The L/B Myrtle differs from other liftboats in that it is equipped with a bow thruster and controllable pitch propellers for greater manoeuvrability and pinpoint positioning of the huge legs with oversized pads on the ocean floor. The vessel can maintain jacking speed and manoeuvring while simultaneously holding a precise position. It can jack with a full pre-load and the pre-load system has quick acting stainless steel dump valves.

The 137.5ft long L/B Myrtle has a 92ft beam and a hull depth of 13ft. Its three legs are 6ft in diameter and constructed of 1.5in wall thickness high strength steel.

Power is supplied by two Caterpillar 3512 diesels developing a total of 3,000bhp. They drive Berg controllable pitch propellers through Reintjes reduction gears.

Electrical power is produced by two 190kW generators driven by Caterpillar 3306 diesels, while a 350bhp hydraulic motor drives the bow thruster.

The Hydraquip jacking system is designed using the latest hydraulic and computer technology to accurately control the leg position. The programmable logic controller provides all jacking system logic, safety interlocks, leg position and alarm monitoring.

The hydraulic system incorporates a three speed jacking system that allows leg tagging at 10ft/min, normal jacking at 4ft/min and pre-load jacking at 2ft/min. The jacking system has counterbalance (holding) valves at each motor for pinion isolation. All jacking system pressures, system status, temperatures, alarms, and operation manual are displayed on a liquid crystal plasma touch screen.

MJ Information No: 17436