as of 28/09/2021


EU Shipping Guide

Our website is fully operational and all orders will be processed and dispatched as promptly as possible. We are experiencing delays in sourcing some products from various manufacturers. In the event of any significant delays in delivery, we will notify you.

Shipping to EU Countries is now re-instated. Due to VAT rules imposed by the EU, there is now a minimum order value of £135 ex vat and excluding shipping for orders to be processed.

All supplies to EU customers are now Excluding VAT, this is now charged locally by the courier, on delivery. Please click here for our latest update

Autopilot Reversing Pump Sizing

Posted by Yachtbits Blogger 14/02/2019 0 Comment(s)

It is important to select the correct size pump as it directly influences the ability of the autopilot to steer the vessel.


An autopilot drive will need to give a compatible Hard Over to Hard Over time to suit the vessel type (Or as specified by the autopilot manufacturer).


The HO to HO may be faster on lightweight planing craft / yachts and slower on displacement power boats / long keel
or heavy yachts.


Note if the pump is too large, the vessel may over steer and will use more power, too small and the autopilot may struggle to maintain a course.


To use the table below you will need to know the volume of your steering cylinder. Select the HO to HO you require. Follow the column down until you approximately match your cylinder volume. Then select the pump on that row.


Note if your cylinder has a smaller volume, it will have a faster HO to HO. If it is larger, it will have a slower HO to HO. “ HO to HO” Is the time that the pump takes to drive the rudder from full port to full starboard. “Dock side” (no flow over the rudder).


If your existing ram is marked in Cubic Inches (cu in.), multiply this number by 16.39 to get the approximate cc volume. 


Hydraulic Autopilot Reversing Pump Sizing Chart