Sperry Division Designs Steering Gear Failure Alarm And Flash System
A system that rings an alarm and flashes a light in a ship's wheelhouse just seconds after a steering gear failure occurs has been designed by the Sperry Division of Sperry Rand Corporation.
Called the "Steering Failure Alarm," the system is intended to prevent groundings and collisions attributable to steering gear failure, an important cause of ship accidents.
The system will be installed on nine liquefied natural gas (LNG) carriers being built in the United States and France for El Paso LNG Company. In addition, a system has been ordered for a Chevron oil tanker.
The Steering Failure Alarm contains patented circuits which respond almost instantaneously to a discrepancy between the rudder's actual position and the position which is indicated by a computer simulation. If the discrepancy is greater than a preset value, the system sounds an alarm within two or three seconds. "The system is independent of the ship's steering control system," according to Henry H.
Johnston, marketing manager for Sperry's marine steering gear program. "It uses two basic signals— rudder order and rudder angle— provided by separate transducers on the helm and rudder. If the ship already has a separate rudder angle indicator system, it can be used to provide the rudder angle signal. With automatic steering, the autopilot computer output is used as the rudder order signal." Mr. Johnston said that the U.S. Coast Guard is currently studying proposals to require a steering failure alarm system on all ships over 20,000 gross tons operating in U.S. waters. For additional information, write to Henry H.
Johnston, Sperry Division, Sperry Rand Corporation, Great Neck, N.Y. 11020.