Buoyancy is “the ability to float or tendency to float in water”.
To calculate buoyancy you have to calculate the weight of the displaced water and compare to the weight of the object. Weight is the force of gravity on an object’s mass so the unit of measure is Newtons (N). The gravity on earth is 10 Newtons. For examples, if you push a beach ball into the water it will come out very fast because the density of a beach ball is less than the density of the water (the density of the water is 1g/ml) so it will float. But if you a brick into the water it will sink very fast because the density of the brick is more than the density of the water. In conclusion,
In my boat i used a “round roof” and I hollowed it out so it could float then i put a keel so it would be stable. In my boat i made everything symmetric and i put a keel for the stability. A strong point about my boat is that it floats but a weak point is the stability so i should improve that.