Most automatic cars that can be towed in a horizontal position are designed to be towed in neutral and with the steering wheel unlocked. However, before towing a vehicle by boat, you should consult the owner's manual or the vehicle manufacturer for appropriate settings and procedures. If the vehicle is mounted on a rolling platform, put it in first gear and tow it. If all four wheels are on the ground, place the vehicle in neutral and tow.
Vehicles with manual transmissions can generally be towed without the car running, without the risk of damaging the transmission. Or, if you prefer, Demco and Roadmaster offer adapters that allow their tow bars to fit a Blue Ox motherboard, and boat braking systems (especially portable models) can work on any towed vehicle. The main reason why vehicles cannot be towed is that the transmission is not lubricated unless the engine is running, which will cause overheating and could even burn out when towing a boat.
