Dodgy Autopilot Question

[stevensuf]

ok got a new boat the autopilot does all its supposed to do in the marina , but as soon as at sea it quits after a few turns, im guessing the motor is weak checked all terminals , power fine no corrosion, now in the marina if i set a course on the autopilot i can manually force the wheel off the course, should i be able to over ride the autopilot with brute force? or is this a sign that the motor or clutch is week?

sorry to ask never had an autopilot before so not sure about how hard they control the wheel!

[Chief Engineer]

If you have a wheelpilot...don't force the whhel.

What do you mean "it does what it is supposed to do in the marina.

DQ....Have you a Manual?

[donradcliffe]

You should not try to force the wheel when the autopilot is on, but if you can turn it fairly easily, there is something wrong with the drive. We need to know a bit more about the autopilot--what brand, what kind of drive, etc. If a ram drives the quadrant, it is either mechanical with a solenoid clutch or other means to disconnect it, or it is hydraulic, with a solenoid bypass valve. If its belt driven, the belt can slip.

[stevensuf]

ok when im in the marina if i click the st600 to auto and press say +10 degrees the wheel moves ,say i click - 10 degrees the wheel moves again, when under way if i set it to auto then click -10 degrees ,nothing much happens ,then about 10-20 seconds later i get a drive stopped error message from the display and the autopilot cops out.

the clutch appears to be engaging and the motor turning, all ok when not under way, but under way it appears not to do much then quit on me, what im wondering is if the drive is weak an unable to steer when underway when there is a greater rudder force required.

My main question is whether i should be able to manually force the wheel when the pilot is engaged? should i be strong enough to do this? or is the pilot motor weak or the clutch slipping, if it is possible to force the wheel by muscle against pilot under normal operation then i know the fault lies else where.

[Bash]

I don't mean to frustrate you here, stevensuf, but we're still going to need a bit more info than that it's an ST600. (By which, I think you mean to say ST 6000, yes?) The ST 6000 comes with three different types of drive units.

It's possible that your drive unit is faulty. However, the situation you describe could also be a problem with the quadrant, et cetera. If the quadrant is loose, the drive may have enough power to move the rudder in the slip, but not enough to turn the boat when the rudder is working against weather helm.

The simple answer here is that if you have an ST 6000, you should not be easily able to overpower the drive unit regardless of which type of unit you have. This, of course, applies unless you've set the unit to subject itself to manual override, which is an option on the ST 6000, one used more by powerboats than sailboats for obvious reasons.

[sabray]

Check the connections On the computer weak connection to drive or clutch will do this. Get the manual and walk through all the settings.. Call ray marine leave a message and you will get better tech help then waiting for the first guy to answer. Mine did this it would work and then minutes after being engaged it would give the drive error. Still have not found the solution. Thought it was bad diode. Soldered new diode in. No joy. Definitely had a bad connection on the drive output. Ray thinks the computer is shot I had a spare drive motor so tried that too. Still no joy. I cannot push against my pilot must disengage to move wheel

[donradcliffe]

Depends on your steering system, but for example, I have a 5 ft wheel, 3 turns lock to lock, and 40 degrees max rudder angle, with the drive mounted 12 inches out on the quadrant. That gives me 5/2*3*360/80= 10:1 mechanical advantage.

If I pull on the wheel with 150 pounds of force, that will put 1500 pounds of load on my ram, which will likely break the wee plastic gears in a Raymarine linear drive (which is why I don't have one).

So the simple answer is yes, you can force the wheel to turn when the drive is engaged, but no, you don't want to.

[stevensuf]

ok the controller is the st6000, the brain unit is a type 300, the drive is a whit lock, it has twin wheel stearing with chains that go to a gearbox type structure, this in turn has the motor attached, the other side of the gearbox has what looks like a con rod attached to the rudder stock, which on the side is the rudder position sensor.

[stevensuf]

well i looked up the drive unit and it has an 1800 lb rating, i have twin wheels only about 3 foot with 3 turns to lock, i doubt i have a 10:1 ratio, though it is geared below decks.

On the delivery of the boat we went through f7/8 and it took pretty much all my might to keep control and id say that was more effort than took to over power the autopilot.

Though after some thought im beginning to think its a brain box prob

[Chief Engineer]

You may have to read the manual and setup the unit. If the Autopilot has been off the boat....or the boat has been moved to a new location....you will have to follow the setup instructions.

You NEVER FORCE THE WHEEL. You will break something.