Tuesday, 27 January 2009

Brunel's steamships and the explosion of the Great Eastern.

One of the great things about the Internet is the amount and quality of the resources available. Many of these are of doubtful quality, but others are superb.

As readers may have guessed, I am fascinated by engineering, from the tiny (chip design) to the massive (ships, planes, etc). This means that a resource such as the archives of 'The Engineer' are so superb. The journal started in 1856, and is still being published.

In an 1859 issue a commentator goes into the steam explosion that killed six men on the first voyage of Isambard Kingdom Brunel's flawed masterpiece, the Great Eastern. The Great Eastern was the largest ship ever built when launched in 1858, and her size was only surpassed in 1899. I used to live on the Isle of Dogs in London, and near to my flat were massive hunks of timber that had once formed part of the slipway of this gigantic ship.

I had heard of this explosion, but had never read a first-hand account of it. Some of the language used in the report is fascinating. For example, the following description describes the design flaw that was the main cause of the disaster. Imagine it being read by an irate Victorian man; there is a certain magic to it that is rarely present in reports nowadays.
But we were told there was a safety-valve to this heater, and that the cock leading to it was shut. A cock leading to a safety-valve! an instrument which being ignorantly turned by a man could defeat the functions of the very device intended to circumvent the forgetfulness and unreliability of man! The very existence of such an arrangement was barbarous.
It continues, stating that there were other flaws:
Even had the most extraordinary vigilance been exercised, an ignorant stoker had it in his power, by the simple turning of a cock, to blow up the ship.
Basically, the explosion occurred because steam pressure built up in an enclosed space. That space had a safety valve, but before that there was also a stop-cock. Close the stop-cock, and the safety valve would not work, allowing pressure to build up. Other failures meant that even if the safety valve cock had been open, an explosion could have occurred at any time. It is strange that after 150 years reports on engineering failures often have the same tone: disbelief that the engineers had not thought of something that is obvious with hindsight.

Six men died in the accident. Brunel himself died from the effects of a stroke a few days later. The Great Eastern itself was a failure; it really only achieved success as a transatlantic cable layer. It was too grand a vision; it pushed the limits of engineering too far. Yet for those very reasons I will always have a soft spot for her.

Brunel had built two earlier great ships; the Great Western (1837) and the Great Britain (1843). All three ships were innovative; The Great Western was the first purpose-built transatlantic steamship; the Great Britain was the first ocean-going ship to have an iron hull and a screw propeller, it was also the largest vessel afloat when launched; and the Great Eastern was simply gigantic.

By a fantastic quirk of fate the Great Britain is still in existence. It spent 84 years as a hulk in the Falkland Islands before being brought back to the UK on a barge in 1970. It has now been cosmetically repaired, and sits magnificently in her original dry dock in Bristol. The award-winning museum is excellent, and is well worth a visit. The picture to the left shows her in her dry dock; it is difficult to get an image that adequately conveys her scale.

One of the fascinating things about the Great Britain is the way she was on the cusp of change; the change from wooden-hulled to iron-hulled ships; from sail to steam; and from paddle wheels to screw propeller. It took a visionary like Brunel to fit all of these together into one ship.

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