Navpilot 300 Settings

[Helmsman]

I have a Navpilot 300, an SCX20, and a TZT3 chart plotter. In looking through the settings, it shows 12 mph for the cruising speed of the boat. The boat is a 41 foot trawler that cruises at 7 to 8 mph with a top speed of 14 mph. Should the cruising speed in the settings be set closer to 7 to 8 mph?

When navigating a route, the trawler tends to weave off of the line in one direction and then correct past the route line in the other direction. It is like it is hunting for the correct heading. This happens every time, whether heading into current, running with current, and in different wind conditions. I would like the trawler to run more tightly to the navigation line. What do I need to do to achieve that. Rudder indicator is tight and aligned correctly, the AP computer is about 20 feet forward of the rudder, ram, and pump. The self learning setting is on.

 

[Johnny Electron]

The Navpilot 300 isn't really designed for a trawler. The Navpilot 711C or Navpilot 1000 should have been used depending on the steering system. You definitely should put in the real cruising speed. Did they at least put on an inboard rudder reference unit? What is the hard over time it takes to go from stop to stop using the dodge buttons? Any self learning is done in the first 5 mins so whatever you have going on isn't going to get better with that.

 

[Helmsman]

Thank you. I will change the speed. Here is the forum post where I asked about which AP to purchase.

H

Thread 'Which to buy 711c or 300?'

Sep 13, 2021

New install on a 31,000 lb Helmsman 38E Trawler with a single engine, and two helms. The boat is full NMEA 2000. Would like to use the SafeHelm2. I haven't been able to successfully distinguish the difference between the two AP's. Any suggestion as to which is the "best" for that type of boat?

• Helmsman
• Replies: 20
• Forum: Autopilots

I also called your technical folks and discussed which I should use before I purchased and installed the 300 to determine whether I should use the 711 or the 300. I was told that the the 300 was ok for our 41 foot 31,000 lb trawler. I installed an inboard rudder reference unit which is aligned and working properly.

Most of this manufacturers boats are set up with a Garmin package. If I remember correctly, and I specifically asked the PNW installer, the pump size (Oct 16-12) I picked was the same as the Garmin installs.

At any rate, this is what I have installed. In looking through section 4.1.1 of the manual, it talks about setting the deviation level, and then in 4.1.2 it discusses setting the rudder gain and counter rudder. Should I consider altering any of these three, and if so, to what degree would you recommend changing them to? I certainly don’t want to over tax the pump, or “over work” the rudder. The issue is more of a noticed issue, not a safety issue. Really just a little annoying.

Thanks again for any help you can give, and I certainly realize that this is a judgement I alone need to make. I just want to have your thoughts on what might work best before making that judgement call. Thanks again for all the help you guys have provided over the past few years. Your service levels are outstanding!

 

[Helmsman]

I have also read somewhere in the past few days that the AP zigzags less using SOG versus STW. The PGN’s are both showing up in the AP list of PGN’s. Is there a setting on the AP to use one versus the other, and do you have any thoughts on it?

 

[Johnny Electron]

With the SCX20, it is clearly not a heading issue.

Two standing questions:
1) Do you have an inboard rudder reference unit installed?
2) What is the time it takes to go hard over to hard over using the dodge buttons?

 

[Helmsman]

With the SCX20, it is clearly not a heading issue.

Two standing questions:
1) Do you have an inboard rudder reference unit installed?
2) What is the time it takes to go hard over to hard over using the dodge buttons?

1) Yes
2) From port hard over to Starboard hard over using the dodge button, it takes 7.5 seconds.
The rudder will turn 30 degrees in each direction via the helm. The autopilot is set for 25 degrees in each direction.

 

[Johnny Electron]

Hard over time is a bit fast but should be fine. When was the last time the rudder test was ran in the water and the seatrail "set center" done?

 

[Helmsman]

Thanks Johnny. Both were completed in the spring of 2023.

If it helps to fill in the blanks, I have a friend with the same boat who also has the same equipment. His was commissioned at the same time. I had my install done at Aqua Yacht in Iuka ms. His install and commissioning was completed at the same time by BOE Marine in Kent Island Md. We both are experiencing the same issue. That issue has been with us both since then.

 

[Johnny Electron]

As the start of the original thread the NP300 is designed with focus on center consoles and outboards. The RRU setup, Rudder test (in the water) and Seatrial set center are the key if the heading and Hydraulics are good. I would recommend ensuring the help is turned hard over correctly during the RRU setup and run the rudder test and see the posted results to that. After the seatrail, (and setting center) see if there is improvement. If that doesn't work, get with tech support and they can give you a file to add to a USB stick that can be put into your processor to collect data and be sent to the parent company for analysis. I would understand things better if the NP711C was used but it could be air in the hydraulics bad check valve, or just using a pilot that really isn't designed specifically for a boat like this. One step at a time. Let me know what the rudder test results show on screen after reset of the RRU.

 

[Helmsman]

Thank you, Johnny. It may be a a few weeks before I can get to it, but will report the results back when I do. As always, I appreciate your help.