It’s not. It is prop and steering.
I also reduced the motor size reduced so max speed about 2m/s. No sure if that could be effecting it?
Your ATC_STR_RAT parameters are not tuned at all.
Sorry David, I’m not sure what these are? Will look them up now. Thank you for the help.
Hi, i had a same problem with my boat, in auto mode, she swam in zigzags.
Spent quite a lot of time to adjust the parameters (about 10 hours). Not I’d say that with all were worked out, but boat now swims adequately (https://youtu.be/1IywUuRiJfs). Full list parameter’ll attach!
Accurately remember, that first got hooked for parameter STEER2SRV_IMAX, under his increase controller is beginning to more aggressively steer and try to keep course, in further reduced significance this of the parameter, that would governance was more smooth.
The next parameter NAVL1_PERIOD, a low value leads to a low level of response to a control error, a large value causes the course to return aggressively, i stopped at the value of 25 seconds.
And third this PID’s, STEER2SRV_D as me it looked not gives nor what good, only makes the boat more nervous in managing. So I set 0.
STEER2SRV_P large values lead to overshoot, small to understeer, just need to pick up. I was approached 0.4.
And the last output parameter STEER2SRV_I, it greatly affects the zigzags, I set to 0 and then gradually added. While the value is too small the boat can not keep the course as soon as it starts to stay the course, add a little more. Larger values immediately lead to overshot and zigzags.
I use APM 2.6 with firmware rover 3.4.2
boat.param (4.6 KB)
A couple of things. STEER2SRV_FF is 0. That’s no good. Also cruise throttle is more than throttle max. I did not think 3.4.2 was good for an APM 2.6
Small values of STEER2SRV_FF (<1) did not give any result, large values led to zigzags.
“Also cruise throttle is more than throttle max” - agree, on fact he swims with throttle max.
“I did not think 3.4.2 was good for an APM 2.6.” - what’s good? As I understand it further APM support is discontinued and this is the last available version?
2.5.1 is the last for APM 2.6. STEER2SRV_FF will most likely be >1. Then the NAVL1 is turned up to mellow out the zig zag after the STEER2SRV P,I, and FF are set reasonably well.
Thanks, I will try to continue to configure!
3.4.2 seems to be working!
I plan to upgrade to omnibus f4, to use the latest rover firmware.
Omnibus would work well with the latest versions of the firmware?
I don’t know. I’m still using genuine 3DR Pixhawk 1’s.
You don’t have Rover 3.4.2 on that APM 2.6. That parameter file you posted is missing about 380 parameters for it to be that Rev. And of course it’s simply not supported and can’t be flashed. What happens is if you select a firmware version the board won’t support it will flash the last one that does support it. Post an actual .bin file log and we will know for sure.
I’m sure the Omnibus F4 will work fine. I use an Omni F4 Nano on a Multirotor and it works great.
on how many I remember, I’m using here is this firmware: http://firmware.ardupilot.org/Rover/stable-3.4.2/apm2/
And what does the firmware-version.txt file say it is in that link?
Just look at the top status bar in Mission Planner after connecting and it will likely say 2.5.1 or a beta of that…
Now everything is clear! Thank you!
Hello friends, can you share boat configurations. I’m a new and hope your experience will help me set up my boat.
My configurations is simple 1 motor 1 servo
And my problem is:
When i put RTH and auto mode the boat move zigzag
In this post, a file with parameters is attached! 
You need the parameter NAVL1_PERIOD here is his description: This controls the aggressiveness of the navigation algorithm. A smaller number means more aggressive turning in AUTO mode, a large number means larger, smoother turns.
If the boat is zigzagging, increase this parameter!
Thanks ,i will test it on my boat !