Monday, November 9, 2009

Stern Deck Beams

I've spent a couple of weeks filling, taping and sanding the inside plank seams. I also used fiberglass tape to tab in all of the plywood bulkheads. Now it's time to work on the decks at the stern and bow. They are about the same, being a double ender, but after doing the stern deck beams I decided to do the bow differently. More about that later.

I installed the main deck beam when I assembled the stem and number 10 and 12 frames together back when I was building the skeleton (see Building Ravn's Backbone in September's posts). The deck beam connected the top part of the two frames and the stem and made them stable enough that they stayed in alignment while I put them on the building form.

I should mention that the watertight compartments in the bow and stern are not part of the original Valgerda plans, although at least one builder in Australia added them to the boat he built from Atkin's original plan. They are, however, a feature in the Selway-Fisher Kari 2 plans.

I wanted the bow and stern compartments for two reasons: the reserve flotation should Ravn ever become swamped and dry storage for gear. I also think it will help keep the boat neat and shipshape, which enhances safety at sea.

The deck beams are made out of some old-growth douglas fir that I've had for years. A friend gave it to me when I was patching the fir floors in my 100-year-old home. It is tight, light and stiff -- just what you want for a deck beam. When you cut the wood it has a dusty, pitchy smell that is very different from the smell you get cutting into, say, a douglas fir 2-by-4 from the lumber yard.

I'm going to use 6mm plywood covered with 6-ounce fiberglass cloth for the deck. I would be a little more comfortable using 9mm plywood, but that would mean another trip to Portland and another $90. I have a full sheet of 6mm left over from planking so I'll use that. The thinner plywood means I need to put in additional deck beams so the deck won't flex too much.

I suppose I could write several posts on things I would do differently if I built the boat over. Not that I'm unhappy with how the boat is going together or the work I've done, but I feel a couple things could be improved upon. One thing I would do is put a deck hatch in the middle of the stern deck between frame's 10 and 12. That would be the best access to the space and it would be fairly easy to secure and keep watertight. It would also be fun to build and look cool. For now I'm going with a tight flat deck with limited access through the stern seat bulkhead hatch.

The miter joints into the main deck beam were easy to cut with my old Jackson backsaw and a chisel. Where the deck beams meet the side of the boat I simply scribed them with a compass and took them to the bandsaw. The miter joint into the main deck beam retained much of the meat of the main deck beam and did not weaken it substantially. When I was gluing the whole thing together I decided at the last minute to epoxy a rectangular piece of plywood scrap under both joints just in case. I'm kind of a belt and suspenders guy sometimes. It ruins the elegance of the joints, but no one will ever see them anyway.

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