Carnal sin? Fiberglassing a wooden boat

[BMcF]

I'll just mention a technique that is used here where I live to glass over wood boats in use by local '6-pack' charter captains. These boats are in the 40-50' size range and are 'bay built' box-stern dory style boats (pretty heavy pine planking with oak frames and keel) that were originally built and used for oystering and crabbing. I should mention that the process these guys have come up with passes USCG inspection, for whatever that is worth. After one of them sank with loss of life about 15 years back, the inspection for the planked/nailed fishing boats became a bit much for the guys to deal with..so they came up (don't know how) with this fix.

After drying out the hull as much as possible, the entire exterior surface of the boat is coated with 3M 5200 to a depth of between 3/16"-1/4" using trowels. You can actually buy that stuff in 5-gallon buckets too. Then polyester glass is laid up over the cured 5200..a fairly thick layer but I'm not sure of the specs on that. Then the exterior is then hand faired with polyester fairing compound and a coat of Awgrip applied. Lot of labor involved..but they look like factory glass boats and have been holding up superbly well. I know that some of them are going over 10 years and counting after they were covered.

Maybe after thinking about the above, some of you would have an idea or two about why that process seems to work. I'm guessing it has a lot to do with having that 'fexible' but totally impermeable layer between the wood and the glass. Me, the only glassing over wood I ever did was to put a 1/4" layer of epoxy glass over the bottom of my '53 Chris Craft,,and it was about as dry as a boat could be when I did that, having been stored in a tight barn under cover for 20 years prior to me glassing the bottom.

[PAR]

This is often done to working class vessels. These old workhorses have spent their better days afloat and are on a quick down hill slide, when they undergo this treatment. They mold a new skin, which has sufficient thickness to become a new hull. The wooden structure still rots, but keeping up with seams and other under water hull leaks are mostly eliminated. If the sweet water can be kept out of the bilge and repairs kept up on the remaining wooden pieces, the process can add considerable life to a tired old girl.

It adds a bunch of weight to the vessel, but most that have this done can carry a hefty load. Ultimately the moisture will find a way into the well worn wooden pieces. It also rivals the cost of new bottom planks and frame repairs on a lot of these boats. This is why only well used up craft get the goo and snot treatment. If a boat has enough life in her, she'll receive new planks and frame repairs when necessary, rather then live on the hard for a few years, until someone smears her flanks with goo and hopes for a re-launching.

[old-boat-man]

It no doubt adds a bunch of weight to the vessel and is generally done to "dying boats". However I have done this more often than not over the years to good wooden boats and suprisingly most of them actually float higher on the water line than they did before glassing because the glass will obviously displace more water.However this wont help your fuel bill none.Although the old fishing boat I mentioned above as having a new hull built outside her old hull was an extreme job and added probably a good 4-6 tons to the boats original weight actually did better on fuel after its new structure was built,so go figure. Whatever you do and no matter if you use polyester resin or Epoxy be sure to always fasten it to the hull every six inches or so and you should have good luck.

[longliner45]

the reason they float higher is because the wood dose not get waterlogged,,thus less wieght,,,longliner

[Poida]

Longliner perhaps this should be on the brainteasing thread, but I go for the extra size of the hull decreasing the draft. I wish fibreglassing a hull did prevent the entry of water then I wouldn't be having to do the repairs I am doing now.
Poida

[longliner45]

poida ,,what about the wieght of the glass?,and surly it keeps most water out ,,maybe you should shut your hatches?if done properly ,,you should have no water coming in,,,,was your bottom nicked?longliner

[Poida]

Longliner it was done by a previous owner who also coated the inside of the hull.
I am currently removing the inside coating and replacing timber and/or filling as required. I don't believe fibreglass prevents water from entering as it is very brittle and will eventually crack and allow water in.

I'm having a break at the moment, better get back into it.

Poida

[longliner45]

yes water will eventually find its way in with fiberglass,,,,,,and gellcoat ,,Im in the process of putting 2 part epoxie on the outer skin,,,hope this does some good,as I will put in at lake erie,,,,good luck pioda ,,,,longliner

[Poida]

I was under the impression that you couldn't epoxy over fibreglass as the spirit based epoxy reacts with the fibreglass. But I'm probably wrong, again!

Poida

[longliner45]

im sure gonna look into it one moer time before I do anything ,,thanks poida