Buoyancy is a upward that is equal to weight of the fluid volume displacement.We can calculating by dividing volume by mass. I made my boat with three halls so that the buoyancy will be bigger. Stability is the ability of an object to not fall.I made my boat with 3 pontoons so that it will take more space in the water and won't fall over.
One strength of my boat was that my boat has enough stability that it can carry 4 coins but one of the weakness boat is when we start making turbulence the water starts to go in the front of the boat, because the coins are making the boat lean forward and because of that the water has a easier way to go in. One thing that I could do next time is put more weight in the back or perhaps put more space for the coins.