Inside jobs.

The outside corners were trimmed in so that they did not form a sharp corner. Rather, I made radiused insert pieces for the corners. First,  a flat pattern was developed, then this was hammer into a round groove on a sage block, using a 3/4” steel bar as a top fuller. Then the pointy end was compound-curved in the small concavity on the swage block face with a small ball peen. Although the aluminum gets marred during this process, it’s easy to repair with a flap disc on the grinder.

Working in metric units is so much easier than inch fractions, once you get accustomed to thinking that way.

Dorade Boxes

Olin Stephens came up with the idea for the cowl vent atop a baffled box for his yacht Dorade back in 1931, one of many innovations on this classic wooden boat. http://www.sparkmanstephens.info/doc/40629a9KBM30p3th6KmXjv9HWbytVBoS.pdf

The idea is that air( and water) can enter the cowl , but the baffle and tube arrangement allow only the air to flow into the cabin below. The water drains away through scuppers in the lower edge of the box. Our yachts will have 6 Dorade vents: main cabin, single forward, head, galley and 2 smaller, shorter ones in the pilothouse roof. Each will have a fully sealing mushroom vent on the down pipe. Vetus is supplying the stainless steel cowls and vents. I designed a rounded box for the cowl to sit on: easy to fabricate, and the round corners will not snag or chafe any lines dragging by them. In order to be able to access the mushroom vent, I decided to bolt the entire assembly to the deck, rather than weld. A good seal around the bottom of the box is not necessary, as the water is meant to drain away.

We rolled the 5mm aluminum into cylinders, then cut them in half to form the ends of the boxes.  The joints were TIG welded together and the outside welds sanded flush.

The lids were plasma cut, along with the hole for the cowl vent. The flanges for the mushroom vent on the down tubes were bent from 5 x 20 mm flat stock and welded to the rim.

The overall aim right now is to get all of the major welding done on the hull areas that will be insulated inside, meaning between the watertight bulkheads. The list is long, but growing shorter:

attach hatch landings and dorades; chainplates; stanchion bases; grabrails; padeye and threaded insert attachment points on deck;

ports in hull; windows in pilothouse; traveller brackets; and plenty else, I’m sure.