Raymarine ST8002 Autopilot Won't Calibrate

Today I attempted to follow the calibration procedure for my Raymarine ST8002 autopilot. I entered the SEATRIAL CAL and turned the boat in circles slowly as instructed. I turned the boat in circles three times, but the autopilot did not complete its calibration. I tried twice more, turning three complete circles each time, but got no further response from the autopilot. I got no message saying I was turning too fast, no beep, and no indication of deviation. What do I do now?

Chances are your compass is bad. Take it out and spin a slow circle clockwise in the standby mode while watching the compass heading readout. You should see it count up 1° or 2° at a time.
I just edited my post because I thought you said you WERE getting a "too fast" message but you said you weren't. My bad.
Still it might be worth looking at the compass heading.

I didn't get a "TOO FAST" message. As I kept turning the "SWING ON" continued to display. The calibration didn't complete after three circles. The heading did increment continually. I can't say how smoothly it advanced because a slight wind made the boat not turn smoothly and drift; the boat didn't really make a circle, rather a spiral. Could the drift be the problem? It's hard for me to find a completely calm day this year!

The circles need to be relatively constant. Your boat is twin engine? Just make a smooth circle in it's own boatlength using the engines in any calm area. Your circle needs to be continually increasing with no decreases in heading while calibrating. You also need to make sure that the compass is reading all 360° with no missing quadrants if you're having issues with calibration.
I'm wondering why you're calibrating as I assume it's been done before. Is your pilot heading correct? You need to know where the pilots fluxgate compass is. You haven't stored a tool bag or anything magnetic near it, have you? Just checking.

Could your A/P compass be too close to another magnetic source? Speaker, microphone?

I'm calibrating because last season the AP reading varied from a compass reading by as much as ten degrees on some headings. When I calibrated it then, I got a deviation of greater than 15 degrees. Over the winter I realized I had put my tool box about three feet from the fluxgate compass. I moved the toolbox and was hoping that recalibrating would solve the problem.

danabbas said:

I'm calibrating because last season the AP reading varied from a compass reading by as much as ten degrees on some headings. When I calibrated it then, I got a deviation of greater than 15 degrees. Over the winter I realized I had put my tool box about three feet from the fluxgate compass. I moved the toolbox and was hoping that recalibrating would solve the problem.

Click to expand...

It sounds like you've studied your manual & have a handle on the situation but it's not uncommon to have the compass reading differ a few degrees. They're different style compasses in different locations. The pilot doesn't care what the heading says. It'll follow it and be happy all day long. The pilot heading does need to be close to your GPS COG if you want to navigate to waypoints but I digress...get the calibration issue sorted out first.