Just a quick post about what is happening today in the world of SWW Yacht Design! It’s all fun and exciting stuff as we churn through engineering data and calculations to determine the structure needed to keep the yachts’ ballast bulb in place. 
The quick screen shot allows you to see what we have decided to do for construction detail. It’s a reasonably low-tech solution for a high teck piece of equipment. To hang a 2800 lb lead bulb at 6 ft. – 9 in. below the boat, we have decided to stick with a fairly conservative structure of type A36 mild steel plate. All pieces in the fin structure will be water jet cut out of 1/4 in. thick plate, the upprmost flange of 3/4 in. thick plate. These skins will be carefully shaped and fit to the internal “web” structural framework and welded into place.
The fabrication will incorporate the eight 7/8 in. diameter steel bolts tapped and welded into the flange. At the business end of the fin, the cast lead bulb will mate up to a female recess and mortise that fits the fin and “pin” plate, thru which two 3/4 in. steel pins will be installed to fix the bulb in place.