Author Topic: Mirage returns! 34 hour passage complete, however...  (Read 2462 times)

MagicalArmchair

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Yesterday morning at 5:30AM we set off from Ocean Marina Village in Southampton and arrived at midday today after a long, overnight chug, with only a few opportunities to sail (boo). At least the boat is back in Chatham Marina! Success! A few things came up in this, most prolonged, shakedown. I was hoping someone could point me in the correct direction.

  • The self steering "grunts" when the Raymarine autopilot steers to starboard - it vibrates the floor a little, and feels like something is slipping - its only when turning to starboard - when it turns to port it is silent. It still works perfectly well and holds a course.
  • The flux gate compass got stuck... I think. One of my crew noticed that the autopilot was 50 degrees out from the compass on its heading. When I looked at the e7, the boat looked like it was going sideways through the water! I checked and the autopilot was working fine, just at 50 degrees out!... early in the evening, the autopilot suddenly swung us around 50 degrees to starboard... it had got unstuck and now matched the compass! Anyone had this?
  • The steering feels noticeably stiff.
  • The gas ran out! The boat has the original regulator (eek) - I went to swap the bottle over and as I started to tighten it up, before it got tight, it started spewing gas everywhere. I retreated and unscrewed the regulator. Faulty gas bottle or regulator do we think?

Yngmar

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #1 on: August 08 2020, 18:51 »
1) If it's the chain driving the wheel axle type, check chain tension - it might be slipping/jumping if very lose. Easy to adjust, the drive is mounted in slots and you just drop it down until chain is tensioned and do the bolts back up. Might be the bolts are just loosened.

2) Yep, had that exact same. Stripped the compass, lubricated the gimbal needle bearings and it never did it again. Might also be magnetic interference though, so check with the hand-bearing compass that you do not have any interference around the fluxgate compass first - as that's quicker than stripping it down!

3) Stiff steering might be anything. Helps to disconnect steering cables and see if it's the rudder (bearings are common, search forum) or the wheel/cable part. Use emergency tiller to check rudder resistance while cables are disconnected.

4) It's normal for camping gaz bottles to leak a bit as the valve is being screwed in the bottle. Should stop when it's tightened down though. Also the valve should be closed when swapping bottles. The original regulator is definitely due for a replacement though! :) SVB has the one that fits the locker _and_ has a pressure gauge which doubles as leak tester.
Sailing Songbird  ⛵️ Bavaria 40 Ocean (2001)

Mirror45184

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #2 on: August 08 2020, 22:36 »
In respect to the Fluxgate compass:
1. check the location of the sensor and make sure that it is not near anything metallic or wiring. About 300 to 500 mm clearance is needed.
2. Go through the vessel and turn items on and off and note if there is any change to the compass.
They can be sensitive things!
Mark Hutton
SV SYnergy
B40 Cruiser 2009

Rampage

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #3 on: August 09 2020, 10:06 »
Autopilot: what type of drive do you have? Is it the rotary type in the binnacle or a linear drive in the tiller flat?  Given that the steering is tight or stiff, check that the coupling of the drive to the steering is properly fitted and connected.  If something’s worked loose, it could be giving the sort of problems you’re getting.  Also check the rudder reference unit, as that could be contributing to the grunting or chattering.

Fluxgate compass: good suggestions about lubing the gimbals and making sure there’s no metal in the area.  Before you do take it to bits, check the wiring.  I’ve had similar weird compass readings which I tracked down to some poor connections in the compass wiring.  Remade the connections, ensured that they were well supported and not had any subsequent problems.

Camping Gaz: once you’ve got the reg threads engaged, I pick the assembly up by the regulator and spin the bottle on quickly.  Always releases some gas as it goes home but by spinning the bottle, it gets the job done quickly with minimum leakage.

MagicalArmchair

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #4 on: August 09 2020, 19:35 »
Thank you all!

