A hydraulic oil system is used in CPT thrusters as the pitch is controlled by means of that unit. Sub-units assembled on an integrated hydraulic power pack (HPP) prepare and distribute oil inside the thruster. On the HPP tank there are built-in pump aggregates, oil filters, block valves, flow and safety valves and controlling tools.
The system of gravity lubrication is applied in thrusters of the types CPT and FPT. The main function of the system is to supply oil to the thruster casing and retain overpressure inside the thruster in relation to water outside.
For vessels where there is a limitation in topping a header (gravity) tank, i.e. on offshore vessels, a pressurized lubrication oil tank is preferable.
