Navpilot 300 Won't Hold a Course. Please Help.

[calla969]

I have a fairly new NavPilot 300 installation. It has a SCX-20 for the heading sensor and it's paired with a TZT3 plotter. There is also a Safe Helm 2 installed and I'm using an Octopus pump (PUMPOCT10-12). The boat is a 25' center console with a single 250 outboard using the phantom feedback.

When I first installed the system, it worked beautifully. A while ago when I was offshore it would not hold a course. It would wander all over the place and veer quite far from the track. It would start giving me alarms for being too far off course, but would not correct. I would have to disengage the autopilot and correct manually, only to have it do the same thing again once I reengaged the autopilot. I noticed today that if I put the AP in course hold, the blue line that appears on the chart plotter showing the AP course does not align with the red dashed heading line. There was no current and a light wind at my back. The two lines never come into alignment. I am using precision mode and when holding a heading, I am using the Advanced mode. I did a little research and heard that it may be due to trim tabs being deployed unevenly in a rough sea and it was having a hard time correcting. I recently did some major refitting on my boat which involved replacing the trim tab cylinders and also rebleeding the steering system. Just today, I did a test run after the work was finally complete. It was a 3 month project. Today while running the boat in the intracoastal in very calm water, I experienced the same thing. The boat wanders all over the place and once even made a pretty abrupt turn in the opposite direction of what was required to correct the direction. It seems pretty good at a fast idle speed, but on plane, it is completely useless and I would even say dangerous with that severe turn it initiated. Does anyone have any suggestions on what I should do to troubleshoot? The boat is on a trailer, so it's kind of a lot of work to test it and I have a long distance trip coming up and I was really hoping to be able to use the autopilot during that trip. I will probably only have one chance to get the boat in the water before then. If I can't get this resolved, I will not be able to use the autopilot which will be very disappointing. I would really appreciate some help. Hopefully there is a simple solution.

 

[calla969]

I was just going through all of the settings in the AP to see if anything looked off. In the Sea Trial menu, there was nothing selected as the compass. I selected the SCX-20, and saved. Could that be my issue? The SCX-20 was selected in other screens and I don't get any error messages or alarms. Not sure how it would have changed.

Based on other threads I've read, here's some additional information:
Hard over to hard over is 12 seconds.
The Dockside Setup was performed with the boat on the trailer, not in the water.
Rudder Drive was set at 2. I do feel like the pump was not running enough to make corrections. Should this be increased?

The Sensors Selection menu looks as follows:
HDG - SCX-20
STW - TZT12F
SOG - SCX-20
POSN - SCX-20

 

[Johnny Electron]

The rudder test and hard over timing must be done while the boat is in the water. I had a similar result when I configured the dockside on the boat on the trailer and didn't set it up while in the water. The trim tabs and other items might have started your grief but I think you should be alright if you dockside the boat in the water (min rudder test) and then seatrial the "Set Center" with the trim tabs out of the picture. The pilot sets everything up during the dockside test so that should be redone in the water. If you have an SCX20 for heading, I have no concerns there. Ensure that your speed source is setup for SOG and not STW. STW can be problematic as speed thru water sensors tend to foul. First glance, I think you will be up and running well with a bit of proper setup.

 

[calla969]

The rudder test and hard over timing must be done while the boat is in the water. I had a similar result when I configured the dockside on the boat on the trailer and didn't set it up while in the water. The trim tabs and other items might have started your grief but I think you should be alright if you dockside the boat in the water (min rudder test) and then seatrial the "Set Center" with the trim tabs out of the picture. The pilot sets everything up during the dockside test so that should be redone in the water. If you have an SCX20 for heading, I have no concerns there. Ensure that your speed source is setup for SOG and not STW. STW can be problematic as speed thru water sensors tend to foul. First glance, I think you will be up and running well with a bit of proper setup.

Thanks, I'll redo the Dockside setup next time I get the boat in the water. I don't have a STW sensor in the network, so whatever the AP is seeing for STW should be coming from the TZT3 which would just be GPS speed, right? Should I just set STW to none instead of the TZT3?
My Rudder Drive Level was set to 2. Should I change that setting? What is recommended, not exactly sure what it does.
How about Deviation Level? It was set at 8 and I changed it to Auto.
Also Speed Calculation. It's currently set to Auto. Is that OK?
In the Sea Trial menu, STW Adjust is at 100%. Should I change it?
Also in the Sea Trial menu, under Compass Setup there was nothing listed. I selected the SCX-20 there, but next time I turned the unit on it was blank again.
Sorry for all the questions. I'm going to be taking this trip in a few weeks and will only have one more opportunity to put the boat in the water before then if I'm lucky, so I want my best shot at getting this resolved.

Your help is MUCH appreciated!

 

[Johnny Electron]

If you don't have STW, it is okay to leave it set to the TZT3 but it will never get data that doesn't exist. I normally just leave the STW selection empty when you don't have it. By the sound of it you would benefit to just factory reset it and start over. On a console boat most of the settings are AUTO or left at default. You don't setup a SAT compass like you do a Flux gate. There is nothing you need to setup on a SAT compass in regards to calibration. You only need to select it properly as your heading source. In the water the hard over time should should be between 7 to 13 seconds.