From ArmA3Nimitz.pdf page 9:

Boat Deployment
The Nimitz is equipped with davits to launch and retrieve CRRCs and other boats. This room is located starboard of the ship on the hangar bay level, close to elevator 3. There is a sample boat in the room where you can request a boat for yourself, provided that the davits are not already in operation. Note that the Nimitz boat module needs to be set in the mission and the player needs to be synced with the module.

edit: player can also be synced with one of the top tier modules like nimtz_flightdeck. It just doesn't seem to work for respawned units anymore. Or am i doing sth. wrong?

No, I haven't added respawn to the sync code, it would need to use a respawn event handler. You can add one to your mission via OnPlayerRespawn.sqf script, see https://community.bistudio.com/wiki/Arma_3_Respawn

tyvm, TeTeTe3 ! i got that to work, but forgot to mention it here, sorry ;)