Pump Size

[252gw]

I have a 2003 GW 330 Express that we want to install the AP 711, The boats motors each have a sea star HC5358 Ram @ 8.34CC. My question is do I need a pump to cover 8.34 or 16.68?
Thanks

 

[Deep Blue]

252gw,

The output flow rate of an electric pump set determines the maximum speed of the rudder. Under normal conditions a rudder speed of 10 to 15 seconds will provide the best steering results for most Furuno autopilot systems. First, determine the volume of your steering cylinder. This information is usually indicated in the instruction manual of your steering system, typically found at the back of manual.

You must calculate the volume of your cylinder manually you can use the following formula:

Volume = L (D2 -d2) π÷4

Where: L = length of stroke of cylinder D = internal diameter of cylinder d = diameter of piston rod π = 3.14 (Pi) The rudder speed, hard over to hard over (HOH), is determined by dividing the volume (cu in) of the cylinder by the output of the pump set (cu in/sec).

- Deep Blue

 

[252gw]

Thank you deep blue, my math is rusty, I have two rams with the dimensions below do I double the pump size for one?
SeaStar bore shaft stroke seal volume cc
SeaStar Pivot Mount
(HC5358) 1.375 (35) .75 (19.0) 8 (203) HS5157
Volume 8.34 (136.6) N/A

 

[Deep Blue]

252gw,

One easy way is to try to find out what the Hard Over to Hard Over time that is recommended for your Seastar Steering System.

- Deep Blue