Wednesday, 16 October 2013

PROFESSOR BRAGG; SEDGWICK; TWEEDIE; BURRIN.

William H. Bragg. Passenger and Fellow of Royal Society and Cavendish Professor of physics at the University of Leeds (fourth voyage) -

"I was very alarmed"

Oh, dear, here we go...

"Thought she was unstable for small displacements, but stable for larger ones."

This statement makes complete sense. Waratah was inherently tender and required significant dead weight displacement to correct and improve the GM.

"My impression was that metacentre was just slightly below centre of gravity when she was upright, and then as she heeled over on either side she came to a position of equilibrium."

This referred to the maiden voyage when the Waratah's GM was low, if not slightly negative. This state of affairs was directly related to Waratah's dead weight displacement (relatively low) and stowage plan which needed corrections.

"Judging by the camber the list was four or five degrees"

Perhaps Sawyer was misquoted and instead of 45 degrees he was referring to 4 or 5 degrees.  He was after all an engineer and the image in a previous post of a vessel listing at 45 degrees is clearly not a seaworthy option.

"The list would last for several days in one direction"

Thus confirming equilibrium in that position.

"One morning she came upright, then went over, and stopped down on the other side."

"The vessel got more upright getting towards Durban. After leaving Cape Town the list developed again."

"I was surprised to find how little she rolled, but that fitted in with her being in neutral equilibrium."

"Thought she was a remarkably steady and comfortable boat"

Well, that's a relief.  Back to stability and comfort, which negate the listing peculiarities, and more importantly use of the word 'steady' which does not imply dangerous.

"Often talked to the captain about the stability of ships, but never put a direct question about this ship and asked for stability curves, but was told they were not on board."

Stability curves should have been on board for the maiden voyage.

"Spoke to the chief engineer who said she was safe as a church, that if necessary the tanks would be filled, and she would then be as stiff as a board."

Again this refers back to the logical displacement argument. With ballast tanks filled Waratah would have had the all-important increase in dead weight lowest down, significantly improving GM, but at the expense of the buoyancy factor?

Alfred Montague Sedgwick.  Passenger (30 voyages) -

"Appeared to be top heavy and cumbersome, heavy above water"

"Rolled a good deal, but no jerk. Seemed to go right over as far as the roll would carry her, then seemed to be dead and did not come back."

There would not have been a 'jerk' at this stage with a low GM and reduced righting force. The 'jerk' was a manifestation of a vastly improved GM, final voyage.

"Seemed to hesitate a second or two before she came back in a sort of dead still"

A good number of witnesses to date have given the same story that she held in a list before returning to an upright position. Some expressed opinions that this was peculiar and 'unstable' while others simply found it amusing, the Waratah comfortable, and no reflection on her stability and safety. Let's not forget safe Naval vessels displayed a similar pattern. 

David Tweedie. Passenger (about 16 voyages and personal friend of the Messrs. Lund) -

"Never in a better ship and never had a better voyage"

Oh dear, the friendship bias creeping in?

"Less rolling than I have seen in other ships"

"No jerk or hang in the roll"

"The chief engineer was very pleased with her, and likewise the captain"

"She seemed to go through the water like a duck"

At least not a sitting duck...

"Never pitched heavily at any time"

"Quite incorrect to say she had a permanent list to one side or the other, or that she had a heavy list for some days."

No, I think his loyalty to the Lunds may have clouded his statement.  Nice, and in favour of the Waratah's stability, but to be taken with a pinch of the proverbial.

Thomas John Burrin. Pantryman on the Waratah (11 years at sea) -

"Rolled in the same way as any other vessel would roll in a high sea; nothing unusual about her behaviour; carried herself well in the sea. Did not dive. At times listed, but would right herself and be on an even keel for a week or so"

'Did not dive' was an important observation on the maiden voyage - tender but significant buoyancy - compared with the final voyage when Waratah had a tendency to put her nose into oncoming swells = improved GM at the expense of buoyancy.





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