Autohelm ST4000 Conversion To ST4000+ MKII

[Dave Emery]

I would like to replace my failing Autohelm ST4000 autopilot with a new Autohelm 4000+ MKII. I'm looking for input as to what will need to be modified to use the new unit. Will the existing pedestal bracket work with the new Wheel Drive Unit? Does the control unit use the same size hold for mounting as the old unit? Are the cables the same length?. If you have any expierence with replacing a ST4000 with the new ST4000+ MKII unit I would appreciate any information you can share.Thanks, Dave

 

[Peter Brennan]

Yes and no

The new control head on the ST4000+ requires a bigger hole and different placement of the securing nuts. I just opned up the old hole to fit. As for the cabling, I just disconnected them from the old one (which I sold on EBay, by the way) and connected them to the new one. The cable on the new flux gate compass was plenty long enough. Indeed, I relocated it to a new and better position much further away from the control head than the old one had been. Not sure about the wheel drive, which I intend to replace, but it looks to me like a drop-in replacement.

 

[RG Miller]

just replaced mine

The new one doesn't fit the old holes (of course) but after making it fit, the rest just plugged in....Now the bad news...it's not working right...It won't hold the course...keeps over correcting. The autohelm people have told me to change one of the settings from what the book says, but I haven't had time yet. I sure hope it works.Don't mean to scare you but I'm a bit pissed off about it.

 

[Brent]

Auto-Helm Oversteer

I have a 1990 Hunter 335 with Autohelm ST4000+. I just recently bought this boat and was having the same problems with oversteer. I finally got out the manual and followed the procedures for initial sea trials and now it works fantastic. The key to proper operation is the rudder gain and response settings. You will have to adjust them to your particular boat and it's handling characteristics, but I have found that the Response Setting of 2 works much better than 1.Good Luck,Cap'n BrentS/V Elena Lua

 

[Peter Brennan]

Flux gate location

Heed the instructions on location of the flux gate compass. You want it in the middle of the boat as far from big chunks of iron as feasible. Initial position of ours as it came with the boat was under the galley sink. When any one tossed a knife or fyring pan into the sink the Autohelm went nuts. Even so, the setting for deviation (I think) is supposed to be less than 22 degrees. The original location barely made it. The new location far from the sink and engine comes in at less than 5 degrees.