Clever - but if you are going to synchronise the turrets to all point at one target, how do you designate the coordinates of the fixed target point to a moving boat?
Thinking of typical ranges of the time as 8000yds and up, at the scale I'm working at, the minimum distance to target would be about 110yds. All turrets would effectively be parallel.
A scaled 20 knots is about 'walking pace', say 10 feet per second. At 110 yards the change in angle of a target, at maximum, is only a degree a second or so. When on parallel/near-parallel courses (like most of the actions in WW1) the angular change is minimal.
To effect a turret rotation as the target changes bearing is automatic during a turn by the turret-carrying vessel, and would require a simple 'new target heading' and 'set' transmission in the system I'm developing.
IDEALLY, all prospective targets (!) should mount an IR-LED on their masts. There are chips available that can read signals from such LEDs. The work of scanning the horizon for a target wouldn't be impossible using Arduinos/other processors. ...Which, I suppose, would be a game changer for those who are determined to sink boats with gas-powered bbs.
Andy