Tuesday, 11 July 2017

OVERVIEW OF WARATAH'S STABILITY, FINAL VOYAGE.

Inquiry:


To enable a critical examination to be undertaken of the evidence as to the ship's behaviour on her second homeward voyage, her approximate metacentric height when leaving each of the Australian ports has been calculated. It is as follows:



leaving Sydney               about foot



leaving Melbourne           about 1.5 feet



leaving Adelaide             about 1.9 feet




The above GM figures refer to the final voyage, when Captain Ilbery was able to deal with the issue of coal in 'tween decks, and apply the principals of significant dead weight, lowest down. Not one of the figures correlates with a top heavy or tender steamer. The progression of the figures to a maximum of 1.9 ft. illustrates the cumulative dead weight cargo loaded from port to port, resulting in a very stable (GM) vessel. 

Mr McDiarmid, pilot, Port Adelaide:

 I was pilot to the "Waratah" inwards and outwards on her last voyage. Inwards. took charge of her 2 miles to the southward of the Port Adelaide Lighthouse and berthed her at the Ocean Steamers Wharf, Port Adelaide. She had the assistance of a tug which was placed right ahead all the way to assist at the bends in the river. Her draught, as recorded by me after berthing, was 25 feet 8 inches forward and 26 feet 4 inches aft. Pilotage is paid for on tonnage and not on draught. We steamed in slowly. Had no difficulty in steering the ship or otherwise.

It is interesting to note that despite an average draught of 26 ft. while being brought into Port Adelaide, Waratah's GM was alleged to be 1.5 ft.. This draught was AFTER ballast tanks had been pumped out, not reflecting the full GM of 1.5 ft. at sea. Despite a draught of 26 ft. Waratah was easy to 'steer', relating back to the essential, 1000 tons of lead concentrates midships, hold 3, at 10 - 11 cubic feet to the ton, 8 ft. high - a significantly stabilising factor - and with a further 300 - 500 tons to be added at Adelaide!



The heaviest cargo, lowest down, was loaded at Adelaide, ultimately achieving the GM figure of 1.9 ftBut how was it possible that by discharging a paltry 250 tons of cargo at Durban the GM could have fallen so significantly from 1.9 ft. to 1.5 ft. ? I shall return to this important point. 



The Court has no evidence as to the amount of water ballast in the tanks leaving Melbourne and Adelaide, and has been compelled to assume it from the draught. There is evidence that on leaving Sydney she had 651 tons of water ballast in the double bottom. This tallies with the draught given in the log. On leaving Melbourne and Adelaide 360 tons of water ballast are assumed for the reason given above. 



Waratah did operate on her final voyage with a small component (27% of 1338 tons) of ballast water, contributing to GM stability. The Waratah needed 651 tons of water ballast leaving Sydney, but only 360 tons, leaving Melbourne and Adelaide. Cumulative loading of cargo reduced the need for more than 360 tons of ballast water. Proportionately the largest portion of heavy cargo was loaded at Adelaide, raising the GM to 1.9 ft. It is interesting to note that ballast tank 1 did contain 129 tons of water. If one adds ballast tank 8 (222 tons), we get a figure of 351 tons (almost 360 tons), and if you recall, the builders advised the filling of ballast tank 8 to assist with GM stability.



In connection with the stability of the ship on this voyage, Mr. Wade's evidence may be mentioned to the effect that the captain told him that he (the captain) had learned the peculiarities of the ship, and now knew how to stow her. 



He sure did. 



It is not easy to reconcile metacentric heights such as those set out above with the positive testimony of some of the witnesses, as for example the tenderness on entering Adelaide spoken to by the witness McDiarmid. His deposition shows signs of careful observation. In the matter of the draught, for instance, his evidence is in accord with the log book, whereas the witness Johnson, whose evidence would otherwise discount McDiarmid's, is largely in error on this point. McDiarmid, however, adds that she showed no signs of tenderness when leaving Adelaide



There is a fair amount of evidence to show that the ship was upright when leaving each of the Australian ports. 

Waratah, departing Australian waters, was upright and not tender.

What about coal on the spar deck and stability?


Letters addressed by the owners to the builders after the maiden voyage showed that representations had been made to the owners by Captain Ilbery, and it was noted on the homeward voyage that he did not use the spar deck for coal.
We know that about 250 - 300 tons of coal was loaded on Waratah's spar deck at Durban. Captain Ilbery was well aware of the GM reducing factor caused by spar deck coal and 'it was noted that he did not use the spar deck for coal' on the homeward voyage. 
How can these statements correlate, and be true ??
We know that the Waratah had a GM of 1.9 ft. between Adelaide and Durban. Witnesses gave detailed accounts at the Inquiry of passengers being thrown off balance on deck due to the 'jerky recovery' which, in effect, was due to a vastly improved righting force (GM 1.9 ft.). A similar scenario was observed in the case of the inherently tender Yongala. Stabilising pig iron, rather than lead concentrates, was added as ballast resulting in a jerky recovery. 
This was a serious matter in terms of passenger safety and comfort. Captain Ilbery, master of the Waratah, was obliged to do something to improve the situation and, in my opinion, came up with an ingenious solution to the problem. He had manipulated loading and ballasting of the Waratah rather too well, creating the GM of 1.9 ft. which in essence was the problem. Ironically, when all is said and done about the Waratah being tender, she lashed back by creating a new set of problems for passengers in her revitalized highly stiff form. By loading 250 - 300 tons of coal on the spar deck, it reduced the GM to 1.5 ft. which was a cure for the 'jerky recovery'. No more injuries and more importantly a very satisfactory and stable GM of 1.5 ft..
In fact coal was left in the main chute (chutes could hold 130 tons) to within 2 ft. of the opening in front of the funnel on the boat deck. This further significant quantity of coal contributed to reducing GM to a more palatable level.
It was necessary to stow 250 - 300 tons of coal on the spar deck and it was done intentionally  !!!!!!



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