Hydraulic Steering Systems

Raymarine Evolution pilots connect to hydraulic steering systems using a rugged hydraulic pump matched to the capacity of the hydraulic steering system.

If your system is hydraulic...

You'll need to find out the size (in cc) of the hydraulic cylinder ram(s) mounted to the rudder or inboard engined boats, or to the drive unit on outboard engined boats. Your steering system documentation will have this information.

  0.5ltr Hydraulic Pump | Raymarine Type 1 Hydraulic Pump | Raymarine Type 2 Hydraulic Pump | Raymarine Type 3 Hydraulic Pump | Raymarine Constant Running Pump | Raymarine
Drive Type Type 0.5 (12V) Type 1 (12V or 24V) Type 2 (12V or 24V) Type 3 (12V or 24V) Constant Running Pump (12V or 24V)
Part Number 12V: E12139 12V: M81120 24V: M81119 12V: M81121 24V: M81123 12V: M81122 24V: M81124 12V: E12171 24V: E12172
Vessel Displacement Does not apply here. The drive unit is matched to the ram capacity of the steering system
Ram Capacity 50cc-150cc
80cc – 230cc
230cc – 350cc
350cc – 500cc
500cc - 1200cc
(30.5in3 - 73in3)
Maximum Stall Pressure at 12V 50bar (750psi) 100bar (1450psi) 80bar (1160psi) 57 bar (827psi)
Peak Flow Rate (No Load) 1000cc/min (67in3/min) 2000cc/min (122in3/min) 2900cc/min (175in3/min) 4500cc/min (274.6in3 / min)
ACU Used ACU-100 ACU-150 (12v)
ACU-400 ACU-300


  • In some systems with dual steering rams in parallel, cylinder capacity is the total of both rams. Rams in series only require single capacity valve. Hydraulic steering systems with steering rams over 500cc require our larger constant running pump used in conjunction with the relevant ACU - contact Raymarine for details.
  • An authorised Raymarine dealer is best suited to installing a hydraulic autopilot system.
  • Type 0.5 suitable for Volvo D4/D6 Sterndrive applications.