An Octopus Hydraulic Linear Actuator is a simple, effective way to drive the
rudder on a boat equipped with a mechanical steering system. The linear actuator
is an assembly of an Octopus reversing pump and a marine hydraulic cylinder.
This assembly is mounted on the rudder tiller-arm or quadrant. When the
autopilot is not in use the cylinder runs freely along with the rudder. When the
automatic pilot is in use a solenoid valve on the actuator closes and locks the
cylinder. Steering signals from the pilot are now fed to the D.C. motor, which
drives the pump to move the cylinder back and forth. De-energized, the solenoid
valve immediately disconnects the automatic pilot from the rudder. The actuator
has a small translucent oil reservoir, making it easy to check fluid levels.
These actuators have only five moving parts. Mechanical simplicity gives our
product reliability and ease of service when compared to complicated gear and
screw actuators, making our units a favorite for offshore mariners. These
actuators are shipped from our factory completely filled with oil and require no
Octopus offer a full range of powerful, low current consumption hydraulic
linear drives designed for long passage making. An independent comparison by the
University of British Columbia* showed that Octopus piston pumps are three times
more efficient than a gear pump and can be expected to halve the battery
consumption when compared to a competitorís unit, therefore doubling the
effective range of the autopilot on one battery charge.
The drives are available either with the pump mounted on the cylinder or
Adjustable Flow Rate
A linear drive that does not have variable flow (unless dedicated to a range
of yachts) will be operating either too quickly or too slowly in 90% of cases.
Autopilot manufacturers get around this problem by adjusting the output to the
pump to compensate. However, this either forces the pump to operate for longer
periods of time which increases power consumption and wear on the parts, or the
pump will operate at high pressure for short periods of time - also putting
unnecessary strain and wear on the system.
Octopus variable flow reversing pumps precisely control the speed of the ram,
reducing battery consumption, pressure, strain and wear on the hydraulic system.
Average Current 4-6 amps
Max Current 19amps
Cylinder Bore: 38mm
Variable Flow Rate: 600cc-1.2 litre/min
Hardover Time(Suggested): 14-16 sec
Max Rudder Torque: 1,200Nm/10,600lbin
Peak Thrust: 400Kg/882lbs
Max boat Length: 18m/60'