Neutral buoyancy diver maintains neutral buoyancy by continuous correction, usually by controlled breathing, as neutral buoyancy is an unstable condition for a compressible object in a liquid. The mathematician Archimedes discovered much of how buoyancy works more than 2000 years ago. In his research, Archimedes discovered that an object is buoyed up by a force equal to the weight of the water displaced by the object. In other words, an inflatable boat that displaces 100 pounds (45 kilograms) of water is buoyed up by that same weight of support. An object that floats in the water is known as being "positively" buoyant.
Buoyancy aid are several factors to consider which type to choose. These are designed with high maneuverability as a key feature, often at the expense of buoyancy. Minimalistic designs which tend to hug the body tightly and are well cut around the arms aim to allow the wearer complete freedom of motion (something important to both Slalom and Polo paddlers as well as playboaters). These vests may not be fully suitable for other purposes, such as whitewater paddling where additional buoyancy is required due to the higher flow of water. Canoe polo rules specify that the buoyancy aids must have protective buoyancy