The phrase "deputy captain" is correct and usable in written English.
It can be used to refer to a person who serves as a second-in-command to the captain, often in a military, sports, or organizational context.
Example: "The deputy captain was responsible for leading the team during the captain's absence."
Alternatives: "assistant captain" or "vice captain."
Listening in on our conversation was another uniformed gentleman, Deputy Captain Seiji.
With the Captain were Air Wing Commander Jeff Davis — the Captain's equivalent, in charge of the planes and the fliers in the same way that the Captain was in charge of the ship and the sailors — and Davis's deputy, Captain Dan Dwyer.
With the Captain were Air Wing Commander Jeff Davis the Captain's equivalent, in charge of the planes and the fliers in the same way that the Captain was in charge of the ship and the sailors and Davis's deputy, Captain Dan Dwyer.
Later that afternoon, at exactly 4 53, 20 guests marveling at a family of humpback whales swimming and spewing just 100 feet from my deck raised a glass or a crab claw to toast the excellent work of Officer Takeshi, Deputy Captain Seiji and Butler Cetin.
The Atomic Energy Commission's Director of Military Applications, Brigadier General James McCormack and his deputy, Captain James S. Russell, met with Bradbury and John Manley at Los Alamos on 9 July to make arrangements for the tests.
When it was over, Major Rong's young deputy, Captain Song, sought us out.
Mr Wilde was deputy to Captain EJ Smith and died in the disaster.
"That this happened in 1996 and he's moved up from sergeant to lieutenant to captain to deputy inspector.
On Sunday, Bo and his former deputy, Wang Lijun, police captain of Chongqing, offered conflicting accounts of a confrontation between the two on 29 January 2012, after Bo was informed of the murder.
The demotion came less than three weeks after Mr. Kerik elevated the commander to the rank of deputy inspector from captain, a rank he had held for less than a year, officials said.
The role made him deputy to Group Captain Caldwell, the wing's commanding officer.
