"Crazy Ivan" the Autopilot

[Stu Jackson]

...And I believe cross track error is also the difference in your compas heading and the course the boat is actually moving.

Mike,

Sorry, nope, not true.  

Cross track error is the distance . LEFT OR RIGHT, that you are off course from the line between where you originally entered the GO TO (your "start" point for lack of a better phrase) and the waypoint you are going towards.  That original line.  Period.  Nothing more, nothing less.

Reason I know this is that we started with a Loran and moved to a digital-only Magellan GPS way before charting GPS became available.

Kinda a separate issue, but as far as your "quote," Mike, think of this situation:  

You're heading up a river and get caught in a whirlpool.  The river runs due north-south and you're heading north.  Your boat gets caught by the whirlpool and now the bow is pointing due east.  But the boat is still moving due north through the water.  Your heading is still 0 degrees (north) 'cuz this is the direction the boat is moving) but your compass reads 90 degrees (due east).  Your cross track error is zero, so your example has nothing to do with cross track error.

[Mike and Joanne Stimmler]

Stu,
Thanks for setting me streight. You have such a good way of splainin things.

Mike

[Stu Jackson]

A link to here has been added to "Wacky Autohelms" in the wiki (electronics)

[SD Diver]

The only time I engage the auto pilot is to lock the wheel while I adjust sails, we call it "Iron Mike"

Ralph

[Indian Falls]

Here's one no one has mentioned:

Mine was was all over the place, it would work ok then take a turn in either direction or it would jitter back and forth then settle down a bit.  I never let it go long enough to see it it would come back.

I finally took my 4000 home and opened it up.  It was wet inside with about 2 tablespoons of water sloshing around inside.  I dried it out cleaned off the corrosion, cleaned any removable connections and it now works perfectly.  I use it all the time when single handing and I never keep out in the wet weather.  Mine is mounted below the port side engine control panel.  (use just a little anti-static precaution and you'll be fine, just don't rub your feet on the carpet and then touch the board)

[Michael]

Brian - and anyone who has got this far because you have problems with the Autohelm Raytheon ST4000 Autohelm Wheel Pilot:

When mine - also on a 1997 MkII - went intermittently awol a couple of years ago, after considering the electrical possibilities, I took the drive unit apart and found the belt worn out.  Replacement belts are available from 1-800-859-7659, www.polybelt.com, 26 West First Street
Clifton, New Jersey, 07011. Item number BAT5-750AUTOST4000.  Price (then) $19.95. The belt I had met these criteria:

belt measures 750 mm in length; tooth groove is 1.16 mm in width; distance between tooth grooves is 3.22 mm. Groove is a U with a V at the bottom of it.  Belt is 2.93mm thick and 9.33 mm wide.  There are 150 sections between grooves in the full length of this belt.  The thickness of the belt from the back to the bottom on the V is 1.67mm.

Brian, it may well be that your problem is not so simply remedied - and perhaps if I read your postings more carefully I would know that - but someone else might find themselves reading through your interesting postings and have a belt problem, so for what its worth.