Re: [Amel Yacht Owners] Autopilot failures and spares

Bill & Judy Rouse <yahoogroups@...>


I am sure that Bill Kinney will give you all of the details, but when doing your project, remember that Raymarine drives, and others, switch from one direction to the other by reversing polarity on the DC voltage drive units, linear and rotary.

The reason that I point this out to you is that the drive units need to be in sync regarding causing the boat to turn to port and/or starboard. The drive units on BeBe #387 are wired to the A/B switch with the linear the opposite polarity of the rotary because of the geometry of mounting the linear. 

Also, remember that a 24VDC Raymarine Rotary or Linear drive will have a 12VDC clutch. This means that there are four wires going to the drive units:
  1. 12VDC positive to Clutch
  2. 12VDC negative to Clutch
  3. 24VDC positive in one direction, negative in the other going to the drive motor
  4. 24VDC negative in one direction, positive in the other going to the drive motor
If you can get your head around these points, the actual installation should be easy.



On Wed, Feb 15, 2017 at 2:26 PM, Stephen Davis flyboyscd@... [amelyachtowners] <amelyachtowners@...> wrote:

Hi Bill,

We own hull #72, and the boat originally came with only the rotary drive above the galley, and one autopilot. I have since installed a complete 2nd autopilot, and have made an adaptor plate for the quadrant which will allow me to install a linear drive on the quadrant. As it is now, I have to do some minor re-wiring to switch from autopilot A to B. I really don't have a clue how to wire the autopilots or 2 drive units to switch back and forth easily. 

When you have the time would you mind providing me some more details of how you wired Harmonie to easily switch between drive units and autopilots? Any help you can provide is greatly appreciated. I plan on starting the installation of the linear drive while in St Martin in March, and will try out the system as we work our way to Panama for our canal transit in 2018. My personal email is flyboyscd at Gmail dot com. 

Reg ards,

Steve Davis
Aloha SM72

On Feb 14, 2017, at 21:18, greatketch@... [amelyachtowners] <> wrote:


I don't doubt that 10% number for a minute!  It certainly squares with what I have seen.  Looking at the archived survey data from the Pacific Puddle Jump would gives a number at least that high and likely higher.

When we bought Harmonie she had two autopilots and two drives installed in the usual Amel configuration of a linear drive at the quadrant and a chain drive at the wheel. They were, however, not switchable. One drive was wired to one computer.  If there was a failure, you would have to do some rewiring to swap drives from one pilot to the other. It was also possible to inadvertently turn both on, which would lead to same serious problems with the steering gear as the two drives fought each other.

I installed a pair of 4-pole, double throw, Form C, switches. Now with two toggles over the sink I can hot swap either computer to be the active one, and use either drive, with no risk that both can be turned on at the same time. I very much like this arrangement, because the two computers have different strengths, as do the two drives.  Being completely separate, systems all parts are duplicated.

It is really helpful to my piece of mind that the entire "spare" autopilot system is installed and exercised on a regular basis. I know it will work when it stops being the "spare" and starts being the only one!
Bill Kinney
SM #160 Harmonie
Providenciales, Turks and Caicos Islands.

---In, wrote :

Bill Kinney referred to my mention of "10% of autopilots fail on ocean crossings." Maybe there is some doubt that this number is accurate.

I should have given everyone more inform ation about where this 10% number comes from. The 10% agrees with my experience with other 
boats crossing at the same time as we did. Many times while you are circumnavigating, you will cross in the loose company of 
others...seasons cause the migration at certain times.

I also asked the founder of the ARC and the ODYSSEY, Jimmy Cornell. In his vast experience, 10% of the boats crossing will have an autopilot failure. 

I strongly recommend having a backup for each component of your autopilot system during ocean crossings. Normally this includes:
  • Course Computer
  • Control head
  • Electronic compass
  • Rudder reference
  • Drive unit
I also recommend a backup GPS and any component such as an antenna.

There is a way to "rent" these backups for very little money. Buy them and sell them after your crossings a re complete. I bought ours from Dan Gerhardt>. Dan sells new old stock and refurbished Raymarine components...and will repair anything Raymarine. I believe that a number of Amel owners have used Dan with complete satisfaction. 


Currently Galveston

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