Automated cargo securing system enhances offshore supply vessel safety

1 May 2006

The Rolls-Royce Automated Sea Fastening System (ASFA) in operation

Rolls Royce has developed an automated cargo securing system for offshore supply vessels that is designed to significantly reduce the risk of injury to crew members.

Whereas most ship types load and unload cargo in relatively calm harbours, offshore supply ships frequently have to work in adverse weather conditions. Traditional deck lashing systems have tended to involve more manual work, and risk, than is desirable on such ships, as the cargo is generally only partially secured once cargo handling operations have begun.

To address this issue, UT-Design has produced the patented Automated Sea Fastening System (ASFA), which has recently been tested under demanding conditions onboard the Farstad vessel Far Star. The trial has in fact been so successful that its has recently been confirmed that four vessels destined for long term contract with Norsk Hydro will incorporate the new ASFA system. In addition, two vessels being built for Farstad to a new UT-Design specification, the UT 751 E, will also have ASFA as part of their onboard equipment package.

ASFA features a series of tracks, which run transversely the full width of the deck and which are positioned at intervals along the full length of the deck. As the tracks are set flush with the wooden decking, they cause no obstruction to cargo operations.

Inside each track there is a slider carriage, to which chocks can be attached. These chocks stand well above the deck and are used to position and secure deck cargo, such as containers and pipes. Each slide and its associated chocks can be pulled along a guide track from one side of the vessel to the other by a chain drive. The chain - either a link or roller chain type - runs in a loop from the slide to a drive unit at one side of the ship, back through the guide, around a guide wheel on the other side of the ship, and back to the slide. The hydraulic drive unit can move the slide with a force of between 3 and 30 tonnes, according to specification.

During the loading process, containers are placed on deck and the relevant chocks are then moved singly, or in groups, by remote control to position the containers and lock them against the cargo rail. When the supply vessel is discharging cargo, there is no need for the crew to release more containers than is necessary, and so the remainder can stay securely fastened. Should there be a need to move containers from one side of the deck to the other, the chocks can easily be removed from the slide, the slide moved to the desired position, and the chocks refitted.

ASFA also generates operational safety benefits when carrying pipes, avoiding any need for chocking individual pipes by hand, a procedure that can prove hazardous for crew members. Using ASFA, chocks can be steered to position the pipes as required and lock them securely to prevent rolling.