Repair or Replace Autohelm ST7000?

[Whitebread117]

42' monohull, 28k lb displacement, cutaway forefoot shoal full keel, skeg rudder, center cockpit.

I bought the boat with a nonfunctional ST7000 quadrant mounted AP and a S4000 wheel mount unit. The 4000 is fine for motoring in calm water- it's useless in any kind of swell or under sail (heavy boat, likes 15kts + sailing).

The ST7000 head unit doesn't power up when power is applied. Before I spend too much time on it, is this unit new enough to be worth repair? I'm not in front of it now, just budgeting boat projects for the next couple months.

All I'm after is an AP that will hold a rock solid compass course in any reasonable sea state. We navigate with navionics and a couple tablets- I'm not looking for any AP interfacing. We're a power hungry boat with multiple charging means, so efficiency isn't highest priority.

So is a ST7000 worth repairing for an overweight 42' cruising monohull, or is there a better option for a simple robust AP?

(Wind vanes are out, no room to mount and no passages longer than 48 hours for now)

I like saving money, but I'm willing and able to pay for a better product if one is available.

Thanks!

[GordMay]

FWIW:
Here’s the Service Manual (/w Schematics & etc)➥ http://www.olajedatos.com/documentos...ice_manual.pdf

[Frankly]

I would first check out the 7000 actuator. Basically it is a DC motor connected through an electric clutch and gear box to the rudder drive.

Disconnect the drive connector/ cable and apply 12 Volts to the two motor leads. If you hear it turning then reverse the polarity and see if it runs in the opposite direction. Next apply 12 V to the clutch and see if it engages. If this passes try engaging clutch and applying power to the motor. The rudder should rotate but be careful about not driving the system into any mechanical stops. Your source of 12 Volt power should be via a 20 Amp fused/ breaker circuit.

If the actuator is working properly then might want to replace the front end with something newer. Don't think you are going to get Raymarine to help on repairing the old 7000 system.

This is all assuming that you have at least checked that the 7000 is getting 12 V power.

[ka4wja]

Whitebread,
1) First off, we don't know what boat you have, nor what year, nor where you are at, nor where the boat is at, nor where it was commissioned, nor what year the electronics were installed/commissioned, nor where they were done...
Nor, do we know if you've even got 12vdc powered to the autopilot??
And, while knowing that you won't have any passages more than 48hrs long, that can be vastly different heading along a benign coast, versus punching through some steep seas...
So...

So, all I can do is provide you with some generic advice / input...

So, here it is...
--- Repair your existing autopilot...



2) As for some details....
You need to find your autopilot....I assume it's an S3 (or S3G), or Type 400 (or 400G)???
The ST-7000 is the control head only, and the linear drive (Type 2 ???) is the part attached to your quadrant...
And, you need to see if it has 12vdc power???
And, whether the ST-7000 control head is wired to it correctly, and check for corroded / loose wiring of all the autopilot connections (or which there are many)...

The actual autopilot is called the "corepak" (sometimes called the "course computer"), and is the box that does all the work....it takes in your vessel's heading (from its external heading sensor), and your rudder's position (form your external rudder position sensor), and adjustments to your course, etc. (from your ST-7000 control head).....and calculates/adjusts your course accordingly, sending power to your linear drive attached to the quadrant....

Depending on the age of your Raymarine equipment, this could be an S3 (or S3G), or the smaller S2 (or S2G)....or even an older Model 400 (or 400G), or the smaller 100/150 ???

This is your autopilot....It's a black or gray box, about 8" - 10" long, 3" - 4" wide, and 1.5" thick....
It will have a heading sensor wired to it...and a rudder position sensor wired to it...
As well as the ST-7000 control head wired to it, and the linear drive wired to it...
(it may also have another "Sea Talk" data cable, and/or a NMEA data cable, for other instrument data and/or GPS position data...but, not necessarily...)



3) Once you find your autopilot and examine the wiring, confirm its powered properly, etc....then you can test/evaluate it, and pass on that info here to all of us (along with the details referred to above, in #1)...
And, then we can be of more help....



4) Back to your original question....

Originally Posted by Whitebread117

All I'm after is an AP that will hold a rock solid compass course in any reasonable sea state. We navigate with navionics and a couple tablets- I'm not looking for any AP interfacing. We're a power hungry boat with multiple charging means, so efficiency isn't highest priority.

So is a ST7000 worth repairing for an overweight 42' cruising monohull, or is there a better option for a simple robust AP?

(Wind vanes are out, no room to mount and no passages longer than 48 hours for now)

I like saving money, but I'm willing and able to pay for a better product if one is available.

Yes, the autopilot you have (assuming we get it working) is a good unit, and it will certainly be able to hold you on-course in many sea states and even in heavy weather....
Nothing wrong with it at all!!

But, we don't know if it even has 12vdc to it yet...so what it will take to get it working??? Could be just replacing a fuse inside it??? or could be it's toast....
We just don't know yet....

{FYI, worst case, figure on $2000 to $2500 for new (or replacement) corepak.....best case, a dollar or two for a couple new fuses and/or wire terminals...}


Hope this helped??

Fair winds...

John