Overview

The B&G 000-13902-001 is a Type 0 hydraulic ram drive for autopilot steering on boats with back-drivable mechanical primary steering.

It is a self-contained linear actuator with a hydraulic cylinder, pump, motor, clutch, and reservoir in a sealed, pre-filled unit. It runs on 12 VDC with a nominal 12 second hard-over time, up to 350 kg intermittent thrust, and a maximum stroke of 203 mm (average hydraulic volume 234 cc). The housing is rated IP67, and the specified operating temperature range is -15°C to +55°C.

With the clutch disengaged, the cylinder can move freely with the helm. When the clutch is energized, the autopilot drives the motor to extend or retract the ram for rudder control, and internal relief valves help protect the unit and mountings during rudder strikes or grounding loads.

Key features

• Integrated cylinder, pump, motor, clutch, and reservoir in a sealed, pre-filled unit for simpler plumbing and service access
• 12 VDC drive with nominal 12 second hard-over time and maximum stroke of 203 mm
• IP67-rated enclosure for wet lockers, bilge-adjacent spaces, and washdowns
• Up to 350 kg intermittent thrust with 234 cc average hydraulic volume
• Clutch lets the ram back-drive with the primary steering when disengaged, then locks in for autopilot control when energized
• Typical current draw is 1.3 A at 25% duty (60 kg), with 14.0 A intermittent at 350 kg
• Clutch coil power is 12 W with a DIN 43650 clutch connection (6 to 8 mm cable)

Installation and setup

This actuator is intended for under-deck mounting. Plan the location to keep cable runs short, keep the unit away from heat sources, and mount it above areas liable to flooding. Use a solid mounting surface that can carry the thrust loads, and make sure rudder hard stops limit travel rather than the actuator end stops.

Allow clearance for the full range of movement and for removal of the mounting pin. The supplied tiller bolt is suitable for a quadrant thickness of 12 to 16 mm, with a recommended mounting hole of Ø12.2 to 12.3 mm and an M12 nut torque of 27 Nm. The supplied mounting foot hardware is suitable for mounting to a surface 12 to 24 mm thick, with the four M8 nuts tightened to 17 Nm.

Compatibility and fit

This drive is built for steering systems that can be back-driven, where the rudder quadrant or tiller arm moves freely when the clutch is not energized. Check geometry and clearance through the full rudder arc before drilling, and confirm the ram stroke and linkage position match your quadrant layout and required rudder angle.

The unit’s overall envelope is 101 x 728 mm and weight is 8 kg, so it typically fits best where there is a straight, unobstructed run to the quadrant and enough space to service the mounting pin and wiring.

Electrical and system integration

Power is 12 VDC. The motor direction is controlled by polarity: red lead to positive extends, and black lead to positive retracts. Size wiring and circuit protection for the intermittent current draw, and route cables so they cannot chafe or snag on moving steering gear.

The clutch uses a DIN 43650 connection and draws 12 W when energized. Plan the installation so the clutch and motor wiring can be reached without disassembling surrounding steering components.

Hydraulic fluid and maintenance

The sealed system uses mineral hydraulic fluid in the ISO VG10 to VG40 range (ISO 6743-4 HV). Do not use brake fluid. If service is ever required, use a mineral-based fluid that is compatible with nitrile seals.

Keep the piston rod free from damage and avoid exposing the unit to saltwater spray or immersion wherever possible. If the area is prone to salt mist, regular wipe-downs and checking for corrosion or contamination around the rod and mount points helps keep the steering movement smooth.

Use on board

This ram is a good match for boats that need an under-deck linear drive to automate a mechanical steering system and still want the helm to move normally when the autopilot clutch is not engaged. It suits installations where space is limited but accurate rudder control and quick access to the quadrant area matter.