Raypilot 650 and Raytheon Rudder Angle Sensor

[GMB]

The Autopilot on a friends boat was not behaving recently and caused us to have to hand steer from Savannah, GA to Melbourne FL. Notable observations:
1) The Raypilot 650 would begin a heading hold mode but after wandering a few degrees from commanded heading the unit would throw a "Drive cut" fault.
2) Raytheon rudder angle sensor seemed installed correctly with in-tolerance parallelogram linkage and wiring exiting base aft as illustrated in the documentation. However, upon calibration, the angle indication for an actual midship rudder was 27 degrees to port. This was confirmed through the Raypilot 650 display of rudder angle during manual lock to lock exercise with indication of 64 deg port (full port) to 10 deg starboard (full starboard). The sensor housing seems intact with the original plastic base rivets intact

Once we are able to access the pump we will check power connections and monitor voltage at the hydraulic pump for a drop while repeating the functional check.


My questions to the group are:
1) Has anyone seen this type of skewed indication from a Raytheon rudder sensor and remedied it.
2) Could the apparent "Drive cut" events be related to the rudder sensor issue or is it unrelated.


Thanks for any input.

 

[Jeff F]

I suspect they're related. I'm not intimately familiar with the 650 but I'd bet that there is a step in the commissioning process where you zero the indicator. It should be in the installation manual, which is available online.

It's not a bad excercise to go through the new installation setup step by step, and it often will solve problems like this.

 

[GMB]

Before arriving I had collected all available manuals. The first thing I did was step through the post installation setup. That's how I discovered the rudder sensor bias. There is a data entry step to correct for sensor error but the parameter range is only -7 to +7 degrees.

 

[Jeff F]

You're one step ahead of me!

The sending unit should have reference indicator bars that line up at zero degrees. If you can see them it's easy to confirm that the base orientation is correct, or is 27 degrees off as reported.

It's possible the two issues may not be connected, but I'd want the rudder indicator to be correct. It's a key component in the system.

I'm sure others can chime in on testing the indicator with a meter.

 

[Solly]

Center the rudder using the wheel. Half the 'lock to lock' turns. At the rudder confirm the rudder and rudder bar is centered. Check the stops. Disconnect the rudder angle indicator and see if it is centered in it's travel. If it is it's probably bad. If not, adjust, with the threaded adjustment or turn the base, until it is close to mid point then use the setup program on the head unit to get it on.
If it's bad or out of adjustment it will be sending a false rudder position to the autopilot and the pilot will be commanding a change of position to the rudder to get to the set heading. If the heading doesn't change it probably thinks the pump is not working correctly.