I have a 1998 40 DA, it came with a pigtail that plugs into the 12v power adapter at the helm. I hook that up to a 12 v jump box and it back feeds the hatch lift.
Have 1998 40 DA with diesels. Previous owner hacked up the old to get it out. Replaced with Isotemp Slimline which slides right in. It’s only 4 gallons, but you still get one long shower out of it. 2nd person has to wait about 30 minutes.
Can’t see what they did but if anyone is looking for carpet get samples from your potential source first. In my opinion, Corenthian Marine Aqua Mat is tops.