Our boat had a catamaran bottom. We did this because we wanted the least amount of styrofoam possible to be touching the water. We had the two pieces connected with popsicle sticks that also held the sail. The sail was originally higher but it tipped over.  Then we decided to lower the sail and move it farther back. Then we put some tinfoil around the mast and moved the mast all the way back so out boat wouldn’t nosedive into the water. Now our boat doesn’t nosedive.