Replacing an AH800 tiller pilot?

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prv

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"George", my tillerpilot, seems to have gone senile. Nothing's mechanically wrong, the rod will still motor in and out in manual mode, and it makes normal-ish movements in auto. What it doesn't do is keep a straight course - every time we've tried to use it this year it has determinedly steered us firmly over to starboard until we have to take back control. This is new behaviour - it worked perfectly adequately last year.

First off, is there a straightforward fix?

Assuming there isn't, I'm resigned to getting a replacement. I singlehand a fair bit and rely on the tillerpilot - the boat is small enough that my weight alters the trim and hence the course so simply fixing the tiller doesn't work.

I assume my choice is between Simrad and Raymarine, and then choosing an appropriate model in the range. I have no other devices from either manufacturer. Do Simrad pilots fit onto Raymarine mounts? If not I'll go Raymarine, but if so it seems to be a free choice between them. Any reasons to prefer one over the other?

I'm well aware that manufacturer's boat size ratings can be optimistic, and will make my model choice accordingly. I'm after reaction speed in choppy water as much as raw power.

Cheers,

Pete
 
prv said:
"George", my tillerpilot, seems to have gone senile. Nothing's mechanically wrong, the rod will still motor in and out in manual mode, and it makes normal-ish movements in auto. What it doesn't do is keep a straight course - every time we've tried to use it this year it has determinedly steered us firmly over to starboard until we have to take back control. This is new behaviour - it worked perfectly adequately last year.

First off, is there a straightforward fix?
Click to expand...

Remove the large ferrous object (or magnet) which you have inadvertently placed close by. Sea Searcher magnet in the cockpit locker?
 
Ubergeekian said:
Remove the large ferrous object (or magnet) which you have inadvertently placed close by. Sea Searcher magnet in the cockpit locker?
Click to expand...

Don't have any cockpit lockers :-)

It's a good thought, and I'll have a look around. I can't think of anything though - under that seat is the quarter berth, in which the only change is a new cushion. Nothing's changed around the engine under the sole. Aft of it is the gas locker, but nothing's changed there, same two cylinders. Some minor rearrangement of the woodwork inside the cabin bulkhead, but that's several feet from the tillerpilot and not ferrous anyway. Last trip we did have a new outboard in the stern locker, but it's again several feet from the pilot and in any case we didn't yet have it when the problem started.

I have run a new power supply to the pilot as part of a general rewiring. It's an unbroken run in 2.5mm^2 cable, with a good voltage measured at the socket. It follows the same route as the original, which is nowhere near the pilot anyway. No new wires running past the pilot either. I can't see how a power supply problem would cause this effect anyway - it's not lacking power, it just deviates to starboard whether going upwind or down, or motoring.

Pete
 
prv said:
Don't have any cockpit lockers :-)

It's a good thought, and I'll have a look around. I can't think of anything though - under that seat is the quarter berth, in which the only change is a new cushion. Nothing's changed around the engine under the sole. Aft of it is the gas locker, but nothing's changed there, same two cylinders. Some minor rearrangement of the woodwork inside the cabin bulkhead, but that's several feet from the tillerpilot and not ferrous anyway. Last trip we did have a new outboard in the stern locker, but it's again several feet from the pilot and in any case we didn't yet have it when the problem started.

I have run a new power supply to the pilot as part of a general rewiring. It's an unbroken run in 2.5mm^2 cable, with a good voltage measured at the socket. It follows the same route as the original, which is nowhere near the pilot anyway. No new wires running past the pilot either. I can't see how a power supply problem would cause this effect anyway - it's not lacking power, it just deviates to starboard whether going upwind or down, or motoring.

Pete
Click to expand...

Pretty comprehensive checks - but just to make sure, why not stick a handbearing compass as near as possible to where the autopilot sensor is and check it points the right way...
 
Ubergeekian said:
why not stick a handbearing compass as near as possible to where the autopilot sensor is and check it points the right way...
Click to expand...

Good idea, I'll try to remember next time I'm out. I presume you mean to hold the compass in the spot the tillerpilot goes, without the pilot fitted. Otherwise I know exactly what the source of deviation for the hand compass will be :)

Pete
 
prv said:
First off, is there a straightforward fix?
Click to expand...

Does it rattle ? I fixed one a while back where the compass gimbal pivot had broken, so it settled in some circumstances and worked (ish) but not others. in Manual it pushed in/out fine which sounds v similar to yours. The gimbal is in the bulge at the bottom. All it took was araldite.
 
prv said:
Good idea, I'll try to remember next time I'm out. I presume you mean to hold the compass in the spot the tillerpilot goes, without the pilot fitted. Otherwise I know exactly what the source of deviation for the hand compass will be :)
Click to expand...

Tricky, because the AP supply is one possible source of problems. I suggest you try it with the AP (a) absent (b) present and (c) switched on ...
 
chewi said:
Does it rattle ? I fixed one a while back where the compass gimbal pivot had broken, so it settled in some circumstances and worked (ish) but not others. in Manual it pushed in/out fine which sounds v similar to yours.
Click to expand...

Interesting. I haven't noticed a rattle, but I haven't been listening. It didn't occur to me that there would be mechanical parts other than the drive mechanism (which is clearly fine) so I hadn't planned to open it up for a look. Perhaps I will.

Pete
 
In case I don't solve the problem, or decide to award the boat a birthday present anyway :), can anyone help with the questions about new pilots (especially Simrads fitting on Raymarine mounts).

Cheers,

Pete
 
x two

chewi said:
Does it rattle ? I fixed one a while back where the compass gimbal pivot had broken, so it settled in some circumstances and worked (ish) but not others. in Manual it pushed in/out fine which sounds v similar to yours. The gimbal is in the bulge at the bottom. All it took was araldite.
Click to expand...

My 800 rattled, on opening it, the gimballed flux gate compass was also loose, hanging by the ribbon cable. The central bolt and weight were lying in the casing.

(BTW, first time I reassembled it, I put the weight on top instead of below.... DOH!)

Nick
 
prv said:
In case I don't solve the problem, or decide to award the boat a birthday present anyway :), can anyone help with the questions about new pilots (especially Simrads fitting on Raymarine mounts).

Cheers,

Pete
Click to expand...

get a 2000+
It will fit the same as the 800, maybe even the power, and the performance is far better. than the 800 or 1000.
 
prv said:
I am certainly tempted by that plan :)
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More than tempted - I've been and gone and done it. Amazon had almost £100 off their normal price, so I took it. Feels a bit odd using "buy now with 1-click" for £400 mind :)

(They said there was one left in stock before I bought, so I don't know if the listing will still be visible now.)

I'll still try to get the old one working, as it would be nice to have a backup. I do rely on it quite heavily.

Pete
 
I had similar symptoms with an autopilot a few years ago and discovered that a broken O ring had fallen into the housing and was jamming the compass gimbals.

I would support the idea of getting a new (bigger) model and fixing the old one to keep as a spare.
 
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