Final answer:
In the story possibly referenced as "Take Over, Bos'n!" but likely meant to be "The Open Boat" by Stephen Crane, there were four men in a lifeboat. The ship's name is not given, and the excerpt does not mention anyone guarding water with a gun.
Step-by-step explanation:
In the story "Take Over, Bos'n!" which appears to be a misquoted title potentially referring to Stephen Crane's "The Open Boat," there were four men in a lifeboat. The actual name of the ship that crashed is not mentioned within the quoted text. The excerpt does not provide information about someone guarding the last supply of water with a gun, so it is not possible to give a confident answer to that part of the question. In "The Open Boat," the men work together to survive after their ship, the SS Commodore, sank off the coast of Florida.