Tuesday, December 19, 2017

The latest HMS Queen Elizabeth story



HMS Queen Elizabeth, the navy's new carrier, has been undergoing her sea trials.

The purpose of sea trials is to deliberately put the hull and sailing systems of a new ship under extreme pressure to try to find faults so you can fix them before putting the ship into normal service.  It is most unusual not to find any minor faults at this stage. Sure enough, there have been one or two comparatively minor issues. According to a Royal Navy spokesman,


“An issue with a shaft seal has been identified during HMS Queen Elizabeth’s sea trials; this is scheduled for repair while she is alongside at Portsmouth. It does not prevent her from sailing again and her sea trials programme will not be affected.”
Needless to say the assorted hacks of various British newspapers have had a field day with this.

According to The Sun newspaper,

“A faulty seal around one of the vast warship’s propeller shafts means 200 litres of sea water pour in every hour.”

Let's put that into context, shall we? As the UK Defence journal points out in a good article here, 200 litres is a couple of bathtubs' worth of water.

I don't know how much water the taps in the bathrooms of Sun, Mail or Express journalists deliver, but the taps in the bath in my house could fill it a lot more than twice in an hour.  So if the Sun figures are accurate, this leak is rather less powerful than the flow from the taps of a typical bath. By my calculations that flow of water would take of the order of magnitude of perhaps three months to deliver water equivalent to one percent of HMS Queen Elizabeth's 60,000 tonne displacement - that's if all her pumps had stopped working.

The pumps on a typical narrow boat on Britain's canals such as you might hire to take your family for a week's holiday, by the way, can handle a thousand litres an hour. The navy says that the carrier's pumps are clearing this relatively trivial flow of water with no difficulty and despite what one or two egregiously ill-informed hacks have written, she certainly isn't sinking.

There is a good comparison between the issues found to date on the Queen Elizabeth's sea trials and those of previous RN ships and of other navies on the "Thin pinstriped line" blog here.

Admiral Chris Parry told Sky News the leak was a non-issue:
“Every ship, to tell you the truth, takes on water that’s why you have pumps. What people have to realise is the whole reason for sea trials is that you race and rally the ship, you stress it right to its extremes, and you’re really looking for faults like this to see what happens.

You get this all the time, you’ve got very complicated engineering under the water, it’s operating obviously at sea and every yachtsman will tell you they take in water somewhere, that’s what you’ve got pumps for, that’s why you have dedicated engineers, it really is no big deal I have to tell you.”

Don't get me started on all the rubbish written about whether these carriers will have jet aircraft when they are fully operational. Of course they will.

It does rather make me wonder why Vladimir Putin bothers to waste millions of roubles extracted from Russian taxpayers on running the RT and Sputnik "news channels" to denigrate the United Kingdom. Some of our own journalists are doing a far more effective job and he doesn't have to pay them.

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