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nathanielseattle
01-31-2010, 05:34 PM
Me and some friends are rebuilding a 42' ketch in Seattle.

Wondering what people think about laying a Port Offord cedar deck over a 3 1/4" x 1 1/4" CVG old growth fir tounge and groove decks. Originally it had canvas over it.

Our current thoughts are to lay the port offord down over it, our seccond thought is to lay some plywood down and glass it. We have a tight budget and currently already have the port offord.

Wondering what peoples thoughts on sealants are, could we lay roofing tar down underneath as a sealant?

One person was saying the tounge and groove may move around to much? The tounge and groove is nailed in with 3" galv. boat nails to 3" x 4" beams every every 12".

Any ideas and advice would be great.
Thanks
Nathaniel

paladin
01-31-2010, 06:48 PM
Go with the ply and fiberglass in epoxy over...otherwise you will spend 22 hours of every 24 trying to find/stop the leaks.

Nicholas Carey
01-31-2010, 08:20 PM
he tounge and groove is nailed in with 3" galv. boat nails to 3" x 4" beams every every 12".[just as an aside, what kind of 42 foot ketch has deckbeams sided 3 inches and molded 4 inches? That's some sturdy construction!]

I assume you're replacing the deck because of leaks, n'est-ce pas?

If so, do you know for sure that there aren't other, more insidious problem lurking underneath the T+G fir, caused by the deck leaks -- rotten deck beams and/or sheer clamp, for instance. Just sayin...

replacing the deck is rather labor-intensive, what with stripping off every bit o'hardware, etc. You might want to consider some exploratory surgery now, so as to avoid replacing the deck again in relatively short order.

If the fir subdeck needs to be removed to fix the problems caused by the leaks, then you might consider the Port Orford cedar as a replacement. But as Paladin said, you're likely going to be spending a lot of time chasing leaks. And given the value of good Port Orford cedar in these latter days, it might be more profitably put to a higher use.

Assuming that the deck structure is sound, then the simplest, cheapest solution would be just to re-canvas the deck. Done right, this will last a long time. It does need some maintenance (painting/cleaning) and it does require old-school yacht rules (no street shoes, period: dedicated deck shoes or bare feet only, please.

If you do recanvas, you should be aware that in a canvas on tongue and groove subdeck, the canvas is not lagged to the subdeck. This is to allow the subdeck to move as the vessel works whilst underway.

Failing recanvasing, I'd vote for dynel/epoxy over plywood. Either remove & replace the T+G fir with a structural plywood subdeck, or put a thin plywood skin on the T+G fir. Top the plywood with dynel and epoxy. Either will add significant structural rigidity to the deck structure -- oftimes helpful for an arthritic hull in her troisième âge. The dynel/epoxy can be given a modern look (fill the weave, mask out glossy waterways and paint the deck with paint with nonskid beads in it), or the look of an old-school canvas deck (don't fill the weave).

If you simply put Port Orford cedar on top of the fir, aside from the leaks issue that Palidon noted, you're going to add a significant amount of weight up high and affect the stability of the hull (not in a good way).

But, if you were going to put in a Port Orford cedar deck, then do it right. Strip off the T+G fir. Install a proper caulked Port Orford cedar deck (which also will add a lot of structural rigidity to the hull). This option, of course, requires maintenance, too. Holystoning (scotch-briting, these days) the deck. Not to mention tracking down the leaks. And regular washdowns in the summertime, to prevent it from drying out (au contraire, Hopalong, here in Seattle we get a lot of sun in the summertime. :p Mum's the word, though, we get enough furriners moving here as it is.)

Do the dynel/epoxy on plywood.

boattruck
02-01-2010, 11:29 PM
NS, I'm with Pal on this one, dry it really well, put down two lams of high quality plywood epoxy glued to each other, they will add a ton of strength and stiffness to an aging girl, we have used a polyurethane rubber coating for some decks with great results,(Universal Protective Coatings) as an alternitive to epoxy and glass, less exacting installation requirements...If someone 20 years back had put a properly sealed ply deck over the aging fir laid deck on my old ketch, as opposed to the thin overlay plank deck, I think my current work list might be shorter. Have fun, Cheers, BT