Electric or Hydraulic for Backup autopilot?

[SailingHarmonie]

Originally Posted by Muaddib1116

Thanks! That's really close to what I have in mind. How do you manage to have both drive units attached to both ACU's and then have only one drive be able to be activated at a time? Is there some sort of 3rd party switching system?

Is your linear drive electric or hydraulic? Why did you choose that type? What type of boat do you have? Size, displacement?

Why do you use the linear drive as primary over the rotary chain drive? Have you noticed any issues with leaving one of them inactive for extended periods? for instance the spare linear drive you keep? or do you periodically switch to the other unit to exercise it?

The linear drive is electric. The Raymarine is a very nice piece of kit. Very quiet and smooth.

Details about switching system here: https://fetchinketch.net/boat-projec...ded-autopilot/

The reason we use the linear drive as the primary is that it runs directly off the rudder post, the chain drive runs the rudder through the cables.

The boat is 53 feet, 38,000 lbs. We switch over to the alternate computer and drive every few days to exercise and test them. The linear drive that is a backup, just sits and waits. It is kept dry, it works when we need it.

[Muaddib1116]

Thanks, that diagram is really helpful! I'll definitely think hard about how I want to switch between units.

A question that just occurred to me is how are the fluxgate compasses mounted? I assume that your system has two separate compasses, one attached to each computer? From what I've read, it seems like they need to be placed in pretty specific locations, but can you mount two fluxgate compasses next to eachother?

Thanks! this is really helpful stuff!

[SailFastTri]

Originally Posted by Muaddib1116

Thanks, that diagram is really helpful! I'll definitely think hard about how I want to switch between units.

A question that just occurred to me is how are the fluxgate compasses mounted? I assume that your system has two separate compasses, one attached to each computer? From what I've read, it seems like they need to be placed in pretty specific locations, but can you mount two fluxgate compasses next to eachother?

Thanks! this is really helpful stuff!

Not just fluxgate compasses, but full redundancy also means redundant rudder position sensors.

[Muaddib1116]

Originally Posted by SailFastTri

Not just fluxgate compasses, but full redundancy also means redundant rudder position sensors.

Yeah, I was wondering if you could T off the position sensor wires to a second computer, but if I can fit a second drive unit, I feel like a second position sensor should be no problem. I'm just wondering if I can mount the second fluxgate compass right next to the existing one. Since only one should be on at any given time, will the inactive compass interfere with the active one?