Traveller Bulkhead

The Melges 30 was built without much in the way of stiffeners.  The original design was clever in its simplicity, and a lot of structure seemed to be derived from the companionway  and engine box plugging directly into the aft end of the keel trunk.  Rewinding the tape, one might recall that I chopped everything out of the boat, and with the longer doghouse, I've needed to take meaningful steps to make sure I have enough strength and structure.  

Without knees at the hull to deck joint, and only a center spine bulkhead, I couldn't seem to shake the idea that the cockpit pan wasn't really supported against parallelograming to leeward.  To combat that phenomenon, and to give the traveller something to pull against, I decided on making a stiff, transverse bulkhead, just aft of the new propane locker.  It should be noted that one of the original seeds for this concept was a similar strengthening element found on the Melges 30, Ballistic.

Here's a look at the part being vacuumed on the flat table at work.  I perforated the core with the CNC machine and a 1/16" drill bit, allowing air and excess resin an avenue to escape.  I put a lot of 45 degree fiber on this panel as I really want it to act as a lateral shear web.  This was the first time that I put peel ply on the bottom of the layup stack, as well as the top.  I did note that the bottom side of the panel seemed to hold a bit more resin with the peel ply down there, so it's not a magic bullet, but a reasonable tradeoff/shortcut.

Step one was modeling the bulkhead and copying the curves using the glue gun trick.

After roughing it out in door skin, I made myself a monofilm template and found a chunk of core off the scrap pile.

After the part was laid up, I brought it back to the garage and used the router table to recess the core in the corners where dings might be likely to happen.

I primed the freshly cut gutters, and used a squeeze bag to pack them with a mix of silica, balloons, and chopped fiber.

To finish the edge, I wet out some 200gsm plain weave between sheets of 4mil poly film, and sliced out some nice carbon tapes, which I doubled on each exposed edge.

Here's the part curing off with some peel ply ribbon to prepare the surface for the next steps.

Considering the build-up of carbon, 4lbs seems reasonable.

After leveling the boat, and tacking the bulkhead in a vertical position with the laser level, fillets were applied.  Finally two layers of DB90, one 5.5" wide, and one 4" wide were bagged down, top and bottom.