I recently installed a new pressurized water pump and redid some of the plumbing in our new-to-us Kingscraft 35. We hadn't been using the old system at all. When things seemed ready, we filled the tank for the first time since we've had her. It all seemed to go well. We filled until water came out the vent (and a little slopped out of the fill fitting and onto our deck too, heh).
I then flipped on the pressurized water, and again, everything seemed just fine. Yay, water at the sink finally! I pumped it dry... with the idea of putting in several fills and emptying them. As I was doing this, I started timing how long it took to pump the water out of the tank. Based on our pumps rated max flow, it seemed like we were pumping the water out faster than we should. So I did a little more rigorous testing, and I've discovered that we can only pump out about 61-62 gallons out of our tank.
So here's the issue. All the specs for this boat I can find say we should have a 125 gallon tank. The tank is built in to the boat, in the keel. There is no inspection port... there are just 3 welded-into-place pipe nipples sticking up out of the top of the tank. 1 for the fill, 1 for the vent, and 1 for the pump intake.
So I see three possibilities. The pump intake could have a hole in it about halfway up inside the tank. The tank has a *whole lot* of buildup. Or for some reason our tank was made with only half the rated volume. Anyone know anything about these boats? I'm thinking about cutting an inspection port into the top of the tank, but it's not a job I really want to do if I don't have to.