(DG) Type 3 Hydraulic Pump Mounting

[Derek - Raymarine - Moderator]

Hi Win,
Thank you for your enquiry.

We would not advise mounting the pump on a vertical axis for several reasons.

The Hydraulic oil in a steering system will always contain microscopic air bubbles, these will coalesce and create larger air bubbles and will lead to cavitation within the pump - causing loss of pressure as well as creating excessive noise and possible overheating. It could also lead to the shaft oil seal running dry,hardening and then subsequently leaking.

The thrust bearing of the pump is not designed to operate in this orientation and will wear excessively leading to possible premature failure.

We would always recommend the pump is mounted with it's axis horizontal and to be completely correct, mounted fore and aft, (which incidently is the convention on all rotating machinery on larger ships), although this is not entirely necessary on smaller vessels.

The pump should always be mounted on a horizontal surface with the pipe connections exiting at the top, (so do not mount horizontally with the pipes exiting the pump body from the side) . Mounting the pump so that the pipes are connected to the top of the pump body will allow any air built up inside the pump to be expelled back to the reservoir and not interfere with the operation of the pump.

Regards