ST 4000+ recipe Catalina COCKTAIL

[Mick Laver]

We recently did a 60+ nm passage with substantial following seas. We gave up on the autopilot fairly quickly. When we got back I searched this list and found a thread started back in Oct 2001 about tweaking some of the settings to make the ST4000 behave. I've made the changes and will test them out on the same passage this weekend (without the same sea state, I suspect), but I'm curious if anyone has come up with anything better in the last 14 years. Here's the changes:

Rudder Gain:    Old 3, New 2
Response:        Old 1, New 2
Autotrim:         Old 3, New 2
Drive type:       Old 1, New 2
Rudder damp:   Old 2, New 4

Thanks all.

[Stu Jackson]

Mike,

That's called the Catalina Cocktail and it modifies the settings for a smoother ap operation.

Here's why ap's don't always work going downwind (although newer and stronger below-decks unit's do because they are stronger)

http://www.c34.org/faq-pages/faq-autohelmwacky.html

[Stu Jackson]

Mick,

Just another idea that I've used:  You CAN change the gain, response and damp while you're sailing.

I keep the ap in a "quick" mode when motoring and sometimes when going upwind (although the boat will sail itself upwind WITHOUT the ap with proper sail balance and trim) and then I change some of these features/parameters when going downwind to deliberately slow the ap down.

The SLOWER the ap works when going downwind or with quartering seas, the more stable a ride.  Just like (almost) if a person was driving downwind, i.e., hardly moving the wheel while the boat tries to wander.

Give it a try, since "one size fits all" simply doesn't work with these aps.

Good luck.

[Mick Laver]

Thanks, Stu
I have changed the response (momentary press of -1 and +1) on the fly with some success. I haven't tweaked the others, but it might be fun to play with the gain and damp on a long transit to see what combination works best. (Providing my tweaking doesn't drive my wife crazy. Kinda like the TV remote ...)

I'd say 80% of the time the 4000+ is just fine. Is the other 20% worth the expense of retrofitting to a direct drive (and in the case of the Mk II apparently losing your aft water tank)? I think the answer is no. We'll see how the "new" settings work on the 60nm downhill run to Ensenada tomorrow.

[kwaltersmi]

I'll have to give the cocktail a try. I'm not sure what my current settings are on my 6002, but I use 2 for the response.  She's always worked well until our last two times out when it would hold course for 30 minutes or so and then wander to port and give an off course error. A quick switch to standby and then back to hold and it seemed to fix things for another 30 minutes. Anyway, maybe giving her a cocktail will jog her memory!

[Craig Illman]

This was timely. Adjusted my ST4000 today and it appears to behave a bit better. I know the fluxgate isn't in the most optimal location.

[Jim Hardesty]

Have a question about the settings.  I don't have a rudder position sensor installed.  I bought one last winter, just a lot of work to put it in my MKll.  My current rudder damp is 1.  Should I leave it as is or change it to 3?
Jim

[Stu Jackson]

Have a question about the settings.  I don't have a rudder position sensor installed.  I bought one last winter, just a lot of work to put it in my MKll.  My current rudder damp is 1.  Should I leave it as is or change it to 3?
Jim

Jim,

ITWMB, I'd simply give it a try in calm conditions and see what it does, then build up confidence in the setting differences you see depending on sea state and the direction you're heading.  We've seen, as part of this discussion that heading upwind vs. downwind can make a difference in what settings are "better" for the conditions.  Good luck, have fun trying.  I find that the more i play with the settings the more confidence I get.  Remember, I have an ST3000, but the control head algorithms are pretty much the same, and this unit doesn't have a rudder sensor, just the fluxgate right in the control head - way old technology!   

[Roland Gendreau]

I have not checked the tuning settings on my autohelm 4000 yet...but I wanted to point out that I have seen much better performance on this unit , which has a rudder position sensor, than what I experienced with the 3000 unit I had on my previous boat, a C30.  In particular, performance down wind and in following seas is much better.  It would be interesting to prove the performance improvement the sensor provides by disconnecting the sensor in some challenging conditions to see before and after performance.  It is an interesting thought, but once in challenging conditions, my interest in such an experiment might (will) wane.

Roland

[Mick Laver]

The "cocktail" worked great. We made the entire 60nm transit with following seas without having to hand steer. Admittedly the swells weren't as large as the last trip, but based on similar conditions from previous trips the new settings are definitely an improvement. Otto is my friend again. And this list is great.