To conn means to control or direct by rudder and engine order telegraph, the moments of a ship.
- That’s from U.S. Navy’s Watch Officer’s Guide Ninth Edition. (1965, I bought it used some time ago)
Also:
(a) One and only one person can give orders to the wheel and to the engine order telegraph at one time.
(b) The identity of the person giving the orders must be known to the personnel on the bridge.
(c ) The Officer of the Deck may be relieved of the conn by another officer, but retains a considerable measure of responsibility for the ship’s safety.
The book mentions that the OOD watches that the conning officer’s orders are carried out and otherwise acts as lookout.
It goes on for a couple pages, it uses the term "two-intellect system, where one officer conns and the other monitors.