Hunter 37.5 Autohelm Rudder position Sensor

[BUD11290]

We have a ST4000+ Autohelm on our 1991 37.5 and have been advised by Raymarine to install a rudder position sensor. Has anyone installed one of these sensors, if so I would like to discuss installation details and how well it performed.Bud

 

[Frank7609]

Straight and Steady

Bud, After 6 years of passable but not great ST4000 performance, I installed a rudder reference transducer on my Hunter 30 this spring. It made a new machine out of it. The boat now tracks much better under sail and there is not as much drive activity which translates into less wear and tear and less electricity. If I knew then what I know now the rudder reference would have gone on with the initial installation. If your rudder set up is similar to mine (88 model) then the unit just mounts in the well next to the quadrant and attaches to the quadrant with the supplied hardware and little homemade aluminum angle bracket. Run the cable to the autopilot control unit.

 

[BUD11290]

Rudder Position Sensor Photos

Thanks for your reply on my question regarding Autohelm Rudder Position Sensors. I am encouraged by your positive comments. Would you have a photo or sketch of your installation?Bud

 

[Frank7609]

No big Deal

Bud I do not have a picture, but maybe a little verbage will suffice. The rudder position sensor is just a potentiometer (volume control) in a housing with an arm that connects to the shaft. If you will look at the pictures of the unit you will see that it mounts by a few screws on the flange on the base. To connect the arm to the steering system the unit is supplied with a length of threaded rod and a couple of fittings for each end. One end of the rod goes to the sensor arm and the other goes to the rudder shaft so that as the rudder turns the sensor also turns. I connected mine to the steering quadrant on the rudder shaft. I used one of the small bolts that holds the two quadrant halfs together to attach a small aluminum angle backet. To this angle bracket I attached the other end of the all thread rod connector. In my case the vertical heights were close enough that I did not need any blocks under the sensor for it to line up. In your bigger boat you might need some extra height to get the vertical alignment right. The position sensor is set up so that when the rudder is amidships the sensor arm is in the middle of its travel. If you do not get it exact then you can adjust the threaded rod or the elongated mounting holes. There is also a software adjustment in the 4000 control head. The 4000 control head automatically senses that a rudder sensor is connected and starts using that information and will also indicate the rudder position on the bar display on the bottom. You will have to readjust the gains ect but that is no different than on a new installation. It is really no big deal and it will make a big difference in the operation.