The photograph shows two VJ type calipers installed on the aft end of a marine gearbox. Manufactured by Allen Gears in the UK, the triple reduction gearing transmits 11,450 HP (8542 kW) at 6556 rpm from a marine gas turbine.

Designed for a reduction of 58.53:1 the gearbox output drives a constant pitch propeller at a speed of 112 rpm.

The two VJ calipers, acting on a 1600 mm diameter disc, are activated pneumatically from a 70 bar pressure supply.

Two stage braking is employed, whereby air pressure initially forces the pads to touch the disc. Hydraulic pressure then takes over to complete the braking cycle, which is designed to develop a total braking torque of 240kNm.

The required hydraulic pressure of 140 bar is produced through a 20:1 air to oil intensifier mounted within the brake control system. It acts on the caliper piston through a secondary feed supply line.

The main propulsion gearbox was built for a 45,000 tonne bulk carrier constructed at Whyalla Australia. It is part of BHP's fleet and is used for the transportation of Australian iron ore.