Autopilot Hydraulic Pump Size?

[jimmy_the_builder]

Not sure if its the system you use or not Jimmy, the garmin system is one size fits all pumpwise....
But, its also double the price. I think about 2.5k.

Mine's a Raymarine. Personally, I think it's shoite but that's more to do with the aged course computer I think, than anything to do with the hydraulics.

 

[Robg71]

Ive been tempted to fit one to mine. Only thing stopping me is being tight.

 

[CHI]

The kit sounds very good. All is fine but is the AC100 man enough for a 38/40 ft boat of 8000KG displacement? All other other components are fine for d4/d6 usage. Definntely a 0.5 pump required.

 

[Whitelighter]

The kit sounds very good. All is fine but is the AC100 man enough for a 38/40 ft boat of 8000KG displacement? All other other components are fine for d4/d6 usage. Definntely a 0.5 pump required.

Apparently it is.

The VP DPH system requires very little additional pressure as the AP effectively runs of the back of the power steering pressure.

 

[CHI]

Thanks Whitelighter for info.

I have a Sealine S38 with twin D4 260,s running through DPH drive legs. I might also purchsse this system . Please keep us informed of any other info.

Best Wishes

Keith
CHI

 

[spannerman]

Type 1 is a fairly common size, it's what I just fitted to my boat (sailing, though!)
http://www.raymarine.eu/view/?id=579


Shirley, the autopilot brain compensates for the speed you're travelling at? My ageing Simrad/Robertson has low and high speed rudder turning speeds, which it calibrates during the sea trial after installation/modification.

The size of the pump allows the AP to turn the rudders faster and against more force, but it doesn't mean it has to.

Ther AP does take into account speed, but on a D4/6 setup the servo pump (hp) operates the steering cylinders and the helm pump (lp) just operates a shuttle valve on the high pressure side, the AP pump is plumbed into the low pressure system, so if you have a pump with more than .5 ltr capacity it operates the shuttle valve too quickly and gives you very aggressive steering response, which can't be tuned out.
Doing the autolearn with the wrong pump is definitely scary.

 

[jimmy_the_builder]

Ther AP does take into account speed, but on a D4/6 setup the servo pump (hp) operates the steering cylinders and the helm pump (lp) just operates a shuttle valve on the high pressure side, the AP pump is plumbed into the low pressure system, so if you have a pump with more than .5 ltr capacity it operates the shuttle valve too quickly and gives you very aggressive steering response, which can't be tuned out.
Doing the autolearn with the wrong pump is definitely scary.

Apologies for reviving this old thread. Spannerman, you say here that an autopilot pump that is too big gives you an aggressive steering response that can't be tuned out; how does this manifest itself? 'S'-ing?

Separately, does anyone know the actual capacity (in cc) of the DP-H steering ram?