HYDRAULIC STEERING OUTBOARD ENGINES <150hp

Good to know when choosing a hydraulic steering system:

A hydraulic steering system consists of a hydraulic pump and a cylinder. These are connected to each other by pipes or hoses. Turning the rudder pressurizes the hydraulic pump, which forces oil through the pipes to the cylinder and from the cylinder back to the pump. The movement of the cylinder is transmitted to the rudder or sterndrive. The pumps have a check valve that prevents the oil from returning back the same way. This allows the use of multiple rudder steering devices. The cylinders are either balanced or unbalanced. In a balanced cylinder, the same number of rudder revolutions move the rudder from the center position in both directions. Unbalanced cylinders have two chambers with different volumes. This means that a different number of rudder revolutions are needed to achieve the desired steering movement in different directions.

ULTRAFLEX manufactures various pumps with different capacities (moved oil volume in cm3 per rudder revolution) for different applications. When selecting a pump, the oil volume of the cylinder must be taken into account. The number of rudder revolutions to starboard and port depends on the ratio of the cylinder volume to the pump capacity. Example: If the pump capacity is 20 cm3 and the cylinder volume is 94 cm3, the formula is as follows; 94 divided by 20 equals 4.7. Thus, the rudder must be turned 4.7 times to move the rudder from one extreme position to the other. When two cylinders are connected in parallel, the cylinder volume must be multiplied by two. Applications where the number of rudder revolutions is less than four are not recommended, as the steering forces will increase excessively. Applications with more than eight rudder turns are also not recommended as the steering becomes too slow to respond. The maximum operating pressure is 7.0 MPa (70 bar) (1000 psi).