Last summer after finding and fixing the leaks, I reduced the weight of my ancient sunfish from about 185 pounds to 130 pounds without installing inspection ports. The boat had a small drain hole in the transom as well as the standard small drain hole on the starboard side of the deck. I taped a very small 12 volt fan (designed for a computer) tightly to the deck so it would blow air down the starboard deck drain, and powered the fan with a small solar panel. After 2 weeks under its canvas-like cover and on its trailer in the hot sun (average high temperature here in Texas was about 100 degrees) the boat was reduced from 185 to 152, and after the fourth week it was down to 130 pounds.
During the hottest part of a sunny day, the air exhausting the transom hole was obviously warmer than the ambient temperature and more moist than the average humidity of the summer air. It could fog up a clear glass held near the exhaust hole. But by the end of the 4th week, the outflowing air was merely still warmer, but not more moist than the ambient air. The absense of the excess moisture signaled that the hull had finished drying.
The air movement was gentle, not fast; but it was consistent throughout daylight hours as the sun powered the fan through the solar panel.
During the hottest part of a sunny day, the air exhausting the transom hole was obviously warmer than the ambient temperature and more moist than the average humidity of the summer air. It could fog up a clear glass held near the exhaust hole. But by the end of the 4th week, the outflowing air was merely still warmer, but not more moist than the ambient air. The absense of the excess moisture signaled that the hull had finished drying.
The air movement was gentle, not fast; but it was consistent throughout daylight hours as the sun powered the fan through the solar panel.