Honouring Mallory’s research in identifying formation of abnormal waves
LAST week’s World War II story drew interesting responses from readers. Among them was Captain John Page who brought me notes written by the late Captain Professor John Mallory, a former cadet aboard the training ship General Botha in 1931.
When South Africa declared war on Germany in 1939, Second Mate Mallory was aboard the South African steamer Erica, discharging Philippine mahogany logs in Sydney.
The master, an Australian naval reservist, ordered that the ship should be painted in multi-coloured camouflage, and the entire ship’s company began the task.
Mallory wrote “We were all very proud of her appearance.”
From Sydney, Erica steamed to Melbourne, and then, while crossing the Great Australian Bight, the understandably anxious officer on watch observed another vessel closing the nine-knot Erica at high speed.
When she was about two nautical miles astern of Erica, the other ship suddenly turned, and steamed away.
Erica’s radio officer picked up a frantic signal from the other vessel – an Australian coastal passenger ship – to naval authorities. “Sighted German raider steaming westwards in position XYZ… ” an obvious reference to the weirdly-camouflaged Erica!
The South African vessel rounded Cape Leeuwin, Australia’s most south-westerly point, and entered Bunbury, a port south of Fremantle.
Like other South African railway steamers, Erica was to load sleepers for the expanding railway network back home.
When Erica berthed, an Aussie naval officer boarded. “The ship must be painted battleship grey,” he ordered the master, and, as Mallory wrote, “So the task of obliterating our fancy camouflage was carried out.”
The master was called up for war service in the Australian navy, prompting the promotion of the remaining deck officers and, to make up the numbers, a long-retired gent joined as third mate.
On completion of loading, Erica began her long and harrowing nineknot passage to Durban.
Fortunately, in those early stages of the war, Donitz’s U-boats had not reached the Indian Ocean, and the old steamer arrived in Durban untroubled.
Mallory joined the South African Navy during the war and, later, having commanded naval hydrographic survey ships, he was promoted to Captain and became the naval hydrographer.
It was more than merely a job – Mallory was keenly interested in wave patterns and became the first professor of oceanography at UCT.
He was intrigued by the well-documented incidents of serious wave damage to ships off the east coast, including the unexplained loss of the Blue Anchor liner Waratah in 1909, and wave damage to several other vessels, including Edinburgh Castle in 1964.
He focused on the causes of such damage and, apart from examining available records from damaged ships, he requested the masters of Ellerman&Bucknall ships to monitor conditions while steaming close to the 100-fathom line between Durban and East London.
SAS Protea and the UCT survey vessel Thomas B Davie also monitored conditions.
By collating information from these and other vessels, Mallory concluded that abnormal waves were experienced when certain phenomena occurred simultaneously along the coast: a depression was moving from the west; a south-westerly gale was blowing, causing large swells where it blew over the contrary-flowing Agulhas Current, and the current was flowing abnormally quickly.
These conditions sometimes generated a wave of around 18 metres, preceded by an abnormally long trough, moving at about 30 knots.
A ship in its path would dig into the wall of water that then would break over the vessel’s foredeck, often causing serious damage.
Although modern satellites help to identify conditions conducive to the formation of abnormal waves, the initial research was done by Captain Mallory who died in 1993, and whose name these rogue waves now carry.