Rotec Hydraulics has recently completed a major contract to supply, configure and install hydraulic hoses as part of a refit programme for the Royal Navy's amphibious helicopter carrier, HMS Ocean. The latest DEF STD 47-2 Parker Defender hydraulic hoses and fittings were used throughout, providing a unique combination of flexibility, ease of installation and ability to function reliably under extreme operating conditions. With a maximum complement of 1275 and a displacement of 22,500 tonnes, HMS Ocean has been designed to provide amphibious assault capabilities anywhere in the world, with secondary roles including training, anti-submarine warfare and a base for anti-terrorist operations.

The ship is capable of carrying Sea King or Merlin medium support helicopters, Apaches, Gazelles or Lynx helicopters and landing craft, plus a wide range of support equipment for her complement of Royal Marines.

As part of a major refit undertaken recently at Devonport Dockyard, Rotec Hydraulics was commissioned to inspect and, where appropriate, replace many of the existing hydraulic hoses and fittings used throughout the vessel.

These are used extensively on boat davits, forward and aft aircraft lifts, stern and starboard quarter loading ramps and other hydraulically powered units.

Terry Light, Sales Director at Rotec Hydraulics, explains that, 'The key requirements for the new hoses and fittings were reliability and safety'.

'It is essential that the various on-board hydraulics systems function effectively even under the most arduous conditions'.

'For example, the hoses and fittings used on the boat davits are constantly exposed to extreme weather temperatures, strong sunlight and salt water yet have to withstand considerable hydraulic shock and mechanical stress'.

'Similarly, each aircraft lift imposes high dynamic and mechanical loads on the hydraulic systems quickly and smoothly from hangar to flight deck'.

The use of Parker's latest Defender Defstan hydraulic hoses, combined with Parker's stainless steel and passivated zinc fittings, enabled Rotec to produce hose assemblies that are quick and simple to fit yet provide an exceptional level of performance and reliability.

For example, the Defender hoses have a carefully designed three-layer construction, with an inner core manufactured from a seamless oil-resistant synthetic rubber, reinforced with one or more layers of braided or spiralled high tensile steel wire and covered with an outer layer of tough synthetic rubber.

Defender hoses can therefore be used at temperatures ranging from -40 to +100C, with working pressures of between 40 and 500 bar, and will withstand abrasion, weathering and ozone degradation.

In addition, the method of construction ensures low volumetric expansion for rapid, accurate hydraulic response and reduces both the weight of each hose and the bend radius, making hoses easier to install in confined areas.

Rotec and Parker worked closely with the Royal Navy technicians to ensure that the project was completed as quickly and efficiently as possible.

Terry Light adds that, 'Our engineering workshop and ParkerStore in Plymouth was used for all hose and fittings supply, plus assembly and testing, with our engineers completing the installation on-board while HMS Ocean was in Devonport Dockyard'.