During the last 19 years I have replaced the gears and motor
in my Autohelm/Raymarine Type 1 (now Type 2) Linear Drive
. It is cheap
However, there are several things you need to check:
1) Measure the hard over time on the Linear Drive (LD) arm while it is DISCONNECTED from the rudder. I think it is supposed to be 4.5 seconds from center to hard over but you can look that number up. Then hook the arm back to the rudder and test again. The time should not change.
2) Check the voltage to the LD motor
AT the motor while under load. Put the rudder hard over one way then use the Autopilot to drive the motor / rudder all the way the other way and note the voltage - does it drop - does it stay at battery
Over the years I had to reseat the power and clutch
wires at the course computer several times. The older Raymarine connectors at the course computer are not very good and weaken over time.
3) Use a clamp-on amp meter to test the current
flow to the LD motor while doing a hard over test. Is it 15 amps (Type 1) or 30 amps (Type 2)?
4) Check the clutch
in the LD - you need to be careful here because the drive units are quite powerful. Can you stop the LD from moving the rudder by holding the wheel. Gently increase the resistance and see if you can cause the clutch to slip. The clutch is a magnetic unit and requires good voltage.
6) Check the settings in the control head
- hardover time
- maximum rudder angle
It could be that you have told the LD to respond slowly or not far enough
7) Verify the heading display is accurate on all headings and changes rapidly as you rotate the boat about the compass
8) Verify the rudder angle is properly displayed, reflects the actual state of the rudder, and moves as the rudder moves
We sailed and motored over 12,000 miles with our Linerar Drive Type 1 (15 amp motor) in a cruiser that weighted 23,000 pounds in local sailing trim and 26,000+ pounds when in cruising trip. The LD happily and easily managed the boat downwind in 35 knots and 12' seas many times. A Type 1 has plenty of power for 22,000 pounds.