I only have a power steering pump on my Stbd engine. I want to create some redundancy in the system if I lose the Stbd engine.

How much steering is there with no pump pressure?

I'm toying with the concept of an electric power steering pump as a backup. Obviously not as a full performance option, more of a limp home mode running only 1 engine.

Setup would be a manual valved isolation until required. No need for a single reservoir.

Obviously pressures would be lower. But limp mode that should be gtg?

You will have steering, it will feel like a H Farmal pullin a 2 bottom plow..............putting it in a slip on one is a pita

Check. Good analogy...lol.

I don't typical use slips...more a mooring. But even getting on to a launch dock could be a pita.

How does the steering wheel control system work? Is there check valves that keep the steering cylinders locked in place until pressured and relieved?

Looks like there's a lot of EPS...electric power steering options from many vehicles. Volvos being one of the primary donors to perf street cars etc.

Seems like a viable option. Easy mount, and easy plumb. Also makes easy bleeding of the system without running the engines.

Unless you have removed the steering lines try it. The pump in the hydraulic helm is small so it's gonna take a whole lotta turns to maneuver the boat. Even more due to the fact that the steering rams are in parallel, you may want to change that to series but I didn't want too much sensitivity at speed, and had to turn quite a few turns for lock to lock.