Workboat restoration

[Captzig]

Hello all, longtime reader, first time poster.....
I live on the Chesapeake Bay and have a Bay Built boat, a 34 foot Carman to be exact. I have read everything I can possibly read but on here but most posts refer to perfect "mirror" hulls. I am restoring a workboat looks dont matter....I am replacing part of my floor and glassing the plywood over. I have considered using WEST System and cloth for this task. I then intend on cleaning and sanding the rest of all the entire topside glass, then rolling on new gel coat. My questions are.....
1) what type of plywood for the floor?
1a) Do you agree with West Sytem over cloth on the plywood?
2) What type of gelcoat to be rolled on(dont care about eggshell or looks)
3)Will 1 coat of gelcoat do the trick?

Thank you much for any info you guys can help me with. Captzig

[alan white]

I don't know about gelcoat. On a workboat, I guess I'd use pressure-treated plywood---- 3/4"-----but whatever ply you use, I'd put a heavy mat, not cloth, over it. Mat is cheaper and far thicker. Better to resist heavy usage. The West system epoxy is the only stuff I've used, but it seems to wet out nicely and hold up well.
The PT "deck" plywood is much cheaper than marine grade, though it has internal voids. This would be a bigger problem if no epoxy/mat covered it, but so long as you also seal the ply edges completely, you'll keep the sea out.
Otherwise, Doug fir marine ply is probably the ideal choice, but what's it selling for these days, and how much to ship to your location?

A.

[longliner45]

common mistake made on work boats ,like the mack truck (throw another ton on her shes a mack) is 3/4 ply decks ,if I could get away with 3/8 I would ..you got to think about your knees and ankles,,a little give in the deck dont hurt,especially if your gonna be on it a lott,,,I would go with 1/2 ,longliner

[alan white]

I had assumed we were talking about floor (sole) work areas. Using 3/8" or 1/2" on decks would be about right. Also, crowning makes for greater stiffness, something found on decks, cabin roofs, etc., but not too much on floor areas.
Frame spacing determines a lot too. Outer ply grain orientation should always be at right angles to frames, any case. I believe 1/2" ply (or 1/2" anything) deflects about twice as much as 3/4". They make rubber cushion mats for workboats, so there's some comfort. Yet the work area floor should stand a heavy winch or an anchor dropping onto it without structural damage.

A.

[gwboats]

I hope I'm not going to upset other subscribers, but I believe that soles (floors) in workboats should be as solid and firm as possible (within acceptable weight considerations). A solid floor gives a lot more confidence to the crew and absords the shock loads of heavy plant.

3/4" ply sounds good to me and a I would recommend using glass cloth with epoxy resin. Remember that plywood is made in a hot press and the surfaces fine sanded leaving quite an impervious outer 'skin'. Always abrade the surface and prime with neat resin before bonding on a 4 oz. glass cloth. A final coat of resin and silver sand will give a robust and non-slip surface able to withstand workboots (no soft soled yachty shoes here!).

For the topsides I would steer clear of gelcoats which are really a specialised product for use against a mould face. Abrade the topsides back to a sound surface, degrease and fill any damage with epoxy/silica mix. Hand roll on a good make of yacht paint and I think you will get good protection and a reasonable finish.

Good luck with the restoration.

[Captzig]

Thanks guys for the info. I have been kicking the idea of using epoxy topside paint (primer) instead of the gelcoat. My question is will it hold up on a workboat? I am guessing that once I go paint I can never go back without removing it all. Will the primer alone last? I am not looking for a shiny surface so I thought the dull white of the primer would be just right. Thanks again for the insight.

[longliner45]

are you going to be putting fish on deck? if yes ,,a smooth gellcoat is good ,,does little damage to your fish ,,and once every 2 or 3 yrs repaint ,, back to deck thickness ,,,its your knees and ankles,remember you will be out in all weather,,the less miserable you are.. the better off ,good luck longliner

[alan white]

Primer may discolor (becoming yellow) and pick up dirt and such, not to mention they are not formulated to resist UV. Petit makes a semigloss white one part urethane paint that is easily mistaken for gelcoat if properly applied. I've used it and it is a superb product. You could also use a two part, but it's harder to touch up, more expensive, and the fumes are dangerous to breathe.
Remember--- the shinier and whiter a surface is, the better the protection.
I don't know if a primer is really necessary on a really good surface but all older glass hulls are usually pitted and original release wax and maintainence wax is still in the old gelcoat, so DON'T sand before scrubbing the old surface first with acetone (gloves and eyes protected). The sanding might otherwise drive wax into the surface, which will cause paint adhesion problems.
I've had good luck with West Sytem microlight/ epoxy where scratches and gouges, nicks and so forth need to be filled.
A heavy bodied primer will fill the lesser scratches.

A.