Pontoon (boat) Pontoon (boat) A pontoon boat is a flattish boat that relies on pontoons to float. These pontoons (also called "tubes") contain a lot of reserve buoyancy and allow designers to create massive deck plans fitted with all sorts of accommodations, such as expansive lounge areas, stand-up bars, and sun pads. Better tube design has also allowed builders to put ever-increasing amounts of horsepower on the stern. Pontoon boat drafts may be as shallow as eight inches, which reduces risk of running aground and underwater damage. The pontoon effect is when a large force applied to the side capsizes a pontoon
Pontoon effect a trimaran with narrow-beam floats will simply submerge the lee float, exposing only the weather wing and that with a lesser moment. In practical sea situations the windage effect is greater than the buoyancy effect and so cruising trimarans with highly buoyant floats are more, not less, likely to capsize than those with less buoyant floats. A trimaran is best stabilised not by adding buoyancy on the lee float but adding weight to the weather float. This is the basis of the "cool-tubes" stability system invented by Tristan Jones and L. Surtees. A large-diameter pipe closed at the aft end