  • Self Steering grunts: Thank you, I must admit I have poked my head into the lazarette and I have no idea about what I am looking at  ;D. I will investigate the Raymarine Type 150/400 Autopilot system, read all the documentation I can find, and then try your suggested fixes.
  • Fluxgate compass sticking: Its interesting the boat continued to steer under autopilot - if it was completely stuck, you would think it wouldn't work at all? Meaning interference is more likely I guess? I'll find the compass (its in the bilge) and see if I can remember what was in its vicinity at the time it went a bit crazy.
  • Steering stiff: How do you disconnect the steering cables? Are there any documents here about the steering system on these Bavaria's I can study? Does anyone have a photo of the top bearings I can oil? What do you oil/grease them with?
  • Regulator: Ah! The old regulator on my old boat never leaked that much when I changed it and that was a cheapo camping one to my shame (I had that on her for ten years too, oops). Is this the right guy? https://www.svb24.com/en/gok-gas-pressure-regulator-50-mbar-marine-angled.html

Rampage

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #5 on: August 10 2020, 10:07 »
Regulator: the one you linked to isn%u2019t what you want: it%u2019s designed to fit onto a tap which is then fitted onto the cylinder.  This one from Force4 is what you want https://www.force4.co.uk/item/Force-4/Camping-Gas-Regulator/DY2.  Bit cheaper too.....

Steering stiff: sorry to be obvious, but you have fully slackened the brake off?  It%u2019s the boss in the centre of the steering wheel.  I know to my cost that it%u2019s easy to forget to slacken it off enough.  As to the steering system itself, I%u2019m not sure which system is fitted to the centre cockpit Bavarias but I assume its cable steering.  There%u2019ll probably be a couple of bearings in the steering wheel shaft in the top of the binnacle, two pulleys in the base of the binnacle to make the turn towards the stern, a straight run via a couple guiding pulleys to the quadrant on the rudder shaft.  Minimal friction in that set up and not much to mess with.
Check that the nut on the top of the rudder post isn%u2019t over tight and that%u2019s about it without taking the boat out of the water and checking the rudder bearings.
Compass: providing that the compass is outputting something resembling a bearing signal, then the autopilot will follow it....  Its only when the compass isn%u2019t putting out a signal that the autopilot will sulk and refuse to do anything.

Don%u2019t know what%u2019s going on with the font!

MagicalArmchair

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #6 on: August 10 2020, 12:49 »
Thanks Rampage

Steering stiff: I didn't know that boss was a break, so not so obvious!!! I wonder if it's that?? That would be nice if that was the case - that would make the self steering work hard too also and might explain the "grunting"!

Regulator: That's the guy I had on my old boat :). So that fits nicely into the locker also? I could do with saving some pennies after that epic two day chug...

Symphony

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #7 on: August 10 2020, 21:41 »
The steering system is standard Whitlock/Lewmar with a chain over a sprocket on the wheel shaft attached to 2 cables that go over sheaves at the bottom of the pedestal and then to the quadrant on the rudder stock. simple and reliable. You can find the schematic of the layout on the Lewmar site. The wheel brake is the white knob on the end of the shaft in the wheel boss. It screws into the locking nut and applies pressure as you tighten it to slowly lock the wheel on the shaft. Usual to lock off when boat is stationary to stop the rudder turning. As it is a friction brake sometimes useful to apply some pressure to limit movement for example to help hold a course when you don't want to engage the autopilot.  When using the autopilot it should be freed right off and the wheel should spin freely.

Autopilot drive can be either a Raymarine ram working on the steering quadrant or a Lewmar drive motor at the bottom of the binnacle with a chain driving the wheel shaft. Look in the lazarette will soon identify if it is a ram and through the inspection hatch in the aft cabin under the binnacle for the Lewmar drive.

MagicalArmchair

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #8 on: August 12 2020, 09:55 »
Thanks Symphony, I'm popping down at lunchtime today (now she is finally local!), so I will take some photos and check then!

MagicalArmchair

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Re: Mirage returns! 34 hour passage complete, however...
« Reply #9 on: August 12 2020, 14:05 »
Once the boss was fully loose, the whole steering was wonderful and slick ....  ::) :o

Thanks for the assist and for pointing out the obvious. I suggest the poor self steering gear will now no longer grunt also!!