Current Pole
Current Pole : A pole used in observing the velocity of the current. The pole formerly used by the Coast and Geodetic Survey was about 3 inches in diameter and 15 feet long, and was weighted at one end to float upright with the top about 1 foot out of water. Shorter poles were used when necessary for shallow water. In use, the pole was attached to the current line but separated from the graduated portion by an ungraded section of approximately 100 feet, known as the stray line. As the pole was carried out from an observing vessel by the current, the amount of line passing from the vessel during a specific time interval indicated the speed of the current. The set was obtained from a relative bearing from the vessel to the pole. The bearing was then related to the ship's compass and converted to true. See: Pelorus
No records Found