Hydraulic steering - what does this check valve do?

[Keith-i]

I'm considering upgrading the autopilot (a Raymarine S1 which bluntly refuses to follow a plotter route for more than a few seconds) and have started doing a bit of research on compatability with my existing setup. When we got the boat (second hand) it already had this check valve in the lines between the autopilot pump and the helm, though I think it might have been a legacy of an even earlier Cetrek a/p. Is this to protect the autopilot pump from back pressure from the helm or is it vice versa to prevent the a/p pump feeding pressure back to the helm? Do I need it with a modern a/p pump?

 

[jfm]

You don't need it in a modern a/pilot system. The hydraulic hoses from the pump's port/stbd outputs just T into the steering wheel port/stbd hydraulic lines (down stream of the power assist pump if any) that go to the tiller steering ram, without any check valves to prevent "back pressure" created by either the autopilot electric pump or the steering wheel pump.

Likewise there is no check valve in the return line (which you don't seem to have in your picture anyway).

All that said, if the two steering wheel hoses top/left in your picture won't reach the new power steering pump, it might work ok if you keep the check valve. But hopefully the hoses have enough slack to reach the pump, as seems to be the case, or you can move the new pump to left of your picture, so you can throw away that check valve unit.

 

[Keith-i]

Thanks for the reply @jfm. Indeed there is more than enough slack in the hoses to reach the pump position so that is not an issue. Now the question as to whether to go for the Garmin Smartpump v2 or GHP 1.2 pump.

 

[jfm]

I haven't done a side by side comparison but about 2 years ago I fitted the Smartpump and the Reactor thing to my then 8 year old boat, and it was a piece of cake to install. It worked much better than the previous a/pilot (a 2010 era Garmin) in that it held a straighter course with zero fishtailing. So if in doubt get the smart pump and Reactor, imho

 

[ChromeDome]

WHIW: When I looked to source an AP system, the response from sellers that offered more than one possible pump was, "You need the larger" (except Raymarine, who didn't answer at all).
Despite giving them all sorts of info and details about wheel pumps, number rotations from lock to lock and then some, they apparently didn't know and pushed for the most expensive (double ££s) pump.

Simrad offered a consultation with a tech staff member, meeting up at a dealer's shop. He agreed that the less expensive one would do the job, but also had a special offer: The larger pump & accessories "without original boxes" at the same price as the larger one.

Made my day and the AP has worked flawlessly since fitting.

 

[PaulRainbow]

Thanks for the reply @jfm. Indeed there is more than enough slack in the hoses to reach the pump position so that is not an issue. Now the question as to whether to go for the Garmin Smartpump v2 or GHP 1.2 pump.

If the pump you have works, there is no need to change it. You can get a Garmin core pack that works with 3rd party drives. So you could use your existing pump or one from somewhere else, such as HyPro.

I fitted such system to my own boat last year and it works just fine with the old Cetrek pump.

 

[Keith-i]

Thanks for the comments. I saw the Garmin core pack option which I might well pursue on the basis I can always add a new pump at a later date if needed. I’m guessing I could probably remove the valve block as it stands on the basis it sounds like it probably wasn’t even needed for the current Raymarine setup.