Logo
FULL SITE MENU

Autohelm

B

Bruce53

Member
I have an ST4000 Raymarine autohelm. The slack in my helm drive requires a rudder reference transducer which costs around $200. I am a poor/good (meaning not wealthy but crafty with electronics) electrical engineer. Seems the rudder reference is probably dual-pots or a center-tapped pot that should not be too difficult to construct if I could find out what the values are. Raymarine (Raytheon) will not disclose the design, of course. Anyone have any suggestions as to how I could dig up a schematic or design data on the thing.
Many thanks for any help on this one...
Cheers
 
It is a sealed pot...has a 5.0 VDC reference and the output (rudder) angle is represented by the output voltage (using the pot as a voltage divider). Use the calibrate function to see what the volts/deg transfer function is...the phase is reversed by switching polarity of the reference. The hard part will be the mechanical linkage/mounting...These transducers are usually only required for hydraulic helms...
 
Thanks Makomark.... Yes, the manual says it is needed in the hydraulic helms but it adds that it is an aid to stability if there is undue slack in the helm/rudder linkage, which is my case: tends to wander a lot. From your answer here, I think I could build one. Just did not want to damage the controls with higher than expected voltages.
Sure do appreciate your help here....
Skol to the Northland, Skol
 
Bruce53 said:
I have an ST4000 Raymarine autohelm. The slack in my helm drive requires a rudder reference transducer which costs around $200. I am a poor/good (meaning not wealthy but crafty with electronics) electrical engineer. Seems the rudder reference is probably dual-pots or a center-tapped pot that should not be too difficult to construct if I could find out what the values are. Raymarine (Raytheon) will not disclose the design, of course. Anyone have any suggestions as to how I could dig up a schematic or design data on the thing.
Many thanks for any help on this one...
Cheers
Click to expand...

Ayuh,.... I've got 1 of their Sport Pilot+ units on my tinbarge,...
It works just fine at speeds above 5 mph,...
Below that, it gets wind-blown, 'n lost in a hurry...

I bought the rudder transducer, 'n Ayuh, yer Right,... It's just a pot...
Shortly after mountin' it, 'n tryin' it, it fell apart,...
The shaft slid right out of it, as it's only retained by an o-ring....
I call tech support, 'n explained my problem, in that I needed a meter value, to push the shaft back in at Zero...
Unfortunately, that was Years ago, 'n I don't know where that note is now-a-days...

I redesigned the mount, 'n it's still there doin' it's job,...
'n it's the same auto-pilot as it was,...
Over 5 mph, 'n it'll track a course, or gps track like a bloodhound...
Under 5 mph, unless yer headed down-wind, you'll be goin' elsewhere 'bout as soon as ya let go the wheel...

I've been hoein' out my cave, here in the dead of winter,...
If I run across that paperwork, I'll be sure to come back to this thread, 'n post the values for ya,... ;)
 
Thanks Bondo...
Sounds bad. You say it works ok when you are doing over five knots; I need three knots for trolling. I haven't had it back in the bay yet but I am hoping that the thing will keep bumping the rudder (outdrive) over enough to get back to the heading I want and then the feedback will keep it close enough that I won't run into anyone...
Cheers
 
Back
Top