Linear drive/hydraulic packages now come in a single
unit with a ram to attach to your quadrant or tiller and a built in hydraulic pump and reservoir all in one unit. You hook up your DC feed wires to the unit and the motor
drives the hydraulic ram that pushes/pulls on the rudder
quadrant/tiller. There are many versions built by many of the major autopilot
companies. And you can normally mix and match the various units with various autopilot computers
- - Autopilots now come with a whole menu of fancy features most of which you will never use more than once. What you do use most often is the compass
heading mode which simply holds the boat on a heading you select. For this feature to be best utilized you need a "rate gyro fluxgate" rather than a simple "fluxgate". Fluxgates are solid state without an internal "floating compass". As you start a turn to a new heading every fluxgate/wet compass
will start to turn in the opposite direction. The rate gyro fluxgate
senses this and prevents the heading information from feeding this "opposite direction" information to the autopilot computer. That's the theory, anyway.
- - The feature that hooks into your wind
direction instruments is worse than useless in most cases. The little wind
direction vane at the top of the mast
is normally swinging and moving all over the place due to wind variations and mast
swings. If you want constant wind angle sailing buy a real windvane
for your transom.
- - The "navigation" feature is nice but can really get you in trouble as it will steer the boat according to the route
information you have entered in your navigation
system computer. The autopilot will attempt to constantly keep you on your plotted course line which with moderate seas and varying wind will result in constant autopilot "grinding" to turn the boat. But the big "brown you pants" moment with the GPS navigation
mode occurs when you have entered double waypoints on top of each other. At the waypoint the autopilot will attempt to turn to the hidden waypoint usually resulting in a 180 degree turn just when you don't expect it. Talk about a Mexican circus as sails
, booms and crew dash about trying to figure out what is happening. If you are entering a harbor when this happens, it really gets exciting/terrifying. It takes supreme discipline and carefully route
entry procedures to prevent this.
- - So you end up with the "compass mode" being the most used. Try to find a reputable unit with solid history
of "just working" and has a good "rate gyro" fluxgate
option. I use the Simrad
Robertson series units primarily because of their reputation as solid, just keep working, units.