Fiberglass over Wood plank Hull

[cygnus]

I need expert opinions on Fiberglassing over wood plank hull. I know the boat very well, no rot, 8 planks replaced recently, she was in a non heated shed for for 5 years. Built in 1936, always freshwater boat, as a young boy we owned her. Sold the boat to a couple [ 35 yrs. ago] who maintained her meticulously until present. He lost some of his eye site so can`t sail anymore. Boat is 25`x 9 beam 3` draft. Sloop with a jib boom. I want to bring her down to Fl but having a wood boat down here is asking for trouble I heard. If the Hull was glassed and matted over the properly is this a good idea? The inside is open meaning all the ribs are exposed [10 inch on centers]. I would leave these exposed for air circulation. I hate to see her just get cut up, she was too well maintained over the years plus a lot of history along with her. Thanks for all input on this subject.

[boatman61]

If the inside is open I would think sanding the interior back below the w/line to say a foot above so you have clean timber then epoxy with at least 3 coats and repeat on the exterior..
Glassing is only any good from new and on both sides.
Did this on a pitch pine on oak framed boat back in the 80's, the yard workers were gobsmacked when she did not take water on launch as is normal with planked boats till the timbers reswell.

[roverhi]

Plank on edge construction is almost always a disaster to fiberglass over. There is just too much movement of the planks for the fiberglass to wood bond to last. The plans swell and shrink from moisture and mover about with the stresses underway. The glass is a rigid fixed dimension sheathing and the bond soon breaks down with the wood. As soon as you get separation of the glass from the wood water gets in and the planks begin to rot. If your intent is to get another few years out of the boat have at it but the boat will soon be toast. Leave it as is with occasional maintenance, replanking, refastening that plank on edge boats take if you want it to live another 80 years.

You can glass cold molded, plywood and strip planked hulls because the wood is directionally stable.

[Pelican_38]

I agree with roverhi - it is almost always a disaster to glass over plank construction. The key word is "almost". The only cases I have seen this used to good effect is to get "just a few more years" out of a boat that's otherwise not worth repairing correctly.

Not only will you stop the planks from moving as designed, you will trap in fresh water which encourages rot and add weight the boat was probably not designed to handle.

[SV Windrush II]

I’m a wooden boat shipwright from a teenager, (I won’t say how old I am now haha) let’s just say I have built and restored enough wooden boats that all my friends and family think I’m crazy. First, the above advice is correct. If you want a wood carvel planked boat to last, do not fiberglass it. Just the humidity of the interior will make it rot out, not to mention any rain water intrusion, and it does not take as long as you would think.
Secondly, if she is sound already then recaulking and seaming it properly will make it last another 40 years if properly maintained.
I am currently cruising the pacific in a 52 year old mahogany on oak framed carvel planked boat that has proven to be stronger than most fiberglass yachts, but of course I maintain her daily.
Find some good pine tar to brush in all the seams before caulking, that will make the planks last a long time. The builders of my boat coated the inside of the keel and frames with pine tar when she was built and the wood is still rock hard. It’s only the plywood decks and cabin top that were fiberglassed that rotted out and therefore had to be replaced.

Put a little traditional care into your classic and she will outlive you

[Sand crab]

They say you want to staple the glass to the hull. This allows expansion of the hull planking without fracturing the glass.
fiberglass to old wooden boat

[Cheechako]

Originally Posted by cygnus

I need expert opinions on Fiberglassing over wood plank hull. I know the boat very well, no rot, 8 planks replaced recently, she was in a non heated shed for for 5 years. Built in 1936, always freshwater boat, as a young boy we owned her. Sold the boat to a couple [ 35 yrs. ago] who maintained her meticulously until present. He lost some of his eye site so can`t sail anymore. Boat is 25`x 9 beam 3` draft. Sloop with a jib boom. I want to bring her down to Fl but having a wood boat down here is asking for trouble I heard. If the Hull was glassed and matted over the properly is this a good idea? The inside is open meaning all the ribs are exposed [10 inch on centers]. I would leave these exposed for air circulation. I hate to see her just get cut up, she was too well maintained over the years plus a lot of history along with her. Thanks for all input on this subject.

Only as a last resort. If she's not rotten now she will be if you glass over it. Seen it many times. Moisture builds up inside and rot occurs quickly. I wonder if there would be a way to totally saturate the wood with epoxy first? Just laying up doesn't seem to do it.

[psk125]

This idea had proponents in the late 60's. Alan Vaitses wrote a book about it. We glassed over a Cape Cod Knockabout in our garage to keep it from leaking. The additional weight this added did not improve her sailing qualities, and the centerboard trunk still leaked anyway. We got rid of it. Many 'glassed over boats have succumbed to the problems outlined above. Unless a boat is built as a composite sandwich from the outset, with the requisite layers of resin (usually with epoxy now, because it adheres better to wood than polyester resin) and 'glass encapsulating the wood to keep it dry on both sides AND stuck together, things often start to go South soon after the "refit" is made. Sometimes it works. IIRC there was a pilot cutter that had her 100th birthday a while ago, while exploring Antarctica. Haven't heard much about her since then, however and can't recall the name. The Woodenboat forum would be a good place to get some informed answers to your question.