The definition of buoyancy the amount of water displaced and is the upward force on an object placed in water. Stability is how how stable something is if the boat is stable it wont sink. My boat is very stable. For extra stability I added hollowed pontoons and a keel to make sure I wont sink. The shape of the boat was like a tube that you would use to save someone or go down a waterside on so it was stable. I am not the happiest with how it turned out, but it did float.
The boat met the requirements of the challenge. it was very bouyant, as there was 0.25 n of force pushing upwards on the boat keeping it floating. However when coins were added the boat could only hold three coins in it, because more mass was added to the boat. The second requirement was stability. The boat was stable because the design of the boat had pontoons on it to keep it stable, because with pontoons made the surface area bigger so it would be more stable, and the keel that makes the boat more upright helps the boat be more steady when waves are being made.
If I could make the boat again I would make it bigger, I would add more pontoons to make it more steady by making them longer, and wider, and add a bigger Keel for stability so the boat wouldn't fall over even with coins being placed on it.