Deck.
"Hit the deck" = "Get on the floor" etc.
In the US Navy, the floor is referred to as the "deck".
A Seaman is the correct informal term for a Navy officer. Informal term for a sailor in the US Navy is "bluejacket".
floor
A "standard" hitch in the Navy is 4 years.
Hatch
stacked from floor to ceiling
Filibuster is the term for blocking a bill for holding the floor.
He used a navy ship to sound the sea floor. He found out magma was coming out of the mantle and into the sea floor.
I haven't heard that term when relating to the US Navy. But in the Royal Navy SDG is a scubadiver
The main floor of the Coliseum in Rome consisted of a wooden floor covered with sand. The term arena refers to the sand that covered the floor.
A "mess deck" or "galley" is a common term used in the navy to refer to a break area where sailors can relax and eat.
Nothing - Department of the Navy is the formal title for the Pentagon division that encompasses the U.S. Navy and the U.S. Marine Corps. Navy Department is an informal term.