Learn English – Analogy for arising difficulties

On its face, I take the underlying meaning of this quip to be "If lightning bolts struck people down according to their deserts, they would target more of the world's idiots".

(I suspect that most of us have some sympathy for this sentiment.)

A hose pipe would be connected to a bilge pump to allow sea water to be removed from the bilges of a ship and ejected into the sea. Since ships' hulls were (and still are) not water-tight, this had to be done regularly, and was an arduous task in the days of manual pumps.

Drunken sailors were sometimes hosed-down with bilge water as a form of punishment. The sailor would simply be placed, face up, by the scuppers (where the water would drain off the deck immediately) and given a thorough soaking. It was far less dangerous than keel-hauling and much less painful than flogging, although there was possibly a risk of drowning, either on the bilge water or the sailor's own vomit. Perhaps we should consider it to be an early form of waterboarding.

P.S. Since I can find no reference to the custom as a form of punishment, it may simply have been used as a way of bringing a sailor out of a drunken stupor. The real punishment (if any) would come later. On merchant ships, it would probably have been a fine.

Royal Navy & Marine Customs and Traditions

BBC: What did they do with the drunken sailor?