AP requires rudder feedback or VRF (Simrad)?


Dec 21, 2017
Boat Name
Skipjack 24 Fly
How do you know if you need a rudder feedback sensor? I was originally told I did not need one, I was told to use VFR. My setup is a sterndrive bravo one, small bock with a power steering pump; belt driven on the motor. I have a full hydraulic steering ram & helm, EVO3, Nac2, Precision 9 compass and Priority Valve. The solenoids on the valve (there are two, each has two wires) one wire from each solenoid are tied together and to the ground from the nac2 (yellow wire) ,blue wire is not connecter (clutch), the other two wires (one from each solenoid) go to red and black respectively. I used spade connectors so if they needed to be switched I could do it on the water easily but the computer is supposed to figure that out by it's self during commissioning.

Setup\Commissioned the P9 Compass.
During the first part of the dockside (I believe) AP setup it asks you if the drive is moving to the left, it continues to ask you and at some point the drive is supposed to move, mine does not.

Wondering if anyone else has a similar setup, or uses a valve, or just has a clue what dictates the necessity of a rudder feedback sensor. I explained the above to the Simrad tech and he said I needed a rudder feedback sensor but I don't know if he knows shit or not. When I purchased this setup I spoke with a really knowledgeable guy from Simrad and he told me everything I needed for the system and he said I did not need the rudder feedback sensor. It seems to me that the sensor would not keep the drive from being able to move, only keep the computer from knowing where the drive is instead, but I don't know jack.




I Post A Lot But I Can't Edit This
Oct 10, 2010
Los Angeles
Boat Name
We only use VRF on our boat and haven't had issues.

We have an outboard engine with the NAC1, but it should be similar. Basically the VRF would use the compass to make adjustments. If you are moving at a reasonable speed, VRF would be fine. However, you may see it wander slightly at slower troll speeds. You can change the sensitivity and damping values to make it react smoother. Every boat may have slightly different settings.

Make sure your motor is wired correctly and that all your electrical connections are good. Double check the pump voltage rating that it matches your electrical system. It seems like the NAC2 can do 12V or 24V. I'm not familiar with how your solenoids and the valve is set up. It might be the cause for you not getting the power to the motor. Our motor is directly connected to the NAC1 computer similar to the diagram you showed on top. We don't have any solenoids or valves. It would be good to see a picture of what you have.

The key is to commission your VRF properly. This is what you do to commission your VRF. First of all, make sure your data source settings is set to VRF instead of the normal rudder feedback which requires the sensor. Once you start the commissioning process, you do the following:

Part 1:
1) Manually turn the steering wheel to center your rudder or outdrive
2) The next part, it would say "turning" and ask if the outboard is turning to the starboard.
3) However, it usually starts with a lower voltage setting and it would not have enough power to turn the pump
4) You say "No" to the question about the outboard motor turning.
5) At this point, it would use the same voltage and turn the motor to the opposite direction.
6) If you say "No" the second time, the system would increase the voltage and move the motor the opposite direction again. If you select "no", it basically sets one voltage, turn it one direction, and then the opposite. Then it would bump up to the next voltage level and repeats each direction again. If you still say no, it would bump up voltage some more and repeat. This is basically how you "reverse" the motor direction since there is no option to reverse direction on the chart plotter settings.
7) You keep selecting "No" until the motor/outdrive moves at a reasonable speed and it moves to the starboard side. If your motor does not move at all, have someone sit close to the motor when you bump up the voltage. You should hear the motor turn if its wired properly and voltages are correct.
8) Once you see the speed is perfect and the direction is correct, you select "Yes".
9) It will ask you to apply the higher voltage, so you select "Yes"

Part 2:
1) Now it will ask you to turn the rudder to max starboard manually with your steering wheel.
2) It will tell you to press and hold the button on the screen to move the outdrive/motor to the port side.
3) It should move the motor all the way to the opposite side.
4) Keep holding and release when it reaches the end.
5) This is really for the motor to determine the number of rotations to completely travel from one end to the next.

Part 3:
1) This is where the motor tries to return the virtual rudder back to the center position.
2) There is a bug in their code where instead of using the higher voltage, they would use the original voltage level and pump would move very slowly. What you will see is the pump moves slowly and the rudder may not return back to the center (close but not exactly centered). THIS IS OKAY. Even if it doesn't return to center, its calibrated if you see it try to move back. They don't tell you this, but we learned it the hard way. The system will make small adjustments to find center.

Another note: This is not mentioned in the video, but to properly purge your entire system, the voltage has to be high enough that it turns the motor so you can get all the air out. The way you do this is by pressing the left or right button to move the rudder direction. However, there is a problem. The default setting for the voltage is very low, so the motor may not even turn or turn fast enough. You may need to do a VRF first just to increase the voltage to drive the motor. Purge your entire hydraulic system including the motor to get rid of air bubbles. And after you are sure there are no bubbles, you will need to do the VRF commissioning again to make sure its working properly. Its one of those things that is not obvious until you try to purge the air out of the motor and its not even turning. Any major trapped air bubbles would affect your commissioning.

Go to the 24 minute of the video. Simrad is almost the same.
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I Should Upgrade My Account
Sep 12, 2006
San Diego
Boat Name
26 Skipjack "Reel Hard"
When I did the setup I was pulling my hair out.
As said when the outdrive moves this is a good thing. It does not have to move far. Just move.
What made me pull my hair out was the boat would turn starboard but not port. This was fixed when I did the setup while moving.…it was that the turn rate was way too low.
Another thing for different boats and systems you may need to have the engine running.
Good luck.
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Its a known bug since when the implemented it. They make you go through all the voltage levels and during the final portion, they use the original voltage level so that is why it moves slowly. I learned to ignore the part where it "returns to center" because it never does at the lower voltage settings.
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