NAUTECH 3.1/M-90 hydraulic steering package for outboard motors under 300 hp. The package contains a set of 9-meter hoses, a connector pressed into one end of the hoses. Also includes connectors that can be easily attached to the free end of the hose yourself. Steering 5.1 revolutions, with full stroke of the cylinder.

Contain:
- 1 pc UP25F hydraulic pump, output is 25 cm³, working pressure 70 Bar
- 1 pc UC128-OBF/1 hydraulic cylinder, volume 128 cm³, stroke 185 mm
- 2 pcs 9 m KIT OB/M-90 Ø 5/16” ID hydraulic hose
- 2 pcs 5/16” ID hose connectors
- 2 l of hydraulic oil

Good to know when choosing a hydraulic control system:

The hydraulic control 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 the oil up 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 non-return valve that prevents the oil from returning the same way. This allows the use of multiple rudder control devices. Cylinders are either balanced or unbalanced. In a balanced cylinder, the same number of turns of the rudder moves the rudder from the center position in either direction. Unbalanced cylinders have two chambers with different volumes. Thus, a different amount of rudder revolutions is needed to achieve the desired steering movement in different directions.

ULTRAFLEX manufactures different pumps with different capacities (moved amount of oil in cm3 per turn of the rudder) for different uses. When choosing a pump, the oil volume of the cylinder must be taken into account. The number of turns of the rudder to starboard and port depends on the ratio of cylinder volume to 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 in order for the rudder to move from one extreme position to another. When connecting two cylinders together in parallel, the volume of the cylinder must be multiplied by two. Applications where the number of revolutions of the rudder falls below four are not recommended, because the steering forces become excessive. Applications where the number of turns of the rudder is more than eight are also not recommended, because the steering becomes too slow to react. Maximum working pressure is 7.0 MPa (70 bar) (1000 psi).