In sea, lake or river playgrounds people enjoy boats. Everyone that goes out in boats needs to be prepared and know what to do when the going gets rough, in particular how, when, where and why to keep their boat afloat.
Boats stay afloat when they are buoyant.
When a boat is lowered into the water it appears to lose weight and float. This is because the water pushes up against the hull. This is called buoyancy . When the boat floats freely in water the pressure the water exerts on the hull is equal to the weight of the boat and everything in it. This is called inbuilt buoyancy .