Boat lift plumbing?

Hi all, I have been helping a friend on the lake who has a hydraulic boat lift. The plumbing needs to be redone as it currently has no labels and tons of valves for different operations. When the owner’s husband passed a couple of years ago, he took the operational knowledge with him. She is not mechanical so therefore needs something simple to remember.   Anyone have basic rules or piping schematic so that I can make sure I don’t miss anything while re-piping?

Water,   the pump sits on the dock, and draws water from the lake.   I know that I need a supply/pressure line to the hydraulic cylinder in the lift, and also need to be able to release the water from the cylinder when the boat goes back in the water.    I also want to plan ahead for winterizing and priming as the lift and pump stay plumbed year round.

My buddy's lift on Lake Washington is a water lift....If you get stuck I could go and and see how it's setup. I seem to recall it being pretty simple. Inlet draws from a hose bib and feeds a pressure pump...that leads to a two way toggle valve - one side allows high pressure to the cylinder and the other side releases pressure and the water just drains to the lake.   Don't think there's much more to it than that. It's a pretty old (and simple) lift so it's possible newer ones have more to them.

My lift is a 12v oil hydraulic so I'm less familiar with with water types.

I'm not on the lake so getting an actual photo would take a couple of hours drive time.    This one looks very similar, including the cylinder color and approximate size, so it could be the same brand.    





Aqualift Website

Thanks Ultra.   I think that is how it works too, I was thinking that I needed to make some provision for winterization/draining on the valving system, along with a way to prime the pump in the spring.   Another buddy of mine was also working on it before we all got told to work from home... I think he has a plan, so I'm in a holding pattern for now.   original valving got ripped out during a dock repair, so hopefully we'll get it corrected before the lake gets all the way filled up.