It’s exactly a century today since the Titanic sank, and I’m interrupting my usual weekly worldbuilding series to mark the moment. Titanic has been capturing headlines in New Zealand this week with Kiwi archivist Lemuel Lyes’ discovery that the Titanic’s captain, Edward Smith, had been to Christchurch 22 years earlier, in command of the Coptic.
Lemuel is a regular commenter on this blog. And he’s made a fascinating discovery. Until recently New Zealand had a self-image of being historically isolated at the bottom of the South Pacific. But dig far enough – and we can usually find some connection, however small, with the world. Proof of the degree to which the world was globalised back then.
For me the Titanic generally reveals much about our perceptions of the past. Titanic wasn’t the only ship of her class. There were three – Olympic, Titanic and Britannic. Their careers were filled with drama – Olympic was involved in various collisions and helped rescue crew from HMS Audacious in 1914. My great uncle was a witness that day - more on that another time. Britannic went down in almost identical way to her sister ship. Yet only Titanic has captured our imagination; it has become a metaphor for failing to face up to the facts – fixing things by ’rearranging the deck chairs on the Titanic’. And that night to remember has itself been mythologised; such as the irony of being labelled ‘unsinkable’ and then sinking. It is ironic; but not because the ship was thought to be unsinkable – it was a marketing slogan.
A quick dip into geekery. The three liners differed in detail but were built around one design, and had more internal subdivision than earlier vessels. Ships sink in two ways: (a) loss of reserve buoyancy, and (b) loss of reserve stability from asymmetric flooding (more complex than it sounds – it also relates to metacentric height) – the ship rolls over or sinks by one end. Capsizing also happens if reserve stability is still good, via free-surface effects (‘slopping)’. That’s what sank Wahine in Wellington harbour, 44 years ago this month and the Herald of Free Enterprise off Zeebrugge in 1987, among others.
Both Olympic and Titanic were designed to stay afloat if two compartments were flooded – and Olympic did so, when she collided with HMS Hawke in 1911. They could also float if four forward compartments were flooded.But it was a flawed design. The transverse bulkheads extended only to B-deck, not far above load waterline, and were open at the top. Once the ship was down even slightly by the head, water could spill between them. On Titanic, spill-over began within 20 minutes of the collision with the iceberg. This made it impossible to establish flooding boundaries and hastened the sinking. She would have sunk anyway; a recent study has shown that the collision caused structural failure of the hull plating across six compartments. The damage was compounded by faulty steel; the plates were not ductile, and in low temperatures the rivets were brittle and suffered shear failure. However, if the bulkheads had been of effective height, the ship would not have sunk so quickly – and lives could have been saved.
The more interesting story for me is the loss of Britannic. After the disaster, Olympic was modified to improve the subdivision, extend the double bottom into a double hull, and add more lifeboats. These features were then built into the third of the trio, RMS Britannic. She was a shade larger than Titanic, launched in 1914 and still fitting out at Harland and Wolff when the First World War broke out. Yet despite the improvements, she sank in exactly the same way as Titanic. This time it wasn’t an iceberg – it was a German weapon. She was requisitioned as a hospital ship and sent to the Mediterranean. And in the early hours of 21 November 1916, while off the island of Kea, she either hit a mine or was torpedoed. The weapon struck at a junction between two watertight compartments and shock response damaged the watertight doors elsewhere.
At first the ship seemed likely to survive. However, the loss of reserve buoyancy and resulting sinkage left some rows of scuttles underwater; and they had been left open by the nurses to give the patients air. Britannic began to settle rapidly by the head – much faster than Titanic. Captain Bartlett ordered the ship driven for the shore, hoping to beach her; but this may have hastened the rate of water ingress. She went down just 55 minutes after the explosion. Fortunately the water was warm and there were plenty of lifeboats; of the 1066 people on board just thirty died. It could have been far worse.
Which brings me to the weirdest thing. One of the survivors was Violet Jessup – who had also been on board Olympic when she collided with HMS Hawke – and the Titanic, when she sank. Jessup survived all three catastrophes. Either very bad luck – or very good. I can’t tell which…
Copyright © Matthew Wright 2012