The new design

The design of the new, unnamed boat is very similar to Aerie’s: marine plywood, v-bottom, four strakes per side, 176 inches long. It has some important changes in the structure and sailing equipment, all born of experience:

1. It is built around a three piece backbone consisting of keel/skeg, keel/stem and centerboard trunk all joined together, with the keel made of two layers of 12mm (half inch) plywood. Instead of a keel batten, garboard cleats are glued and nailed to the keel and CB trunk. 
2. Another important modification is the design of the centerboard, whose pivot bolt is positioned on the keel under the hull, to prevent leaks through the pivot hole. The centerboard is wider and the CB trunk is almost completely enclosed, with a small corner opening for the line and blocks for raising and dropping the centerboard. This will prevent water from splashing into the boat. The centerboard will be weighted with lead, both so it can drop easily and for ballast below the waterline when lowered. The CB was designed in tandem with the sail for a balanced helm, using techniques learned from David Nichols' The Working Guide to Traditional Small-Boat Sails.
3. For simplicity, the boat will be a cat with a single sprit sail. This way there will be no halyards (the sail will be permanently laced to the mast), no boom and only three lines: a sheet clipped to the clew, a snotter for the sprit and a brailing line for dousing the sail in rough weather. Again, thanks to David Nichols for many ideas. This being a sea-going vessel (albeit in the Mediterranean and very close to land for beach hopping only), a small outboard and oars will be on hand for when the wind is too weak or too strong.
4. The fact that I am building a cat means that there is only one forward bulkhead, at 28 inches (711mm) aft of the stem of the boat. The mast partner will be secured to this bulkhead and the foredeck.
5. The new boat has a bit less freeboard. I found that Aerie had too much, especially for the purpose of fitting an outboard. An added bonus is that the long hull pieces (garboard & strakes) will fit on two pieces of plywood (scarfed together) per side.
6. There will be a bit less in the way of seating and no lockers (again for simplicity). Instead there will be four storage compartments with open access ports cut into the bench risers. In addition, there will be three buoyancy compartments (fore of the transom and under the foredeck and rowing thwart) filled with expanded polystyrene. I got tired of relying on watertight compartments for buoyancy: they never are fully watertight and are a pain to drain and dry after water gets into them. I will make sure that the compartments have drainage holes. 
7. There will be no floorboards, which proved to be an annoyance on Aerie. Instead I will reinforce the bottom with extra plywood strips and finish it with anti-slip grit.