Power Boats | Octopus Autopilot Drive Systems

Power Boats

Powerboats have 2 main types of steering system - hydraulic and mechanical.  Both of these systems can be either manual or power assisted.  The most popular mechanical systems are based on push-pull cables with either a rotary style helm unit or a linear style (rack and pinion) helm unit. 
Note that mechanical systems based on rotating shafts with chains and sprockets etc. do exist.  It is difficult to fit a Drive Unit to these systems, and they require a high degree of customization.  Octopus does NOT offer any Drive Unit solutions for these systems.
Hydraulic Steering
Manual:  The Drive Unit is a hydraulic pump that is plumbed into the hand (helm) steering system.  There are 2 types of pump used; the most popular is the reversing pump, the other is a continuous running pump.  The pump is sized to match the required hard-over to hard-over (HO-HO) speed of the steering cylinder(s), which is typically specified by the manufacturer of the Autopilot Course Computer.
Power Assisted:  The Drive Unit is a hydraulic pump that is plumbed into the hand (helm) steering system.  In these systems; the hand steering operates a slave cylinder that in turn activates a valve which controls the power steering.  The slave cylinder tends to be of small displacement, so only small reversing pumps are required on these systems.
Mechanical (Cable) Steering: (push-pull cable systems only)
        Manual:   There are 2 approaches to adding a Drive Unit to a cable steered boat.
- Install a Drive Unit at the dashboard. Replace the existing helm with a suitable Drive Unit (Type S or T)
- Install a Drive Unit in the engine bay. Add a Drive Unit (Type R) and connect it to the steering system with a second steering cable and connection kit.
Details on these options are provided below.
      Dashboard: When considering adashboard solution; the main criteria are:
- Space behind the dashboard – is there enough space to accommodate the Drive Unit?
- Access to the area behind the dashboard – access is required to install the Drive Unit.
- Is existing helm ‘rack’ or ‘rotary’ – Octopus Drive Units are based on rotary helms and can accept steering cables designed to fit rotary helms from most of the major helm manufacturers.  If the original helm is a ‘rack’ type; the whole rack and steering cable must be replaced with a rotary steering cable.
- Is existing helm a ‘NFB’ type (no feedback)? –There is an accessory available for the Type S (only) that simulates the benefits of the ‘NFB’, otherwise Octopus does not support the NFB feature.
      Engine Bay:  When considering an engine bay solution; the main criteria are:
      - The existing steering system MUST be capable of being back driven.
      - This means that it is NOT possible to add Type R Drive Unit to a vessel that has an existing ‘NFB’ helm.
      - There must be a suitable location to mount the Drive Unit.
Power Assisted:   Stern Drive Steering Systems with higher horsepower engines are usually power assisted.  Pressurized oil is supplied by an engine driven pump to the steering cylinder, which is controlled by a servo valve driven from the helm via a push-pull cable.  When considering Power Assisted steering systems the main selection and installation criteria are the same as for Manual steering systems, with possible installation options at the Dashboard or in the Engine Bay.