Charlz, I understand in regards to access to the fresh water tank. On mine, it appears they installed the tanks before they installed the liner. I would have to cut out the V berth deck to get either of mine out. If your holding tank is sound other than the additional hole installed by the DPO, you may want to consider patching the hole. I know they make a plastic tank repair kit for RV type tanks that may work. I agree all of the hoses need replacing. I need to do that on mine too. It's on the to do list. As for the water hose type fitting on the deck, and the way it is plumbed to the waste tank, it was probay set up that way so that the tank could be flushed with clear water as it was being pumped out. With the seacock closed, suction on the clean out line would empty the tank, and with clean water bring injected into the tank, probably work well to clean out the tank. From what I saw in the video, that open port in the chain locker does look like your fresh water tank fill. It also looks like your waste tank vents to the chain locker too. At least I think it does from the small line T fitting on top of the tank. Waste tank venting straight into the water tank....Yuck! The waste tank vent should be outboard and away from the fresh water inlets. Peggies book is good. I purchased it a few months ago in prep for my waste tank re-plumb.