Hull Terminology

Click on the thumbnail for a pictorial view of boat nomenclature.  Although this depicts a deep vee hull the terminology is generic to many hull types.

Beam: The width of the boat at its widest point, typically at the transom for planning hulls.

Bow: Front of the boat.

Chine: The line of intersection of the bottom with the side of a vee or flat bottomed vessel.

Deadrise: Degrees of V-shape hull angle measured at the transom of planing powerboats.

Deck: A deck in a ship corresponds to a floor in a building. It is the plating, planking, or covering above the inner bottom forming a floor.

Freeboard: The vertical distance from the waterline to the top of the deck at side.

Hatch: An opening in a deck through which cargo may be handled, machinery or boilers installed or removed, and access obtained to the decks and holds below. For R/C's this is how we access, servos, fuel and motor.

Keel: The backbone at the very bottom of the hull to which frames are attached.

Ride pad:  Ride pads are used to ensure that you get a clean edge to spill water off the ride areas to reduce drag and increase speed. They are an easy way to get a clean sharp edge.
 

Sheer: The longitudinal curve of a vessel's rails, decks, etc. the usual reference being to the ship's side.

Strake: Flat riding surfaces that run the length of the hull. Typically there are two outer strakes and an inner pair. Mainly found in Deep-vee type hulls they may also be found on some cats. The strake provides a small planing surface, the outer pair for low speed planing and the inner pair for higher speed. 

Stern: The after end of a vessel; the farthest distant part from the bow.

Transom: The board forming the stern of a square-ended row boat or small yacht.

Sponson Terminology

Click on the thumbnail for a pictorial view of the following sponson nomenclature

Dihedral: The designed angle between the planing surface of the sponson and the surface of the water, measured laterally inside to outside; a negative angle is called anhedral

Chine: The inclined side of hull or sponson.  The non-tripping chine-called the "non-trip"-comes into play mainly in rough water. When a hydro takes a fast turn, it rides the chine.

Crown: The top portion of the sponson, normally has curve so it can be more stable in a cross wind.  When air hits a non-trip chine without a crowned deck the boat is more apt to blow over.  The crown helps generate some downward force in a cross with to counteract the lift force of the non-trip chine.