I'd like to hook up the other power steering pump.
I have this in the boat, would it be as simple as hooking up the pressure line to that port.. and figure out where the return line goes?

Dan, if you want to operate both PS punps at the same time, you need a sinple check valve system from each pump source where it joins into the single pressure feed. You also need to have a common resrvoir.

Alternative solutions: have valves setup to swith feeds if one engine or pump fails...to run the other one. (One would be just freewheeling until needed)

I'm looking into running a Volvo car Elec Power Steering pump as a backup.

I would say it depends on if that box has check valves to prevent fluid from flowing backwards into the other pump. And then there needs to be a way for the fluid to get back into both pumps.

You would need this IMCO valve Search

I bought a valve for dual helm, I suppose I could incorporate it .. I did find that valve but hoping I could save a few bucks.

I don't think it would be "possible" to have an effevtive diverter for low pressure return to the invidual reservoirs.

Meaning...the solution could be more complex than it's worth.

Have you gpt Saginaw GM style PS pumps with reservoir attached?

Reservoirs need to have room for an expansion capability. With external hyd cylinders that change volume, the fluid needs to go somewhere.

Maybe...if you had a reservoir that was designed to opererate 'full', and it had a low pressure hose that fed the 2nd PS reservoir, containing sufficient expansion. Any operpressure in Res 1 would push out to Res 2. You would require a reasonably large inter-reservoir connecting hose.

The PS setup is just a basic hydraulic system.

ICDEDPPL;I bought a valve for dual helm, I suppose I could incorporate it .. I did find that valve but hoping I could save a few bucks.[/QUOTE]

Get the IMCO valve. It is the cheapest way to go. Common reservoir for both pumps. Putting that system on my Cat now.

I think this would be the diagram that valve.

I had ChatGTP draw this up.. I`m not sure it`s accurate . I would need to know how the check valves need to be oriented.

This looks correct other than fluid returning to the pump from the coolers. It should return to the reservoir

This does not look correct at all. Looks like chat gpt thinks your trying to use a single outboard steering cylinder for both m6 drives