waterline length - The length of the boat at the waterline.
waterline - The line where the water comes to on the hull of a boat.
WATERLINE LENGTH-Significance: One of the factors used to determine the speed potential of a displacement boat. The longer, the greater the speed potential.
The ends are short to take advantage of waterline length and beam is carried well aft. The D/L is 165, and that is on the light side for a fully found cruiser of this size. The L/B is 3.45, which puts it right at textbook 'medium' beam.
A long counter increases the waterline length when the boat is heeled, so increasing hull speed.
The speed/length ratio (S/L ratio) is the ratio between the boat's maximum speed and the square root of her waterline length.
A quite recent one-design class has a length on deck of 40 feet 7 inches, with a waterline length of 25 feet. The sail area is 1103 feet, and the outside ballast weighs 6100 pounds.
With or without a bowsprit, if the mast is set well aft, abaft 40 percent of the waterline length, and the boat carries two or more headsails, she is a cutter. Confusion arises when a boat has her mast located forward but sets several headsails.
Cutter. One mast, stepped at a point about two-fifths of the waterline length from the bow.
Yawl. Two masts, a tall mainmast and a short mizzenmast stepped behind the rudder post.
PLANING SPEED - The point at which an accelerating hull rises onto the top of the water. To calculate a hull's planning speed, multiply the square root of the waterline length by 2.
PORT - The left side of a boat looking forward. A harbor.
Other lengths commonly referred to, though not in these Rules, include waterline length (measure between points where stem and stern enter the water) and length between perpendiculars (measured from the point the stem intersects the design waterline ...
beam and bength - The proportion a vessel's beam bears to her length varies according to her type. In sailing yachts it is found that for cruising a good proportion is about three and a-quarter to three and a half beams to waterline length.
But because of their design, displacement hulls are restricted in their speed to the square root of their waterline length times 1.34. Therefore, a 64 foot boat can realistically only expect a top end speed of a little over 10 knots.
Displacement hull boats have a maximum hull speed based on characteristics such as waterline length, draft, smoothness, etc. To overcome this limitation, planing hulls (speedboats) and hydrofoils rise out of the water at higher speeds.
Planing - To gain hydrodynamic lift, causing the boat to lift, rising slightly out of the water so that it is gliding over the water rather than plowing through it, reaching speeds in excess of those normally associated with its waterline length.
below deck hove to When a boat stops after being heaved to hull The main body of a boat consisting of the keel and frames, or ribs hull speed The theoretical maximum speed of the hull calculated by the square root of the waterline length ...
 See also: Boat, Waterline, Hull, Keel, Forward
|
