The name would be USS Plunger (United States Ship).
I'm not sure it's fitting because it brings thoughts of cleaning a toilet. A plunger is a plumber's tool.
However if plunger is used as one who bets, think gamester, then there are better synonyms for that which make it a more fitting name.
Risk-taker, high-stakes bettor... However I am certain the U.S. Navy would "wager" that "all bets are off" when it comes to the power & capability of a submarine!
