Boat BasicsTransportation Engineering

Spring 2013Mr. Joel Bischoff

How does a boat float?Buoyancy

the tendency of a body to float or to rise when submerged in a fluid

the power of a fluid to exert an upward force on a body placed in it; also: the upward force exerted

Buoyancy vs. DisplacementDisplacement

the volume or weight of a fluid (as water) displaced by a floating body (as a ship) of equal weight

In short, buoyancy = the weight of displaced fluid

This also hold true for submerged objects

What are the parts of a boat?

What are the directions on a boat?

Hull Designs2 Different categories

Displacement designed to move through the water with a minimum of

propulsion. They will have a large underwater profile and will ride comfortably although slowly. Trawlers and large sailboats are displacement watercraft

Planing designed to actually rise up and ride on top of the water

when power is applied. They require considerably more horsepower to get the boat up but they can attain much higher speeds from the reduced friction of moving on top of the water rather than through the water

Hull DesignsFlat bottom

Very stable in calm waterFlat, broad bow makes a rough ride at higher

speeds, therefore they handle poorly the faster they go

Hull DesignsVee/ Deep Vee/ Modified Vee

The "V"-bottom boat is probably the most common hull design. Most manufacturers of boats built today use modifications of this design. This design offers a good ride in rough water as the pointed bow slices forward and the "V"-shaped bottom softens the up-and-down movement of the boat. The degree of the angle of the "V" is called "deadrise." As the "V" shape extends to the back of the boat, it usually flattens out until it all but disappears at the transom

Hull DesignsCatamaran

2 Hulls that are joined together by some type of structure or frame

Pontoon boata flat, raised deck supported with two outer

hulls (pontoons) that are usually constructed of aluminum