: Hi everyone,

: Scarfing is well underway for our Yost SeaTour EXP 15s, and we're looking
: forward to the next steps. One quandry we're foreseeing, however, is that
: while there's certainly enough wood in our 4'x8' sheet of 1/2" okoumé
: for the frames and bow/stern plates of both boats, the coaming rings
: appear to be another story.

: The manual calls for three rather large rings of the 1/2" stuff, capped
: by a lip made of 1/4" ply. Since I don't want to buy an additional
: sheet of 1/4" okoumé, or use up a ton of the stuff I do have, the
: scheme I've in mind goes something like this: -Use 1/2"
: exterior-grade plywood for the first two coaming rings.

: -Instead of a third 1/2" ring and a 1/4" lip, simply cut the lip
: out of the 1/2" okoumé.

: -After they've been well sealed, wrap the edges of the ugly lower-grade
: plywood in some nice-looking bendy wood to preserve the "look".

: This plan would leave the coaming 1/4" lower and possibly slightly
: heavier than it would be according to the plans, but has the advantage of
: conserving our okoumé, and saving us money, while looking "just as
: good".

: So my question is, is this a foolish thing to be considering? How important
: is that extra quarter inch? Would a thicker coaming lip somehow be a
: problem? What about the non-marine aspect? I don't envision the coaming
: getting persistently soaked, but then again, I don't have enough
: experience to know what to expect.

: Thanks!

: -Jonathan and Amy

I have used non-marine plywood for the coamings on some Yost style SOF boats - successfully.

IIRC, the first 1/2" ring is the baseplate. The other two 1/2" rings are permanently bonded to each other, and the 1/4" lip, to allow the spray skirt and (optional) sea sock an inch of room to fit between the lip of the coaming and the hull. A single 1/2" ring won't leave a lot of room for the shock cord . . . but it is doable.

I suggest you buy an additional sheet - or half sheet - of 1/4" non-marine exterior plywood (the very best you can find), and use that for your coaming lips. If you can, you might try filling any voids in your non-marine ply with thickened epoxy.
1/4" marine ply will normally have more plys than non-marine, so there is a strength difference.

Personally, I wouldn't worry about wrapping any of the coaming with bendy wood, but that's an aesthetic choice. No one will see any of your coaming under a spray skirt or sea sock, in any case.