Well I finally got up the nerve and did it. Cut TWO six inch holes in the top of the diesel fuel tank on my 1979 H37C. After being towed with a fuel problem last season I just had to know what was in there. And guess what, there is NO screen on the pickup tube. That tube comes in the side of the tank, near the middle, goes down to the bottom and then runs along the seam all the way to the forward, inside corner. As you can imagine from the shape of the hull that is the lowest and deepest part of the tank. Except for a very light, black powdery substance the tank was clean. A swipe with a rag took the black stuff right off. The tank is very solid, at least 5/32” and maybe 3/16”. Used a good metal blade in a sabre saw and worked slowly. I cut the first hole 34” from the forward edge and 9” from the inside edge. I wanted to be close to where the pickup came through so that I could see how that was done. I knew there was a baffle but did not know where. That section of the tank is kind of shallow and I can reach most of the bottom and sides up to the baffle. Because of the baffle I could not see the end of the pickup tube so knew I had to cut another hole. The baffle is 18” from the forward edge, it’s at the point where the tank has an inward offset of about three inches. So I cut a second 6” hole, just about four inches from the fuel gauge. Now I can clean the entire tank although it really looked good. There was still about a quart of diesel in there after I pumped her out last Fall. But no detectable water. So the question, why did it starve for fuel and require a tow? Why did pumping air back through the line to the tank clear up the problem? Maybe the pressure cleared the vent? Now I have to go and make two covers. Tom, your guy was probably right. No reason to get in there.