Why did the H. L. Hunley Sink?
A fragment of copper was found attached to the end of the spar, could the torpedo have exploded while still attached? Objection: there is no evidence of shock impact on the submarine or the men.
Lucky Shot Theory
There was a missing glass plate in the hatch, probably made by a musket ball. The water might have come in and drowned the crew. Objection: there would have been plenty of time for the crew to escape through the other hatch, however this crew were all found sitting at their places, unlike the second crew.
The submarine hit the ship, or another ship, and the submarine was damaged, allowing water to enter in. Objection: there is no evidence of impact or drowning.
The men anchored the submarine waiting for the tide to go out, and died of asphyxiation. Maybe they got stuck on the bottom. Objection: there is no evidence of any unoperational equipment, neither did they release the emergency weights. Also, the men had decided that they didn’t want to die by asphyxiation but by drowning, but the valves to let in the water were not opened.
So what do you think happened… What’s your vote?