Self Steering 'Grunting'

[MagicalArmchair]

Lewmar have changed the bearings and put the whole unit back together, and sent it back for a cost of £100, which is reasonable... they say they have bench tested it and it works however due to the state of the clutch they didn't load test it for fear of damaging it.

Two questions, when I have taken the unit out of the box, I note the sprocket does NOT turn freely. Its jammed as if the clutch is on (in much the same state as I sent it). I spoke to Lewmar and they said this is perfectly fine and expected as you have far more leverage on the wheel. Did your sprocket turn freely with the clutch disengaged? When you had it off the boat? Or did it have more resistance than you could turn by hand?

Supposing this is working, and as Lewmar suggest, can just be slotted back on to the boat, how would I best be minded to test the clutch? Go sailing in 25 knots, in full rig make sure she holds firm under autopilot against the weather helm?

[geoff]

From my less than perfect memory I shimmed it out until I could turn it by hand, then applied power to ensure that it worked. The shim ,which was just a paper gasket was only about 5thou I think. As to a test yours sounds fine if a bit brutal. Geoff

[MagicalArmchair]

I fitted the drive unit back to the boat to test my theory that it would lock the wheel... and nope it’s absolutely fine. Even though I can’t the shaft by hand off the boat, by hand the wheel still turns smoothly, perhaps with a little more resistance, but nothing perceptible.

I didn’t get a chance to test it and wire it back up as I was on my lunch break so I didn’t have much time. I’ll try and pop down tomorrow to finish the fitting and testing.

Good news though!!

[MagicalArmchair]

To finish this slightly bonkers story off, I went down to the boat and tried to tighten up the chain and wire it up... to my surprise it no longer fitted into the recess where the drive unit came from. Lewmar had put the thing together backwards!! 

This was how it arrived from Lewmar.



This was how it was before it went to our friends at Lewmar.



So back it came to the bat cave and I relished the opportunity to open it up and have a poke around inside. All the bearings are now replaced and look wonderful and it is exceedingly clean inside. They have done away with the need for a shim by removing material from the friction plate - which is a cracking idea and works wonderfully.





After reassembling and putting threadlocker on the machine screws, it's all back together and installed on the boat. In the marina, at least, it pulls incredibly well - yanking the wheel out of my hand quietly and efficiently.

So all's well that ends well. Whilst Lewmar would not warranty the drive unit, the work the engineer has done inside (albeit putting it together the wrong way around) is truly top notch and the repair, for a mere £100 is epic and I think it will last well. Thanks for all the input, that is hopefully another job ticked off.

[MagicalArmchair]

After wiring it up, I tested that the clutch engages and disengages in the berth, and it gripped really well. So, I thought I had cracked it.

We set off on our first summer cruise yesterday, the weather had not been kind enough to give me a chance to shakedown sail with the "fixed" drive unit. On setting off, I pressed the auto button on the ST6001 and the autopilot steered hard to port, I tried again, and again, it steered hard to port. 10 hours on the helm later, we arrived 😂, with aching feet. It wasn't easy managing all four kids without the autopilot, I can say.

Could I have wired it up the wrong way? Could it be the fluxgate compass? Seems a bit of a coincidence as that was working pre the drive unit .

[Yngmar]

Turn the boat in a circle - if the compass reading on the autopilot unit roughly follows the magnetic steering compass, the fluxgate is working okay. Ours didn't on the first sail last year - the reading never changed more than 10 degrees during this exercise.

Upon inspecting the fluxgate compass, the gimbal was stuck. I cleaned it and applied fresh grease and it's been working fince ever since.

Might also be caused by magnetic interference, so check around the fluxgate compass location with a handbearing compass for strange deflections before taking anything apart.

We usually do a basic test of our autopilot before setting off by engaging it, trying to turn the wheel by hand (to make sure the clutch grips) and then pushing +10/-10 buttons to see if it turns the wheel both ways. Would recommend adopting this practice at least after doing work on the system. Also a good idea to look at the compass heading and see if it's approximately right

[geoff]

Wireing up the motor connections the wrong way round would do the same , go on ask me how I know !. The +10_10 test should be a good indicator. Geoff

[MagicalArmchair]

What wonderful human beings you are! There was our dinghy pump motor near the flux gate... plus I had wired the pancake motor up the wrong way .

Stupidly I had assumed I could only test the autopilot whilst underway and we had a heading over ground - but it’s not working off that of course, it’s working from the compass. .

It now works on the berth - the next trip in our little adventure will tell all. Thanks for the help.

[Vasco]

Gentleman, a very helpful project documentation for this key part of blue water sailing. Thanks for fotos and thoughts.

As our drive, a DU145 is laying partly stripped on my workbench, I found the plastic planetary gearbox to be replaced.
Some cracks in the bushes of the axles of the planetary wheels are visible. Another Bavaria 40 Ocean found this plastic parts completely broken.

Is there any source known, where to buy this plastic gears as spare part? Up to now I was not able to find something in the internet.
Thanks for any reply.

Jens
SY Skokie

[MagicalArmchair]

Cliff from here https://yachtsteeringservices.com/ is quite frankly awesome and will have all the answers you will ever need.

He saved me thousands and is a top chap.

Good luck and take many, many photos please!!