Wednesday, 18 December 2013

'UNSINKABLE' HULL.

The Mercury (Hobart, Tas. : 1860 - 1954) (about) Previous issueTuesday 3 August 1909

THE STEAMER WARATAH.
OVERDUE AT CAPETOWN.

LONDON, August 2.

"Reuter's correspondent at Durban
says there is alarm over the non-arrival
of the steamer Waratah at Cape Town."

"The vessel left Port Natal on July
26 with three hundred persons aboard (actually 211)."

"The Waratah is (optimistically in the present tense)
a large twin-screw steamer of nearly 10,000 tons,
and is the latest addition to Lund's Blue Anchor
line, trading between Australia, South
Africa, and London. She left Australia
in January last on her first homeward
voyage, and is now on her second, having
sailed from Sydney on June 26, Melbourne on July 1,
and Adelaide on July 7,
and having reached Durban on July 25."

"According to our cablegrams, she
left the last-mentioned port on July 26
for Cape Town, and as the distance is
only 856 miles, she should have arrived
there on July 29."

"The vessel is 480ft, long, 59ft. beam, and 39ft. deep,
and is built to Lloyd's highest class. The vessel
was most carefully designed for the
special requirements of the trade."

This comment is in sharp contrast to the 'observer' (a previous post) who claimed that the top hamper was not in keeping with the Waratah's trade requirements.

"She has two sets of quadruple expansion engines,
capable of maintaining a sea speed
of 13½ knots."

"The steamer is divided
into eight watertight compartments, and
there is a cellular double bottom extending
the full length of the hull, which, in
the opinion of experts, "rendered her
practically immune from any danger of
sinking."

The opinion of the experts gave everyone a false sense of security as was clearly demonstrated by the Titanic in 1912. The assumption was that a double hull or cellular double bottom with eight watertight compartments was impenetrable, and if so the watertight compartments would halt ingress of water.  The Titanic demonstrated that although the iceberg in effect only created a series of relatively small punctures in the hull, the brittle rivets and hull plates were vulnerable to cracking and snapping, allowing the rents to spread (due to the forces at play) in a zipper-like fashion along seams, across watertight compartments, causing general flooding and the vessel to founder. Similarly in the case of the Waratah damage sustained by taking the ground at Adelaide may have been initially a series of very small areas of compromise in the hull.  These in turn, subjected to forces, would spread into significance of catastrophic proportions.



an example of hull and rivets of the time - note damaged areas


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