Still some sloshing, but not much. Could be another pontoon with water in it. Could be the same one we fixed and I just didn't get it all drained out (hard to believe though given what I did to drain it).
I'll be getting one of those USB inspection cameras and looking in them all...
I always have TWO problems simultaneously. All my life. Makes it 10x more difficult to fix something. GRRRR.
Remove the plastic plug on top, replace with a nipple-Tee-Schradder Valve-guage set up so you can pressurize the tube and monitor pressure loss. DO NOT ADD MORE THAN 5 PSI!!!!
If the welder was indeed certified, the only reason he would not have done this would have been laziness.
Each tube will have multiple chambers-everywhere there is a vertical weld there is a baffle creating another chamber-GREAT IDEA BENNINGTON!
regarding small amount of water remaining in tube.....this will evaporate over time through vented plug, but faster with plug removed.