|Speedy Builder5||17/07/2019 16:26:27|
|1861 forum posts|
How to replace your crankshaft, when it weighs 7.5 tons and is in the engine room of an ocean liner.
|XD 351||17/07/2019 18:06:01|
1384 forum posts
What a PIA !
I will never complain about doing an engine change again !
From the video i noticed a few things :
The guys in white coats are the boffins - there to tell everyone how to do it and never get their hands dirty .
The guys in blue are there to stand around with their hands on their hips amd make silly comments - a low chance of them getting dirty as well
The guys in red do 95% of the work and are probably the lowest paid out of all of them all !
|Speedy Builder5||17/07/2019 18:16:58|
|1861 forum posts|
The guys in Red have White hats, the ones in White have Yellow hats, the guys in blue have Grey hair !
|Howard Lewis||17/07/2019 18:31:55|
|2581 forum posts|
But what a course in jacking and packing and then winching into place. But to within 1 mm (0.0393" )?
Makes changing the crank in a Triumph 2000, at the side of the road look easy!
A 7.5 ton shaft is small in the marine world. The crankshaft for 108,000 h p engines in the Emma Maersk and her sister ship weigh 300 tons. The Cylinder Head studs are 14 feet long!
2530 forum posts
Beg to differ; going back many years to when I was Marine engineer in the MN , ED & Blue Flue Co. the guys in white are the ships Senior engineers, the guys in blue would most likely be subcontractors or dock yard fitting techs, guys in red are the heavy lift guys brought in, the Philippine guys in light blue would be the ships mech tech /assistant engineers. I wore white overalls when on watch & nothing but skiddies underneath, it was hot down there in engine room, & I am not talking of todays remote controlled air conditioned ships either. Engines were Sulzer's, B&W or steam turbine driving small general cargo trade, 7 - 10 thousand gross tonnage.
|344 forum posts|
I thought we were a model engineering website! Only kidding only kidding...
Wow youd have thought they would have come up with a better way to get the thing indoors! All that chain blocking etc. Imagine if you dropped it?
Do they put the engine in while they are building it thus making access so tight. Wouldn't it be easier to just bung a short motor in rather than mess about with the crank?.
I cant begin to picture what Howard mentioned, a 300 ton crank? Golly!
Amazed of Barnsley
|Brian Oldford||18/07/2019 17:16:08|
596 forum posts
They put the crank in place and build the engine and ship around it.
16828 forum posts
Plasma, a few photos of a small crank being made here
|Howard Lewis||18/07/2019 17:42:22|
|2581 forum posts|
Look on Google for Emma Maersk. With a bit of luck there will be a link that takes you to the words and pictures about the engine.
Google "Emma Maersk engine".
The first picture that i saw was a what looked like a Dinky toy pulling a full size engine out of the erecting shop. It was a six wheeled Scania ballast tractor!
The engine is a turbocharged (and chargecooled ) two stroke, made under licence, from Wartsila-Sulzer. in Korea. The dimensions are almost beyond belief. 108,000 hp at 102 rpm. The tank top below the crank is 9 feet deep. The main bearing saddles have ladder rungs cast into them. Around the propellor shaft are magnets, With the field coils energised, they can add about 4.5 Mw to the output, or unenergised, generate that much power for on board use.
The head studs are 14 feet long, to carry the clamp loads into the crankcase without risking distorting the cylinder liners.
A friend witnessed one of the auxiliary engines having the crankshaft reground in situ. This was a small unit, only about 12 feet high overall!
Truly, an awesome unit!
Main propulsion engines for ships of this size are a breed apart from anything that we mere landlubbers ever see.
Edited By Howard Lewis on 18/07/2019 17:44:50
|Clive Hartland||18/07/2019 18:09:11|
2491 forum posts
My Son was a Blue water engineer, and served on a granite chip boat that worked between Ireland and Rochester and occasionally to Spain, one trip to Spain was trouble. As they approached santander the engine bent a con rod and they were stuck about 5 miles out of the Port. The captain ordered the anchor dropped but it ran out all the chain and still did not hit bottom.
To save salvage charges he called the pilot boat and they were pulled in slowly, but of course the anchor chain ! The winch could not lift the anchor wieght and chain so they had to cut it away.
Once in harbour my Son checked the engine and removed the offennding con rod by tying it up out of the way. The journel, he put a sealing bandage around it and used big Jubillee clips to hold and then obtained permission from Lloyds insurance to run the engine in that condition but at 5 knots only.
They came back to Rochester and parked up alongside the Harbour on the Chatham dockyard by a crane.
Called in the heavy brigade who proceeded to lift the crankcase off the engine bed to expose the crankshaft. By then they had cut a large aperture in the bulkhead to lift through the old crankshaft. A new one from Doxford arrived. But, the straight edge suggested that the engine base was distorted, This is where I came in with an optical device (Auto Collimator) that I could measure the deviation of the bed. I did this and found that in fact the bed was 278 thou. down at each end and about 170 in the middle. This meant they needed a new engine bed.
It duly arrived and was via the crane lifted down and through the hole in the bulkhead and set down in place of the damaged one. Then the new crank was fitted and crankcase bedded down and all was well. To my knowlede the bed and old crankshaft are still there on the dockside.
The boat was leased to a chap but the Insurance paid up and he lost his lease and the owners wanted him to work as a Night security till it was paid off what they paid the heavy gang, needless to say my Son upped and went to Norway to work on the boats from an Under water gas and oil survey company. He is now their Logistics and trouble shooter in Houston in Texas.
|Nigel Graham 2||28/07/2019 18:14:24|
|452 forum posts|
Thank you for that Doxford album, Jason.
It's good that its compilers have named the personnel where possible: it's all too easy to look at some magnificent piece of engineering and the machinery needed to make it and forget those machines are useless without skilled people to operate them. That still stands: the production operator simply feeding an NC machine-tool with stock billets need not necessarily understand its programming or indeed the machining, but someone has to.
Looking at those pictures reminds me of something a retired engineering manager told me. He was a former Commissioning Engineer (I think that was his title) for UKAEA, and of course risen from fully apprentice-trained when management was a skill acquired to help support the shop-floor work.
A very large proportion of that work was one-off, including very large components made from costly, traceable-source materials; so a huge responsibility on the machinists. He told me sometimes a machinist was so nervous making the last few cuts he had to give the poor bloke the moral support of literally standing by him, verifying measurements and control settings.
As far as I understood it no-one thought any the worse of the machinist. The management needed the work completed to its very high specifications above all else, and if the turner or miller needed help, and perhaps took an hour extra as a result, that's far better than him losing his nerve and scrapping many thousands of £££ and many 10s of hours of work-piece by the finishing cut going wrong.
I knew the gentleman concerned as one of a pair of retired senior engineers, reprising their bench skills of long before by working a gentle 2 or 3 days a week on some of the stranger or fiddlier bits of metalwork involved in our employers' business of sub-contract electronics for MoD and other Government establishments - including occasionally the UKAEA.
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