I’m pretty sure that the rudder sensor on our Raymarine AC400 Evolution Pilot has failed. Certainly the boat goes into increasing oscillations as it attempts to follow a heading and the display does not show the rudder applied. I tested the resistance across the sensor and got the following figures which have little resemblance to what they should be

Red / Green 24.5 ohms (should be 5k)
Red / Blue 1.436k ohms (should be 1.5 to 3.5k depending on helm)
Blue / Green 1.26k ohms (should be 1.5 to 3.5k depending on helm)

I will replace the sensor when I get a chance but my question is: can the AC400 be safely operated WITHOUT a rudder sensor?

Simon

+x

 

Simon Currin - 25 Sep 2021

I’m pretty sure that the rudder sensor on our Raymarine AC400 Evolution Pilot has failed. Certainly the boat goes into increasing oscillations as it attempts to follow a heading and the display does not show the rudder applied. I tested the resistance across the sensor and got the following figures which have little resemblance to what they should be

Red / Green 24.5 ohms (should be 5k)
Red / Blue 1.436k ohms (should be 1.5 to 3.5k depending on helm)
Blue / Green 1.26k ohms (should be 1.5 to 3.5k depending on helm)

I will replace the sensor when I get a chance but my question is: can the AC400 be safely operated WITHOUT a rudder sensor?

Simon

Hi Simon,
I would contact RM.
No real help here unless it is helpful that we have gone 10s of thousands of miles on our autopilot and we have no rudder sensor. Unless you educate me otherwise, my guess as to the purpose of a rudder sensor is to optimize steering accuracy and to minimize amp draw. If that is accurate, then operating without a rudder sensor might just lead to more amp draw and less accuracy: probably not a big deal, especially when motoring.
Let us know what you discover.
Good luck, Dick Stevenson, s/v Alchemy

Thanks Dick that’s useful I will disconnect and see what happens.

+x

 

Dick - 25 Sep 2021

+x

 

Simon Currin - 25 Sep 2021

I’m pretty sure that the rudder sensor on our Raymarine AC400 Evolution Pilot has failed. Certainly the boat goes into increasing oscillations as it attempts to follow a heading and the display does not show the rudder applied. I tested the resistance across the sensor and got the following figures which have little resemblance to what they should be

Red / Green 24.5 ohms (should be 5k)
Red / Blue 1.436k ohms (should be 1.5 to 3.5k depending on helm)
Blue / Green 1.26k ohms (should be 1.5 to 3.5k depending on helm)

I will replace the sensor when I get a chance but my question is: can the AC400 be safely operated WITHOUT a rudder sensor?

Simon

Hi Simon,
I would contact RM.
No real help here unless it is helpful that we have gone 10s of thousands of miles on our autopilot and we have no rudder sensor. Unless you educate me otherwise, my guess as to the purpose of a rudder sensor is to optimize steering accuracy and to minimize amp draw. If that is accurate, then operating without a rudder sensor might just lead to more amp draw and less accuracy: probably not a big deal, especially when motoring.
Let us know what you discover.
Good luck, Dick Stevenson, s/v Alchemy

Dick
I can confirm that the pilot works fine with the rudder reference unit disconnected. I’m just wondering if he $CAN 350 is worth the money?
Simon

+x

 

Simon Currin - 27 Sep 2021

Dick
I can confirm that the pilot works fine with the rudder reference unit disconnected. I’m just wondering if he $CAN 350 is worth the money?
Simon

Hi Simon,
Good knowledge to have.
I am not a big internet user, but I would look for a RM list-serve where that question could be asked. Then there are RM sales people and the like. I have found technical assistance over the phone to often be more forth-coming (even sharing shortcomings) and certainly more knowledgeable about their equipment than sales people or customer assistance people.
I would bet that some disciplined observation on your and Sally’s part over a variety of conditions will tell you whether there is a noticeable difference in performance.
My take on rudder sensors was always been to place a Turk’s head at the top of the wheel when the rudder was amidships and to balance the sails better whenever the Turk’s head was more than a ¼ turn of the wheel off dead straight rudder.
My best, Dick Stevenson, s/v Alchemy