One of the factors used to determine the speed potential of a displacement boat. The longer, the greater the speed potential. The overall length is irrelevant; overhangs fore and aft do not increase hull speed potential.

Related Terms

COLD CRANKING SIMULATOR

An intermediate shear rate viscometer that predicts the ability of an oil to permit a satisfactory cranking speed to be developed in a cold engine. (CCS)

GROWLER

A piece of ice smaller than a BERGY BIT or FLOEBERG, often transparent but appearing green or almost black in color. It extends less than 1 meter above the sea surface and its length is less than 20 feet (6 meters). A growler is large enough to be a hazard to shipping but small enough that it may escape visual or radar detection.

GROUND LOG

A device for determining the course and speed over the ground in shallow water consisting of a lead or weight attached to a line. The lead is thrown overboard and allowed to rest on the bottom. The course over ground is indicated by the direction the line tends and the speed by the amount of line paid out in a unit of time.

HEAVE

The oscillatory vertical rise and fall, due to the entire hull being lifted by the force of the sea. Also called HEAVING

SEA CHEST

An opening for supplying seawater to condensers, pumps, etc. located in the hull below the waterline and having means for the attachment of the associated piping

BROOKFIELD VISCOSITY

Apparent viscosity in cP determined by Brookfield viscometer, which measures the torque required to rotate a spindle at constant speed in oil of a given temperature. Basis for ASTM Method D 2983; used for measuring low temperature viscosity of lubricants.

ATOMIC ABSORPTION SPECTROSCOPY

Measures the radiation absorbed by chemically unbound atoms by analyzing the transmitted energy relative to the incident energy at each frequency. The procedure consists of diluting the fluid sample with methyl isobutyl ketone (MIBK) and directly aspirating the solution. The actual process of atomization involves reducing the solution to a fine spray, dissolving it, and finally vaporizing it with a flame. The vaporization of the metal particles depends upon their time in the flame, the flame temperature, and the composition of the flame gas. The spectrum occurs because atoms in the vapor state can absorb radiation at certain well-defined characteristic wave lengths. The wave length bands absorbed are very narrow and differ for each element. In addition, the absorption of radiant energy by electronic transitions from ground to excited state is essentially and absolute measure of the number of atoms in the flame and is, therefore, the concentration of the element in a sample.

ANGSTROM UNITS

A unit of wave length, equal in length to one ten billionth.

SHELL PLATING

The plates forming the outer side and bottom skin of the hull

TRIMARAN

A triple hulled vessel

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