24 June 2001 - The Engines (in bits)
RRS James Clark Ross Diary
Oh no my TV still doesn't work !
This seemed to be the biggest cry heard on board the ship in the evenings (from the very small number amongst us that
are able to take time to watch the TV !!) Even after we finally got out of the dry-dock we were still having problems
getting the mythical perfect picture. Even blaming the cranes,
the dock itself, the Radio Officer and everything in-between didn't solve the problem. However, there are
more important things to report this week !
This week has involved being invaded by lots of contractors who have been stripping down two of the Main Engines and lots of other bits but I will let the Chief Engineer explain more...
The engineering side of the refit
written by Duncan Anderson. Chief Engineer
RRS James Clark Ross has four Wartsila Vasa main engines: two 8 cylinder R32 big’uns each of 3.1 MW output and two 6 cylinder R22 little’uns each of 1MW output.
These engines are serviced by ship’s staff throughout the year, but are overhauled by Contractors whilst in the UK and subjected to regular "M.O.T’s" by Lloyds Surveyors. Each engine is overhauled every two years (8000 running hours) and surveyed every four years (reduced for convenience from the required five years) so that two engines are done each year. Engines number 2 and 3 being this year’s engines for overhaul, with number 3 also being surveyed.
The overhauls involve stripping out the cylinder heads, piston and conrod assemblies and cylinder liners and sending them to workshops ashore for cleaning, testing and renewal of worn parts etc. Also sent ashore are a number of ancillary items such as pumps, coolers and the turbocharger rotors. The latter are also dynamically balanced in a similar fashion to car wheels, although they are rather more critical as they revolve at around 20,000 rpm on the R32 or 40,000 rpm in the case of the R22.
As our engines run on a fuel similar to that burned in diesel car engines, they are relatively clean (most large marine engines run on thick tarry residual fuels commonly referred to as Heavy Oil) but the pictures show that, despite the best efforts of the contractors, the work inevitably leads to a good deal of disruption and muck spreading. This is countered by Angus and Dave, our two Motormen, who do their best to keep the engine room clean and tidy in the face of intense provocation !
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Angus Macaskill and Dave Bretland, |
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Once the various components have been overhauled, and the Surveyor has satisfied himself that they will continue to give safe and reliable service, they will be returned to the ship and refitted.
There are also a number of other jobs being carried out by our contractors; principally the renewal of the resilient mounts and flexible couplings on the two R22 engines. The reason for this rests with the nature of the ship’s work: as a multi-disciplinary oceanographic research vessel, the level of noise radiated into the water must be kept to a minimum to avoid disrupting the acoustic signals commonly used when carrying out scientific research.
The principal way of attenuating noise is to mount all the major items of machinery on resilient (rubber) mounts, thus isolating them from direct contact with the ship’s structure but necessitating the use of flexible couplings between the main engines and the generators that they drive. Both the mounts and the couplings have a finite life, and after ten years of hard work, they are degrading, so we are embarking on a programme of renewing them. To do this, the engines are jacked up a little, the old mounts removed, and the new ones slid into place and tightened down. This affects the height of the engine relative to the generator so alignment checks have to be carried out both before and after unbolting the old coupling and replacing it with the new.
Finally, after checking everything carefully, the engines will be started up and run on test. If all is well, then they will be run in with a programme of gradual power increases to ensure the best possible operation over the two years before their next overhaul.
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Number 2 engine minus cylinder heads |
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Removing a cylinder liner |
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And here are the vital statistics for the number 2 and number 3 engines.
Statistic | Number 2 (R32) | Number 3 (R22) |
Approx Running Hours From New | 39,000 | 36,000 |
Running Hours Between Overhauls | 8,000 (2 years) | 8,000 (2 years) |
Bore | 320 mm | 220 mm |
Stroke | 350 mm | 260 mm |
Engine Capacity | 225 litres | 59 litres |
Power Output | 3100 kW | 1000 kW |
Fuel Consumption at Full Power | 16100 l/day | 5400 l/day |
Engine Weight | 36.5 T | 9.3 T |
Overall Length | 6.1 m | 3.7 m |
Overall Height | 3.8 m | 2.5 m |
Overall Width | 2.0 m | 1.5 m |
A familiar sight but not at this end of the Atlantic.
This last week the RFA Grey Rover docked in the dry-dock that we had just come out of. Regular readers will know that
we see the Grey Rover quite often down in the Falkland Islands where she is normally based and so it was strange
to see her here on the Tyne where she is also undergoing a refit.
And Finally...
This last week saw a change over of Second Officers, with Andy Liddell leaving us after being here for a couple of weeks covering for our new 2/O, Ian Heffernan, who has just been promoted from being Third Officer on the RRS Ernest Shackleton. We would all just like to say thank-you to Andy for his hard work during the dry-dock and to wish him well at college later this year.
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Andy up the main mast |
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A view of RRS James Clark Ross from the rescue boat. |
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Coming up: This coming week we will be testing the lifeboats and the rescue boat, work continues on the main engines, the new LAN installation, and lots, lots more !
Written by Paul Clarke (Third officer)
