STEERING SYSTEMS L.S. hydraulic steering system

Small boats usually apply L.S. hydraulic steering system, which is made up of wheel, manual pump, tubing, cylinder, etc. The wheel is mounted on the shaft of manual pump, while the manual pump and cylinder are connected by plastic tubing. The cylinder is connected by tiller arm and rudder, when operating the manual pump, the hydraulic oil will go through tubing from one side of the cylinder, and return from other side of the cylinder, so as to displace the piston of cylinder and complete the process of steering.

Cylinder:

The cylinder is the dictating element towards the selection of a system as it gives the power to the steering system.

Manual pump:

The manual pump is an axial piston pump which makes it possible to suck and force back the oil contained in the circuit when the wheel is turned. Its cubic determines the number of turns required for a lock to lock manoeuvre. The pump is fitted with a lock valve which prevents rudder or motor movement when the helm is not operated. Some models are fitted with pressure relief valves which protect the circuit against abnormal pressure increase.

Tubing:

The tubing is used for hydraulic transfer. The tube diameter is calculated in function of the pump cubic capacity. Maximum efficiency is achieved with inflexible tubing, however flexible tubing maybe used for torque levels not exceeding 100Kpm

Working principle

(1) Manual pump

(2) Tubing

(3) Cylinder

(4) Tubing

(5) By-pass valve

(6) Power pack

(7) Tiller arm

When the helm is turned to starboard, the pump(1) sucks the oil form the port circuit(2) and pushes it back into the starboard circuit(4), thus driving the cylinder rod(3) which in turn displaces the rudder or motor. The cylinder body (3) is fixed to the boat.

Performance Parameter of L.S. Hydraulic Steering System: