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Autopilot failure shearing bolts

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Ian2019 View Drop Down
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Joined: 04 November 2019
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    Posted: 29 October 2020 at 19:48

Brake hub and Autopilot failure shearing bolts

A few months ago I picked up my new (to me) H385, she is a 2014 build.

Of cause before purchase we had a buyers survey which highlighted a few minor items which the owner and I agreed had to be sorted before the final purchase. However then came along the coronavirus which made the purchase a challenge as the yacht was in Spain and travelling was difficult. But in the end I took over my eagerly awaited prise.

However on the first night of our maiden voyage from Spain to the Adriatic an error came up on the chart plotter display saying “lost chart information”, so no big deal, just restart. Being single handed before restarting the system from the main control panel in the cabin I locked the starboard helm on the brake hub. After a few minutes the chart plotter was up and running with no problems.

On loosening the brake hub there was a squeaking noise (really annoying) from the upper part of the stbd steering column on every movement of the autopilot.

On arrival to the next port I had some one look at the steering column for me, although he admitted he was not really familiar with the system and his investigation was not in any way in-depth.

I will note here that the steering compartment top was not screwed down.

On leaving the port the squeaking noise was still annoying, however, after a several hours it lessened to an acceptable level and then progressively got less and less until it stopped.

After several hours and in an increasing sea and wind an autopilot alarm came up on the chart plotter, looking down at the steering compartment the top was now raising and falling 4-5cm and moving around, imaging the film alien. On lifting the steering compartment top as much as we could it was apparent that the auto pilot had become loose. Of cause you need the swim platform down to get the compartment top off and do a proper inspection. So we decided to go back from where we came as it was shorter than to where we were going, and I knew a safe and good anchorage.

On arriving at the anchorage we took the top off the steering compartment off and was shocked at what we found.

The autopilot had sheared two of the four x 8mm holding down bolts and ripped the third out of its thread, further bending the link rod between the autopilot and the steering quadrant.

On further investigation it seems as the brake pin had never been secured to the hub on the stbd steering column, as it had been on the port steering hub. Therefore, every time the stbd brake had been applied it had never been releasing, and ever time it had been applied it had been locking tighter and tighter. The autopilot was sent off to Jefa for repair and service.

After full repair and service the autopilot was secured slightly further astern in new threaded blot holes

The system was tested several times and all worked fine. However after 290nm the chart plotter reported no ruder response. Upon arrival at our next port a B&G engineer came and checked all the wiring loom etc which he reported to be fine, but he did find the 10amp fuse in the steering compartment to be blown. After replacing the fuse and completing several tests successfully all seemed fine.

Off we set sail only for the same 10 amp fuse to blow after only two hours, changed the fuse which instantly blow. So back to where we came from. B&G checked out the wiring loom and changed all the connections. Replaced the blown fuse with a 15 amp tested all successful then replaced the 15 amp with a 10amp. Ran the system on “Hold heading” for more than 12 hrs with no problems.

However, the autopilot blew 6 x 10 amp fuse on the way to the Adriatic.

Jefa agreed to supply a new auotpilot (at discount price) after finding a fault with the DD1 motor.

Although I never got an answer, I believe the brake being continuously applied through the pin not retracting with the hub caused the autopilot to be stressed and exert such forces that eventually shear the bolts and bend the link rod.

A couple of conclusions:

Check your break hub and ensure the pin is secured to the hub

Remember the Jefa DD1 exerts enormous forces that will tear itself from its holding down bolts.

Happy with how Jefa Steering (Stig) dealt with the problem


H385 #317 2014 Tivat Montenegro
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Ian2019 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ian2019 Quote  Post ReplyReply Direct Link To This Post Posted: 29 October 2020 at 19:49
Not sure how the photos got added at the beggining????
H385 #317 2014 Tivat Montenegro
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Captain Cook View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Captain Cook Quote  Post ReplyReply Direct Link To This Post Posted: 29 October 2020 at 20:21
The photos will be inserted where the cursor is located.
In your photo it is evident, that the draglink is deformed. Suppose you changed it.
The cables to the DD1 should be placed so water can not run down the cables in either direction.
Since the DD1 is placed where water may ingress, I have sealed all places where water may find a way to enter the drive, and I have shortened the cables and put them in a thin transparent tube, which also is sealed. Judged by your photos, water is no stranger to your DD1, so for future protection it may be an idea to seal the drive. On the sticker on the drive is a drawing which tells you that high-pressure washer is not allowed.
If you use the search function, you can find several members who had problems with water and rust inside the drive. As I recall, Jefa recommends to install the DD1 in a dry place.
Freya H400 #27 (2006), 40HP 3JH4E, 2-cabin, 3-blade Flexofold, Aries LiftUp Windvane, Exturn 300, Jefa DD1,Simrad NX40,Icom M603(VHF)+M802(SSB)
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Ian2019 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ian2019 Quote  Post ReplyReply Direct Link To This Post Posted: 29 October 2020 at 21:36
Hi thanks for your comments, and sure jefa replaced the draglink and other parts. The photos were taken after the inital investigation on the wiring loom. The wires were initialy contained in the black tube on the right. On the 385 I would have thought the autopilot would not normally be subject to any water as "pressure washing" or even any amount of water apart from washing down water unless the yacht was pooped. Unfortunately we have no dicision on the position of the autopilot as this is in the hands of Hanse during design which i supose has decided this to be a dry place. The wiring loom which was tested by several electronics personel showed no sign of corrosion, however I have shortend the cables for the new unit.
My point was for people to check that the pin in the break hubs were securely attached, as this i believe was the cause of the inital problem.
Also thanks, I'll have to check on where the cursor is in future.
Regards     
H385 #317 2014 Tivat Montenegro
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