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Sunday 15 January 2012

So called experts

Save us from them.

I refer in this case to the Costa Concordia incident. I’m no expert on diesel electric propulsion but I have had extensive service on ships with that system.

Last night Malcolm Latarche, editor of the global shipping magazine IHS Fairplay Solutions, said the problem may have been caused by a phenomenon known as 'harmonic interference'.

If the vessel was travelling at cruising speed it is unlikely to have suffered this effect. This is normally applicable at low powers and is usually designed out at build. Additional safeguards are that harmonic filters are employed to negate any transient lower power risks. On my last ship we had two. One in use and another as back up.

This next paragraph makes no sense either.

The expert said the harmonic interference – a type of power surge – could have caused a malfunction in the generators feeding the ship's six diesel electric engines with which the back-up systems could not cope.

What are these generators that feed the diesel electric engines? What are the generators that supply the diesel generators? Where do they get their power from? Doesn’t make sense.

A diesel electric propulsion system consists of multiple diesel engines synchronised together. Each engine drives a generator supplying  AC at say 6.6kV (Alternating current) to a synchroconverter which converts the AC to DC (Direct current) to drive the propulsion motors.

This would have caused the ship to lose navigational power and steering control and veer off course, he said.

Again this is mere guesswork. Bearing in mind that  fifty per cent of the steering motors are fed from the emergency switchboard, I feel this is mere supposition. If power to the emergency switchboard is lost, an emergency generator, well away from the main machinery spaces, will automatically start and within sixty seconds be supplying the steering motors.

And

Mr Latarche added: 'Although the damage caused to the ship was severe, there are many safeguards in the design of a state-of-the-art cruise ship to prevent it turning over.

'There is a second hull within the outer hull. Inside the inner hull there is a steel structure like an ice tray to contain the water and prevent it spreading through the ship.

This intrigues me. As far as I know the only vessels required to be double skinned are oil tankers.

Before I retired we had just built four landing ships which were classified A1 at Lloyds register of shipping, which is the maximum possible certification standard. They did not have a double skin.

Much has been said of the evacuation of the vessel. In my opinion it is an almost impossible task to evacuate people who have no idea about the procedure involved. I’ve done various courses involving lifeboats and evacuation systems and realise that even those trained would find it difficult to escape given these particular circumstances.

I’m heartened to here that the number of missing is now down to 15, and that voices have been heard within the hull.

My condolence's go out to the bereaved. 

10 comments:

  1. Too true FE. l've served on these type of vessels and all these so called 'experts' haven't a bloody clue. One wonders if the MSM actively avoid anyone talking commonsense and actual facts.

    Also l'm sick of 'it was just like the Titanic' quoted.

    Errr no, it bloody wasn't!

    There was even one saying lifeboats should be designed to cope with emergencies like this. FFS, how???

    Apart from that you have the starboard side with all the pax crushed against the rails and the port side with now a steel wall (formerly the deck) to negotiate.

    God give me strength!

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  2. You've discovered an aspect of the media I've commented on before. That is, there are two possible types of subject that the media can comment on - those that you personally know something about, and those that you don't.

    Whenever they comment on a subject that you know something about, that comment is universally naive, misguided, and (as a result) plain wrong. Whenever they comment on a subject that you don't know about, we take their comment as informative because we don't have any means of challenging it.

    I've noticed this (repeatedly) with the subject of intellectual property. You've noticed it with shipbuilding. Everyone I've explained this analysis to has agreed that they have noticed it in their specialist subject.

    Conclusion: the media are a bunch of morons.

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  3. "Conclusion: the media are a bunch of morons" ...

    They're also a bunch of sharks, in that they'll say or publish anything in an attempt to outsell their rivals .. secure in the knowledge that they can correct any misreporting at a later date, as "new evidence" comes to light ..

    FE .. I was under the impression (possibly mistaken) that LPG Carriers were also required to be double-hulled ..

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  4. I would like someone opposite thinking. Thanks for sharing your precious comprehension here.

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  5. Ancient +Tattered Airman16 January 2012 at 11:57

    I hope this post is not thought out of place but hopefully shows the thinking of the times we find ourselves living in:



    Ineptocracy (in-ep-toc'-ra-cy) - a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

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  6. I smelt bullshit as soon as I read the bit about generators feeding engines. I assume this vessel has conventional rear facing propellers and rudder(s)? I can't see any evidence of steerable "Pods" that now seem to be the norm?

    The Wiki page says it has 6 Wartsila diesels totalling 110,000 hp (or at least I guess it's a total - 660,000 hp would turn it into a speedboat..) Surely there would be sufficient redundancy that any one of these would be able to provide limited propulsion and steering?

    Would the main propulsion motors really be DC? I thought that variable frequency inverter driven AC motors are the normal method? This is commonplace in smaller industrial settings, with the AC-DC-AC conversion being done in a self contained control box.

    @ CH - don't LPG tankers have a number of separate, spherical gas tanks? So long as these aren't part of the hull I would have thought this could be considered as a "double" skin?

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  7. I suspect the ship capsized because it drifted (or was steered) into shallow water; wouldn't have been enough to keep the thing afloat.

    As "Smoking" says, the Titanic references are just lazy thinking. On seeing the photos in the Sundays papers I immediately thought "Herald of Free Enterprise" even though cause for wreck is apparently different.

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  8. I must admit that while I do not know the cause of the initial problem I was concerned by the descriptions of the initial list followed by a sharper move in the opposite direction (to Starboard). My initial feelings were that this was "loll" as opposed to "list" and is highly dangerous as the ship will become extremely unstable. Of course, there may be more serious damage to the submerged starboard side but these floating gin palaces do appear to have very high upperworks and even a slight heel will make escape much more difficult. The SOLAS idea that these ships can remain afloat and even return to port having sustained major damage is one that I feel needs logging in the "You are joking!" category.
    TTFN :)

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  9. Hello FE.
    If the ship had a DP2 cert all the steering motors (azimuths) would be form the 440V(?) board which should have been split.
    If the common busbar was closed and a problem developed....
    Well you see what I am getting at?
    Just a different angle, my ship has this set up.

    Rgds.

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  10. Lloyds A1 is the highest possible standard?

    So what happened to 100+A1 or whatever it was the Campers were always claiming for their craft?

    Did it never exist? Was it all a yacht-broker's fantasy?

    Signed,

    Disappointed of Goldhanger

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