vertical sides of the hull right along the inside of the chine just above that stringer or whatever its called it holds water in there like a channel. theres even small crabs in my boat and seaweed. I'm about to slip it and leave it dry after pushing my hand through the rotten bits to let the air in.
I thought it was a crazy Idea but had to ask.
Thanks once again. Neil

 

Glassing an older wooden boat is generally not a good idea, for several reasons, none of which I need go into here. The bottom line is what YOU want from this craft. If you are looking for a few more seasons of use from a tired old hull then a light layer of glass will do the job, though, eventually will kill what remains of the wood. If you want to keep this boat, but don't want a bunch of bother, then put a "for Sale" sign on her and hope to get lucky with an understanding buyer. If you want to keep the boat and pass it on to your son, then the repairs must be made, which can include a well thought out light layering of glass on the hard spots (chine, keel, etc.) for abrasion resistance. A heavy layer of glass will be, in a word, "heavy" and your design may not be up to the task of toting around the extra weight and performing to reasonable expectations. There is no "cure in a can" unless you want a short life for her. In that case, then a light layer of glass is all that is necessary.

 

Junior The Page Wont Recognise My Login...

Thanks Par,
the messages are sinking in, looks like I'l be doing a lot of upside down ply replacement very shortly... not looking forward to it.
Cheers Neil

 

rotting 33

On a boat of that size in the condition described a good drying out is in order before any repair, quick fix or long term.Glass and resin will not stick to water saturated wood.A Cover-it shelter with the greenhouse tarp is an excellent lower-cost shelter to house the vessel in to dry it out.Proper support must be maintained during this process(two bys attached with screws to keep the hull in form before flipping over)Depending on your location repairs should not begin before hull is dried out(two months average in a greenhouse)After chemically removing the hull paint(or using a heat gun,please use proper breathing protection)down to the bare wood, follow standard epoxy application techniques outline in the West System book "Repairs to wooden boats"(Free where West System is sold)I wouldn't start with thick glass, but would gradually work my way up with 6oz cloth and unthickened resin.The previous post is correct, without extensive replacement of ply and frames you may enjoy 3 years at best.Then again, if you build the layers of glass correctly and use two part epoxy primers and barrier coats before painting you may enjoy more.Lot of work man.

 

However suggested that, probably read this
book:

http://www.amazon.com/exec/obidos/A...?dev-t=D1KQJBNTALRLQH&camp=2025&link_code=xm2


...which is probably worth reading if you are serious.



This method of fiberglassing a wood hull, referred to
as the "Vaitses Overlay," is specifically mentioned by
the U.S. Coast Guard as an accepatable method of
wood hull repair in NVIC 7-95.

It should be noted that the U.S. Coast Guard is not
necessarily the ultimate authority in wood hul repair,
although Alan Vaitses very well may be.

 

The USCG is not even close to understanding wooden craft repair or restoration. They are quite clueless as are most insurance companies. There isn't a boat restorer worth their salt that would recommend a heavy glass sheathing of ANY wooden boat of ANY construction method. 'Glassing a boat is a quick fix that WILL kill a wooden boat in a very few seasons. If you want a few seasons work from her then by all means, 'glass her up and watch her rot. Ask any professional fishermen whom wanted a little bit more from his old girl. They'll tell you it worked great, then went down hill quite quickly. The downward trend for the death of the crafts in question could have been forestalled with PROPER repairs and maintenance, but the cheap basterds went the easy way and killed the thing with the quick fix. Damn I hate to see good boats treated in such ill regard as to pay attention to fools with no credentials. I grew up on an island full of foolish fishermen like that, you don't have to if you don't want to . . .

 

"...fools with no credentials..."



I thought that the author of the book had
rather impresive credientials:


http://www.geoffdevine.com/vaitses.html


Although, having dealt with the Coast Guard
on inspected vessel matters and in commercial
towing, I do share most of your views as to their
qualifications.

