A marine mammal that lives in the engine room of every US submarine. NUBs are sent to feed them for the pleasure of more senior sailors.
"Hey NUB, go feed the shaft seals."

"But the shaft seals are actually a series of interlocks and safety mechanisms that ensure the integrity surrounding the ships main propulsion shaft, and not nautical mammals; but I'll go feed em if you want."
by B H T July 18, 2008
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