Mechanical. Like all over the side operations, equipment and system components come under loads due to the action of ship motion and seas. Personnel must minimize time beneath working sheaves and the line of the electromechanical cable leading from the winch to the equipment deployed over the side or stern of the ship. Loads on these systems can be thousands of pounds. You can imagine that a hard hat will not help much if you are hit from above by a 30" diameter sheave like the one we use.
Hydraulic systems are used to drive the winch and to aid spooling of wire onto the winch. Such systems have been engineered to maximize safety but personnel must also avoid these systems while they are working.Electrical. 440 V 3 phase electricity is used to power the Winch and Level wind of the MULVFS during its deployment and recovery. The connection of this equipment to the ship's power supply must be done under supervison of qualified ship's personnel.
When MULVFS is deployed and operating. Power is fed from the ship's supply via an electrical cable from LBNL's control equipment located in a dry area of the ship to the winch located on deck. Between the ship's power supply and LBNL controls there is a mechanical lock out breaker and an isolation transformer. The 'lock out' breaker must be off and 'locked out' prior to connecting or diconnecting the deck cable at the winch.
The mechanical breaker must be off and locked out during all deployment and recovery operations and when the deck cable is physically disconnected from the winch.
The system is protected during operation (while samples are collected)
through redundant use of an isolation monitor/drop out relay and computer controlled relays. Personnel are advised to stay away from the winch and wire