The flip side of the Navy Shower.
Aboard a ship, and even more so aboard a boat, the importance of conserving fresh water cannot be overstated. It is, in many cases, the limiting reagent in the equations of range, endurance, and stealth of the Navy. All manner of procedures are followed to limit fresh water consumption, but the one that takes its toll on seamen is the Navy Shower. Every day, a quick shot of cold water, some soap, and another shot of cold water. Brrrr! Yes, it wakes you up, but it also takes its toll on your psyche--is Joe Redneck's Constitutional Liberty worth this?
So, to demonstrate that the ship or boat is still connected to America, the Captain is authorized to give out a deliciously satisfying reward: the Marathon shower, or the Hollywood shower. I'll quote from Tom Clancy's excellent text The Hunt for Red October:
Well, he1 did get a Hollywood Shower out of it. Ordinarily a shower on a freshwater-poor ship meant a few seconds of wetting down and a minute or so of lathering, followed by a few more seconds of rinsing the suds off. It got you clean but was not very satisfying. (...) A Hollywood shower is something a sailor starts thinking about after a few days at sea. You leave the water running, a long, continuous stream of wonderfully warm water. Commander Mancuso was given to awarding this sensuous pastime in return for above-average performance. It gave people something tangible to work for. You couldn't spend extra money on a sub, and there was no beer or women.
Amazing how ten minutes of warm water can make you a patriotic citizen again.
1 - "he" is Jonesy, the sonar operator on the USS Dallas.