target_engine
target_bow
target_stern
target_rudder
target_drivingseat
Could we perhaps have a func_boat entity, along with some target_ entities to tell the engine where the boat's bow, stern, engine, rudder and drivingseat are?
A func_boat would be a collection of brushes that the mapper decides would make a sterling boat. It could have a keyvalue saying what it's weight is, it's boyancy, and perhaps what it is made of (steel, wood, etc) and what liquids it can float on (water, slime, lava, etc, those not specified it would sink slowly in maybe?)
the func_boat would then target the important things about it.
The target_engine could have a keyvalue pair describing what type of propulsion (wind, jet, propeller, sci-fi beam) and how much horsepower it has. The target stern and bow would basically create a keel direction for the boat, and the target_rudder would decide it's pivot point. The target_drivingseat could be a place that, when a player is occupying that player controls the boat.
Something similar could be done for planes, land vehicles, and spaceships.
This way mappers could make their own player-movers controled by the players themselves.
It would need additions to the compiler ofcourse
.