Explosions can occur on boats from fuel Vapors, particularly propane vapor. Of course any boat would have sensors to detect the presence of such Vapors and would trigger alarms. But propane in particular is heavier than air and can accumulate in the lowest part of the hull for any length of time, to reach an explosive level. It is exceptionally implausible that such a thing might have happened, given that there are sensors, alarms and routine venting of these areas. But these accidents occur often under unbelievable conditions. I had a roommate who used to go out on those boats all the time, complete diving fanatic.
Cited within the last two years for detection equipment issue.