Simrad Auto Pilot Issue

[RyanB]

I have a Simrad A22 Auto Pilot, that works really well until I try to troll on port engine.

When salmon fishing we need to go slow, ~2.5mph, so its standard cut an engine and troll off one for X amount of time, and then start the opposite side and do the same thing. It slows the boat down and saves on fuel too.

The problem is, the AP only wants to keep its heading when running off the Stbd engine. I can troll for hours using the stbd engine. The moment we switch to the port, the AP loses its heading, typically turns hard to stbd, and we're forced to manual steer. Which is a bigger deal that it sounds at times, and requires someone at the helm all the time.

Any ideas what could cause this? The unit stays powered up on port engine, I've even left the stbd ignition on to see if that would help but it doesn't. If I start the stbd engine and let it idle, everything works fine, shut stbd down, and she loses heading. Weird.

I feel like I'm missing something stupid here, but can't figure it out. Shouldn't the AP work as long as the AP is powered up??

 

[Captain Ralph]

Easy thoughts first, what engine has power steering (if any)?
Is the pump motor still powered on, not just the head?

Next, hard to explain but simple to fix, Re-calibrate your rate compass.
This is when you turn the boat slowly in a circle.

Fields of flux around the earth make a magnetic north, Fields of flux are around your boat, engines, bilge pumps, batteries and wire harness make their own mini flux lines.
Then the rotation of the earth and the way you hold your jaw combine up to affect your rate compass.

I do it in both directions when commissioning a set up.
Interesting sometimes I get an error spinning one way and no error the other. Usually have to relocate the rate compass when this happens.

Go to your AP setup and calibrate your compass in a long slow circle. The AP display will guide you to fast or to slow.
Repeat it again in the other direction. If no errors, you should be good to go.

This may be the first thing Navico/Simrad will ask when you call them.

 

[Captain Ralph]

Which is a bigger deal that it sounds at times, and requires someone at the helm all the time.

Thought I read this but was not sure, Was just trying to be helpful earlier.
Back now and found it as I was scared I would.

Somebody had already been at the helm all the time..

 

[RyanB]

Easy thoughts first, what engine has power steering (if any)?
Is the pump motor still powered on, not just the head?

Next, hard to explain but simple to fix, Re-calibrate your rate compass.
This is when you turn the boat slowly in a circle.

No Power steering, just Hynautic system.

I'm 99.9999% the pump is powered on, as I could swear I've heard it while running on the port engine. But, now you've got me wondering, so will check that this weekend to make sure.

Thanks for the reply, will try to recalibrate this weekend as well. I would have thought is its calibrated enough to run fine of stbd it wouldn't matter but cant hurt to give it a try.

 

[RyanB]

Thought I read this but was not sure, Was just trying to be helpful earlier.
Back now and found it as I was scared I would.

Somebody had already been at the helm all the time..

Not sure what you mean, but assume you're referring to someone not being at the helm if AP is on....

We're 4-6 miles of the shore, in 500' of water, without another boat insight 95% of the time. So, if someone runs down, quick, to help net a fish or untangle something, we're still being safe. Most of the time we never even see another boat, until we're back at the marina. We're always as safe as we can be.

The reason I said that, is in the case where someone has to run down to help with something, the boat can get of course, typically via a sharp turn, and we tangle everything to hell as lines speed up or slow down. 9 lines in one big rats nest really sucks