If the President is on a Boat/Ship...

Factual Questions
1

Is there a special name for it? I understand the Air Force One and Marine One thing. Is there a Navy One?

2

These radio call signs apply primarily to aircraft. However, when the President is aboard a Navy ship, it becomes Navy One. There was a Presidential Summit at Malta in 1989. The USS Belknap became Navy One for several days.

Air Force One
Marine One
Navy One
Executive One (if the President is on a private aircraft)

3

…and if he’s just walking, it’s Army One. Obviously.

4

What about the Coast Guard?

BTW, this is one of the goofs from Independence Day. The President flies a fighter jet and is referred to as Eagle 1. His call sign should have been Air Force One (probably the most maneuverable One ever…).

5

I doubt that it would be considered prudent to give a special call sign to the fighter jet being flown by the President in combat-talk about creating a primary target. (Not that it was particularly prudent for him to be flying a fighter jet in combat in any case, of course.)

6

I posted a similar question a few months back.

Apparently, whenever the Prez hops into a limo or a Suburban, that vehichle becomes Army One.
(BTW, the licence plate on the Presidential Cadillac Limo
is USA-1, or USA-ONE, one or the other).

7

Whenever Reagan used to go riding on his ranch, his mount had the codename Horse One.

Okay, I made that one up.