Raymarine Type 3 Hydraulic Pump, ACU-400 Compatible, 350-500cc Rams

Overview

The Raymarine Type 3 Hydraulic Pump is a reversing hydraulic autopilot pump for boats with hydraulic steering systems and steering ram capacity from 350 to 500 cc, equal to 21 to 30.5 cubic inches. It connects into the hydraulic steering lines so a Raymarine autopilot can move steering fluid and control the rudder or drive while the vessel remains under normal manual steering when the autopilot is not engaged.

For fit decisions, the key checks are ram capacity, system voltage, ACU compatibility, and mounting space. The Type 3 range is available in 12V and 24V versions, works with ACU-400, uses 1/4 inch BSPP hydraulic ports, and has an IP67 motor rating for below-deck marine installations.

Key features

• Reversing hydraulic pump for Raymarine autopilot systems on boats with existing hydraulic steering.
• Type 3 sizing supports 350 to 500 cc steering rams, equal to 21 to 30.5 cubic inches.
• Available in 12V and 24V DC versions so the pump can match the vessel’s electrical system.
• Works with Raymarine ACU-400 for Evolution autopilot installations.
• Peak no-load flow rate of 3100 cc/min, equal to 189.2 cubic inches/min, for Type 3 hydraulic steering response.
• Compatible with single or double-ended rams, balanced or unbalanced cylinders, and pressurized reservoir systems.
• Motor has an IP67 rating and the pump is protected for use in engine compartments.
• 1/4 inch BSPP ports and M6 mounting holes support hydraulic installation planning.

Variants

This Type 3 pump range is offered in two electrical versions. The hydraulic application stays the same: a Type 3 reversing hydraulic pump for steering rams from 350 to 500 cc.

The part number changes with system voltage. The voltage must match the boat’s DC supply and the autopilot ACU.

• M81122: Voltage 12V. This version is for 12V DC systems and is listed for use with ACU-400.
• M81124: Voltage 24V. This version is for 24V DC systems and is listed for use with ACU-400.

Installation and setup

Install the pump below deck on a substantial structure where the hydraulic pipes are not placed under strain. It can be mounted in any orientation, although a motor-up position is preferred when the unit is mounted vertically. The location should be clear of spray, possible immersion, excess heat, fumes, and areas where flooding is likely.

The pump should sit as close to the steering ram as practical and level with or above the ram to help keep air from collecting. All pump ports are 1/4 inch BSPP, with the reservoir line routed in a continuous rise to the helm pump or reservoir. The reservoir port must remain connected and should not be plugged.

Compatibility and fit

Before installation, confirm the hydraulic cylinder ram volume from the steering system documents or from the cylinder model. This pump is the Type 3 size, so it is not the right hydraulic match for smaller ram capacities below 350 cc or larger rams above 500 cc.

It is a good match for boats already using hydraulic steering where an Evolution autopilot is being added or serviced, including cruising and fishing vessels with steering gear in the Type 3 ram range. For mechanical steering, it can be used only as part of a secondary steering ram installation.

Electrical and hydraulic integration

The pump motor connects to the autopilot drive output through the course computer or Evolution ACU. Keep power off while wiring, keep the pump cables and ferrites intact, and maintain separation from VHF, SSB, radar, and other transmitting equipment where space allows.

Hydraulic cleanliness matters on this installation. Use hoses and fittings with pressure ratings that meet or exceed the steering system requirements, avoid PTFE tape or pipe sealing compound on the hydraulic ports, and bleed all trapped air from the system after the pump and the rest of the autopilot have been installed.

Maintenance and care

After installation, inspect the mounting hardware, pipes, and cables periodically. Loose mounts, worn hoses, or damaged wiring can affect steering feel and autopilot performance, especially on boats that see vibration, heat, and saltwater service.