Change in plans

Been scraping off the old epoxy and finally put new fillets in. But as I've been planning the mast and sail plan, I didn't like the designs that I came up with. The amas (side floats) would be plenty strong, but I don't know if the center sections would be very robust. Since I'd rather be sailing then swimming while pulling boat chunks behind me, I've come up with a new plan.

I will be building a Piccup Pram with a few modifications:

• The bow will be extended two feet into a tight V, making it 13 feet long (and no longer a pram)
• A bowsprit will be added for rigging a jib.
• 7.5 feet from stern will be a bolted bulkhead that separates the boat into two sections: 7.5' and 5.5' long
• When the front section is rotated 180, it can be placed completely inside the aft section; with lee boards nothing need be (and won't be) installed in the middle of the aft section that would interfere with this placement
• Instead of 1/4" plywood, the rear section of the boat will be made of glassed extruded-polystyrene foam, 1" thick; except the forward bulkhead which will be plywood to handle the point loads from the bolts. A 4x increase in thickness should result in 64x increase in stiffness (if they were the same material, but anyway...) allowing the aft section to do without bulkheads that would interfere with nesting.
• The bow section will still be 1/4" plywood: it won't have many or any point loads, so it needn't be strong in any particular point; it is much less wide than the aft section, so lighter construction can still be as stiff; and no one will sit there, there is plenty of room for reinforcing bulkheads.
• The width will need to be brought under 4 feet (from 4' 6").

Once built, I can easily double the size of the boat by inserting a new section in the middle. I could build a straight 8' section in the middle with amas on each side to maintain stability. Could even have a small cabin there! There would then be a second mast in this new section, probably larger and stayed, turning the boat into a schooner. But even if I didn't get this far, I'd still have a nice reliable boat based on a known working design.