Coming from a "work boat" background, where a
boat must pay her way, I am certainly envious of
those individuals who can lavish virtually unlimited
sums of money on "restoring" fine wooden craft.

And am almost equally envious of those individuals
who can make a living working on such works of art.

 

There's only one reason to glass over a hull with a thick layer, and that's to make another boat of the original. This is why the USCG recommends it and tired old work boats get a new lease on life, the craft is incased in a new hull of 'glass (until the old one rots and falls down inside it)

In the case of a working craft, it can make much cense, as it provides some years of service for a hull that has already or nearly so paid for it's self and new construction would be much more. In regard to the USCG, by their own admission, they don't want, like or would like to have on USA's waters, wooden vessels of any type. They site, sinking and safety issues, more common to the material then any other, plus the insurance companies pressure.

The simple fact is wooden construction is on the bottom of the list when it comes to neglect. A wood boat can not live with it for near as long as 'glass and other materials, and has a bad rap. The facts differ from the views of the USCG.

The average pleasure boat in this country gets 20 hours of use per year! The extreme vast majority of these are not wood. The average wooden pleasure boat in this country gets near 100 hours of use. This means the wooden boat owner is aboard his boat 3 1/3 times more often, where maintenance can and does get performed. The average wooden boat is in far better condition then boats of other materials, for this very reason.

I'm currently finishing up some rib repairs and bottom planks on a 25' - 40 year old Lyman lap strake hardtop cruiser. This boat is all original, looks like a million bucks and is a head turner at each pier she motors up to. This is her first full bottom plank replacement, the topside planks are as they were 40 years ago. The garboard seams wouldn't stay tight any more because of neglecting the bottom and bilge, so the new owner is biting the bullet and replacing the frames and planking from the waterline down. Had the previous owner, not let the bottom get away from him, this wouldn't be needed, but he was getting very old and didn't have the time or energy to play with his love any more.

I have a 45 year old Chris Craft of similar construction (27') that is all original, planks, running (but very tired 283) frames, transom, etc. It's had a good life, and been treated well, though she's showing her age, needs a new deck some day soon, engine could use freshing, but other wise a well cared for craft with much to offer, still running to 32 MPH on that weak old Chevy. She should run faster, but she's tired and I got a line on a 350, so . . .

I too come from a work boat background and am able to justify many short cuts and techniques the "pros" don't want to hear, but when the facts are in, 'glass on a wooden hull for more that abrasion resistance, is a waist of 'glass, unless you're trying to embalm the boat for a few more seasons of use, or get a USCG or insurance company certificate of some sort.

 

OK, I'm no carpenter, and I don't know about the effects of glassing over wood. and I've learned some stuff from this thread. very enlightening!

My history teacher in highschool once candidly said..."There is no such thing as a foolish question...only fools that ask them" HA!
OK, I was wondering about a "quick fix" for a rot or hole in a wooden hull. could a person cut out the rot, then form ALUMINUM sheeting over the hole and make a gasking from rubber and/or calking sealant? I'm not saying it would be a total cure, but it seems like it could be feasable to me.. but I don't know...thats why I'm asking.
THANKS!
Tim

 

I have to agree with you...the coast guard has no clue about wood boats where I'm from(new hampshire).I have seen several 40-50 foot wood boats that have been glassed over and have no doubts that they will get another 10 to 15 years out of them that they wouldn't have gotten otherwise.I have two layers of west system up over my prop and along the garboard and down the stern post on a 45 foot dragger that has been there for 4 years and looks like it was put on last week.

 

Quick fix for a hole

Is the hole less than 3 inches in diameter?Install a bronze petcock/with cap,along with liberal amounts of 5200.Larger?1/4 inch marine(or exterior glue)ply,unthickened epoxy to wet everything out(Bilge) followed by thickened epoxy(cabosil thickener)Then a 6 ounce fiberglass cloth patch with liberal amounts of epoxy,then grind,then smooth.Then a two-part epoxy primer.The a bottom paint from hell,Voila!