An autopilot controls the steering gear of a vessel to keep it on course. There are two types of control methods. One is called single-loop control and uses torque motors or the like, and the other is called two-loop control which uses solenoid valves or servo-cylinders as actuators. The actuator selection depends on what type of steering gear is used.
PT500: This type is widely applicable to many types of vessels and can be easily adapted to any type of steering gears and actuators.
PT70: This type is suitable to middle size and small vessels which use solenoid valves. It is designed for easy mounting on the consoles of small vessels.