Engine overspeed, gearbox catastrophic failure

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Engine overspeed, gearbox catastrophic failure

Postby JK » Tue Feb 27, 2018 7:26 am

Wow, oh wow! They were some frikken lucky going by this article. Off to find the report.

http://thechronicleherald.ca/business/1 ... ss_insider

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Re: Engine overspeed, gearbox catastrophic failure

Postby JK » Tue Feb 27, 2018 7:30 am

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Re: Engine overspeed, gearbox catastrophic failure

Postby Merlyn » Thu Mar 01, 2018 5:22 am

Interesting article, I see this trawler had the same size crew as a Supertanker / large container ship, hot bunking or what.
Been on those factory ships and trawlers, stinkers jobbies or what.
I see it had a 9 buckets in line Maggie Deutz engine fitted with possibly an in line Bosch injection pump.
We call them Maggie Deutz as over here we can't pronounce Magirus Deutz properly so throught history they have always been referred to as Maggie Deutz.
I well remember those big old aircooled engines with all that trunking rattling and going to trunk the blown air around the engine.
Reading the reports I see that once again the sharp piece of string enters into the equation re engineering and I do hope Andrew/ Felix reads this as owing to the damage done by this particular sharp piece of string he may require to modify his Nodding Donkey Engine design powered by yet another sharp piece of string.
I presume this pump to be a Bosch mechanical inline pump ( some have a Chinese version fitted ) and obviously non CR set up.
Seems from the reports that this engine had an ongoing cutting out problem going way back which for some reason was never resolved.
It was however discovered that by giving it full throttle on the pump obviously to get the plunger helixes in their maximum pumping positions that by max. fueling it ( with or without a cold start excess fueling device engaged ) and turning it over off she went.
By closely controlling the situation on the pump arm you would apon the engine firing immediately release the arm and the governor compression coil spring would take over and prevent the engine over speeding it's governed top RPM.
However with a " wrench " on the spindle together with a deckhand on the end of a rope without any unsupervised knowledgeable hand immediately present a recipe for a major disaster was created as obviously the deckhand being told to pull on the rope did just that, maintain a constant pull on the rope.
Engine comes in possibly on one or two to start with, the rack bar is set to max. and in come all 9 buckets in line and the coil spring on the rack bar to governor mechanism does its job and closes up the coils in a desperate attempt to pull the rack bar back in order to prevent the engine exceeding its top governed RPM.
However the deckhand not being aware of any of this maintains his pulling of the rope thus defeating the design aspect of the rack bar/ coilspring set up and as such overrides the governor and off goes the engine screaming way above its top governed RPM - and uncontrollable.
The CE hearing this in the control room reaches for the electrically operated stop control which does not work. ( not an uncommon occurrence, ( bad earth, center spindle partly seized, feed supply etc. )
Out of control the engine approaches the bouncy valves / rod out the side normal situation but It goes for exploding two ancillary drive units who decide to let go before throwing a rod or two out the side.
I see it clipped the inlet valves so if any valve heads came off it's in for a piston / liner / headchange / overhaul at least never mind the bottom ends.
I have seen broken compression springs on the rackbar to governor mechanism before and unless you can get the rackbar back PDQ to its helixes turned to the minimum fuel output setting its rods out the side nearly every time.
Sometimes the broken spring ends if jagged will remain loosely in place but you can on occasions hear the engine hunting on tick over like on some pumps if the oil is low in the sealed governed box hunting will occur on tickover.

So from where I am standing it's a H.E. jobby.
Human Error that is.
I suppose that a mitigating factor would be a faulty stop control but by closely monitoring the rackbar position none of the destruction would have happened and had this long standing cutting out defect been cured then the opportunity to self destruct would not have presented itself.
So conclusion?

Gold medal for the CE for not allowing the deck hand to cop red hot oil soaked pieces of casting ?
Demotion back to painting out the bilges?
Down the road?
Or the now normal course of events whereby massive court case for the CE V the owners re damages for not rectifying the long standing cutting out defect and allowing the CE to go to sea knowing that further cutting out might well re occur?

Or a mysterious no speaky clause massive payment in two years plus time for the CE so he can buy his own Scalloper boat and go up against his former employers?

So best Andrew rethink this sharp piece of string invention perhaps in view of all the foregoing maybe?

In writing I see the report mentions together with the rope a " wrench " was used.

Over here we have an adjustable spanner, stilsons and molegrips ( molies ) all of which would lend themselves to being attached to the governor spindle so which one is it in U.K. speak?

Molies with radiused Jaws would seem to be favorite.


Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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Re: Engine overspeed, gearbox catastrophic failure

Postby The Dieselduck » Sun Mar 11, 2018 3:48 pm

The saying, "if you think hiring a professional is expensive, try hiring an amateur", comes to mind
Martin Leduc
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