Right tune for tacking.

[ArjenR]

L.S.

My boat is relatively light and steering is very direct and sensitive. I am using the PCNautic tiller drive which is tinypilot based if I am correct.

The issue I am having is that the tack is fast enough heading into the wind, but once in the middle of the tack. With head to wind, the autopilot is already slowing the tack down and tries to ease too early and too much into the new tack. Which means the boat stays too long head to wind and head to waves and bogs down almost to a stop.

apparent wind is from 30deg/ true from 40deg (app.)

parameters used:
ap.tack.angle 80 deg
ap.tack.delay 2sec
ap.tack.rate 100%
ap.tack.threshold 100%

If I am correct the tack threshold should tack the boat in one go to the new heading. But this is not what I am observing.
All other tuning parameters I am using are in the picture.

What could I try to get a proper tack?

   

[seandepagnier]

You said PCNautic tiller drive. Is this just the drive or the electronics as well? The pcnautic electronics and software was forked in 2021 and from what I recall has different tacking logic unless they have merged.

I much more recently improved tacking (2023) in master pypilot so it is hard to say what you are running.

A few things that seem strange
servo.period 0.1 This is very low. Can you try .2 .3? Might not affect tacking but it is strange.
servo.speed.min 5% Also quite low, Try at least 50-60%?


Having the threshold at 100% should keep tacking until you hit the new target. Where a threshold of 50% would stop tacking when facing the wind, and simply try to follow the new heading which often works because the boat is already turning fast at that point, and helps to avoid overshooting the tack. I even used a threshold of 40% on my boat. With 100%, the rudder should go hard over and stay there and actually overshoot the tack every time so this is strange, but it seems unlikely you are running my latest changes anyway.

As for rudder range, how far can the actuator actually move the rudder? For good tacking it needs more range than general course keeping, but tacking is hard. Tacking with waves is different from calm, tacking in high wind different from light. Tacking with one sail different from two, and so forth, and by different I mean completely different timing and parameters depending on the boat, for example with just a mainsail, in high winds, my boat stops dead into the wind, and I have to reverse rudder as the boat starts going backwards to get it on the right tack. The autopilot does not understand steering backwards yet.

[ArjenR]

Thank you for replying.

So it is the pcnautic drive and controller. I think it uses a more recent version since I recall reading the improvements in 2023 introduced the threshold parameters amongst others?

Angle of the drive is 25% and this is enough for my boat. As I wrote it sensitive to the rudder and also wind gusts etc. The servo parameters are default for this system and suit me fine since the response in gusts is quite on point.

But you mentioned that it should go full on tacking until the pilot sees the same apparent angle on the other tack?
If that does not happen it is probably an older version. I have reported this to support of PCNautic but it is the summer holidays here so their response will be delayed.

Regrds Arjen

[seandepagnier]

Yes, if you have used their diverged software it is difficult for me to support.