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Autopilot Drive Mount

John MacDougall, Annie Laurie, #26

This is an important piece of info for ALL 470 owners and I hope someone will put this note into the Mainsheet as well, for the benefit of all Catalina owners.

As many of you know, this past summer during my eastbound Transatlantic crossing, I experienced some autopilot troubles, and ended up doing a LOT of hand steering, including the last few hundred miles of my crossing.

These autopilot troubles were NOT Raymarine problems (I upgraded to ALL new Raymarine electronics 14 months ago), but were Catalina / Catalina Dealer caused problems, with the autopilot drive mounting.. I recently confirmed, with Gerry Douglas, that some 470 autopilot drives are/were factory installed and some are/were dealer installed. He had no info whether mine was done at the factory, or dealer.

In any case that point is moot since others may have this potential problem lurking in their lazarettes, and not even know it.

Please understand, this is NOT a knock on Catalina, but rather a heads-up to all 470 owners and some info on what I did to eliminate the problem (and NEVER have to worry about it again).

The way my Raymarine drive was mounted, (either at the Catalina factory in St. Pete OR the original dealer in CT) was with 4 - 3/8" stainless Carriage Bolts, thru-bolted to the bottom transom step / swim platform. These Carriage Bolts have a small square head on the bottom side of their smooth top, which was supposedly going to hold into the glass of the transom/swim platform, and allow for the bolts to be tightened from below. While this did work when installed, after years of use they'd worked their way loose enough to "round-out" the glass and in essence, become difficult (if not impossible) to tighten sufficiently.

When installing the new autopilot drive last fall, my brother tightened the lock nuts on the inside of the lazarette (holding the autopilot drive bracket), while I was pushing down hard on the top of each bolt, allowing them to be tightened as best as possible. My brother is a ASE Master Mechanic and has owned his own auto repair business for more than 30 years, so when he said that's as good as we're going to get, I took him at his words.

BUT, I should NOT have done so. What I should've done is stop right there and redesign the mounting design. But, I made a bad assumption. I assumed since it had worked fine for the past 6 and 1/2 years, it would be fine. (Mistake #1) {at that time, I had NOT finalized my decision to sail across the Atlantic the following summer.} Ah, but alas, that was not to be.

Sailing across the ocean puts a LOT of stress on things, since it is constant 24 hours a day, 7 days a week, for weeks on end. Things that would normally last years, may break in weeks. And that's what happened. During a gale, North of Bermuda, we lost autopilot operation. It was at night (naturally!), and when things calmed a bit (wind down to 25 kts and seas down to 12') the next afternoon, we found the problem.

All 4 nuts were gone (in the bottom of the lazarette) and the autopilot bracket was securely attached to the drive unit, and both were sitting nicely in the bottom of the lazarette, and still attached to the rudder/tiller arm.

Well I didn't have long enough 3/8" bolts on board to simply replace the carriage bolts, but I did have long enough 5/16" bolts on board. And in the middle of the Atlantic Ocean, in 10' - 12' seas and 25 kts of wind, we affixed the bracket back in place with the 5/16" bolts and lock nuts. This worked fine and got us the remaining 2000 miles to the Azores.

While in Horta, Azores, we inspected our repair and found it all tight and secure. So, I made the decision to go on without any further repair (Mistake #2) On our way to Gibraltar, we had a failure of the autopilot clutch wire, and made repairs in a couple of hours, by replacing the autopilot clutch wire entirely.

A few days later (about 300 miles from Gibraltar), we had another autopilot failure. The 5/16" bolts had loosened and the lock nuts fell off. So we again had no autopilot, and were hand steering.

I made the decision, since we were approaching the crowded shipping lanes near the tip of Portugal and then we'd be in a lot of traffic heading to/from Gibraltar (as well as North/South traffic), that we would simply hand steer the rest of the way.

It was tiring for us, since my crew was just myself, my sister and a friend of ours (3 people total on board) but we made it just fine.

In Gibraltar, I hired Sheppard's Boatyard / Workshop to redesign the autopilot mounting.

I now have an almost indestructible autopilot drive mount!!!! I have a thick 316 stainless plate (approx. 6" square) with 4 - 10mm 316 stainless bolts/studs welded to it, mounted on top of the bottom transom step/swim platform, and another 316 stainless backing plate epoxied/glassed into the underside of the bottom transom step/swim platform (inside the lazarette), and the Raymarine Drive bracket secured to the studs with 316 stainless flat washers and lock nuts.

The 10mm size was necessary due to the sight enlargement of the original holes. The nuts can be tightened down VERY tight and NOTHING moves and it just will not come loose very easily.

This new design was tested during my return passage, Westbound crossing the Atlantic this fall. 3,700 miles + Autopilot ON the entire crossing and NO troubles at all!!!!

Mostly all with heavy following seas,
more than 2 weeks of 10' - 12' seas and 20 kts + winds
AND 3 days of Tropical Storm Olga winds of 30 - 35 kts. and seas of 15' - 16'+
And, after arriving in St. Thomas, when we inspected the new mounting design and tested the studs/nuts, they were all still completely tight and secure.

So, I now have no worries about my autopilot. But, I do have concerns about how Catalina and/or Catalina dealers mount/install the autopilot drives, on other 470's.

(Click on picture for full size)

Autopilot Drive Mount


Autopilot Drive Mount


Autopilot Drive Mount


Autopilot Drive Mount