[CA] [CA11] Autopilot upgrade

[rfadler]

Hi,

I have a 2005 model year 43' sailing catamaran that originally came with all Raymarine equipment. Last year I replaced the chart plotter and wind instruments with an Axiom Pro 12 and and i70s but didn't replace the autopilot as it was working fine.

Now the autopilot is no longer working fine, it switches from auto to standby with no warning. I think it's time to replace it. It's a ST7000 control unit with a Type 100/300 course computer and a Type 2 rotary drive.

I'd like to keep the Type 2 rotary drive as it's the most difficult component to replace and seems to be working fine.

What do I need to buy? I'm guessing an ACU-400 autopilot, EV-1 sensor, and a p70s control.

Is this correct? Will the new unit use the old fluxgate compass (I'm guessing not)?

Thank you!

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum rfadler,

Should the vessel's batteries be fully charged and the vessel be operation under power and the autopilot drops into standby when operating in Auto (not Track) mode, then the reported issue may be indicative of insufficient power to the autopilot course computer. Insufficient power may result from any of the following:
- depleted batteries - fully charge vessel's batteries and then test the system while under power with the engine(s) charging the electronics batteries
- deteriorated batteries - it has has been noted that the batteries have been load tested
- poor electrical path to autopilot course computer - the power and ground paths should be inspected from the autopilot course computer through any breaker/fuse panels to the batteries and grounding point to ensure that the conductors are in good shape, are free of corrosion, and are tight.
- a failing drive unit - a drive unit which is failing or in need of service may draw excessively high current, causing the reported symptom. Should the first three items listed above have been verified, then it would be recommended that the drive unit be replaced or sent to Raymarine’s Product Repair Center to be bench checked / serviced.

Should no fault be found with the drive unit, then would would indeed be correct that an ACU-400 would be required if replacing the current autopilot with an Evolution autopilot. Raymarine offers the T70161 EV-400 Sail which includes all of the Evolution autopilot component listed on the T70161 EV-400 Sail web page. The EV-1 CCU (supplied with the T70161 EV-400 Sail will be installed in place of the currently installed fluxgate compass.

[rfadler]

Thanks for the insight. I had no idea the drive unit could be the cause. We did verify the power source and ground connections were good. As this is a sail boat it's preferred to be operated under sail without the engines charging the batteries. The house bank provides the power for the autopilot and while it's a new bank with substantial reserve it is very possible that other electronics could be pulling momentarily pulling the voltage down too low. What is the low voltage limit of the course computer? Does the ACU-400 have a similar low voltage limit?

Thanks again

[Chuck - Raymarine - Moderator]

rfadler,

Q1. As this is a sail boat it's preferred to be operated under sail without the engines charging the batteries.
A1. This action was directed for troubleshooting purposes alone. As suggested, should the problem not manifest itself when operating under power, with the engine charging the electronics bank, then the fault would be determined to be insufficient power to the autopilot.

Q2. The house bank provides the power for the autopilot and while it's a new bank with substantial reserve it is very possible that other electronics could be pulling momentarily pulling the voltage down too low. What is the low voltage limit of the course computer?
A2. 10.8V. The drop need only be temporary (ex. surge demand) for the limit encountered.

Q3. Does the ACU-400 have a similar low voltage limit?
A3. Yes.