Wednesday, 2 December 2015

WARATAH, GEELONG STABILITY COMPARISON.

The Stability of the Ship. 

It will be observed that from the inception of the design the question of stability had received continuous consideration. As embodied in the specification which formed part of the contract, the requirements as to stability were two in number, as previously mentioned. They were set out at the end of clause 5 of the specification as follows:

(1) "Vessel to be able to stand and shift without any ballast," and 

(2) "to be designed if possible to go to sea with permanent coal and water ballast only." 

There was evidence to show that condition (1) was actually fulfilled. 

The words "if possible" in (2) were introduced because the builders were of opinion that the requirement could not be carried out if the coal to be carried in the spar-deck bunker were intended to be included in the permanent coal." 

We have covered this in detail:

http://waratahrevisited.blogspot.co.za/2015/11/waratah-inquiry-continued-part-14.html

'If possible' was never to be under these conditions. 

The insertion of the words "if possible" rendered nugatory either this paragraph (2), or the requirement, which appears earlier in clause 5, that the ship should be capable of taking about 2,100 tons of coal in permanent bunkers. 

The Waratah was certainly capable of taking 2100 tons of coal in her permanent bunkers. Problems with GM arose when the 'tween deck reserve bunkers were loaded with coal, and in addition to this, the spar deck bunkers. 

It appears to the Court that only one of four people could be responsible for this clause in its first shape (i.e., without the words "if possible"). Mr. F. W. Lund, Mr. Shanks, and Mr. Bidwell, each stated that he was not the author of the clause. It therefore appears that it must have been Captain Ilbery's suggestion, and, if so, was presumably based upon his experience. It is reasonable to suppose he had found that a ship capable of fulfilling this condition would present no difficulty in loading during the varying seasons of the Australian trade. It seems unfortunate from the owners' point of view that a condition suggested by the wide experience of such a trusted adviser as Captain Ilbery should have been so lightly abandoned.

So much truth in this paragraph. Captain Ilbery clearly understood the nature of the Waratah 'beast'. 

see:

http://waratahrevisited.blogspot.com/2015/12/gm-finale-and-conclusion.html

Paragraph (2) was subsequently given up upon an understanding that the stability of the "Waratah" should be greater than that of the "Geelong." (See the correspondence of December, 1907, set out ante.) 

It may be that the owners attached no exact technical signification to the phrase "greater stability than the 'Geelong,'" but the only meaning which, in the Court's opinion, can be fairly deduced from the phrase when used in substitution for paragraph (2), is that the "Waratah" should be better able than the "Geelong" to proceed to sea in the light condition. A comparison of the stability of the two vessels in corresponding conditions is here set out. 

This reinvents nitpicking. For the purposes of the Inquiry, comparisons should now have been limited to only one condition; fully loaded and ballasted, as was the case when the Waratah departed Durban for the final time. However, be that as it may....

"Waratah." 

"Geelong." 

 in Feet. 

1. Metacentric height in extreme light condition (except that 300 tons of fresh water, stores, &c. are on board). 

+ .26  (Waratah)

+ .16  (Geelong)

2. Metacentric height with vessel in light condition (i.e., with water ballast and permanent coal). 

+ .69  (Waratah)                incorrect figure quoted  + .52 ft.

+ .07  (Geelong)

2a. Ditto., but without spar-deck coal in "Waratah." 

+ .52 (Waratah)                 incorrect figure quoted  + .83 ft.


3. Metacentric height with permanent coal on board (for "Waratah," including 614 tons on the spar-deck), no water ballast, homogeneous cargo in all cargo spaces of such density as to sink vessel to loadline. 

+ .48 (Waratah)                incorrect figure quoted + .375 ft.

+ .22 (Geelong)

From the foregoing it will be evident that, without the spar-deck coal, the "Waratah" was better able than the "Geelong" to go to sea light. This, however, leaves the "Waratah" with only about 1,400 tons of permanent coal, and if it be assumed that the 614 tons left out of the spar-deck bunker is stowed in one of the lower reserve bunkers, the "Waratah" compares still more favourably with the "Geelong."

Where does one start with such an outrageous section. In addition to incorrect figures quoted, corrected in blue, the Court saw fit to present the GM deteriorating  (+ .69 to + .52) after burning out the spar deck coal! They had lost the plot by this stage, made worse by the claim that only 1400 tons of permanent coal remained. But more damning and alarming than the incorrect figures and misleading overall information, are the outrageous figures attached to the Geelong! And I am the one labeled as dishing out incorrect figures to the general public! For every figure quoted re Geelong, there should at least be the numeral 1 before the decimal point! It all comes down to common sense and the information laid out in preceding posts. The Geelong was not naturally GM unstable (top heavy) compared with the Waratah, which was. The twin decks and general dimensions did not naturally create problems for the Geelong which would have required complex coal and cargo arrangements, and more importantly, functional overloading +/- the manipulation of ballast tank filling. There was one witness who compared the Geelong to the Waratah; Mrs. Hay, commented during Waratah's maiden voyage:


'The apparent top-heaviness of the Waratah appears tohave no effect on the easy passage of thesteamer through the water as it is counteracted by her breadth of beam (roughly the length of a bowling alley). Havingtravelled three times in the Geelong, onenaturally compares the two steamers, andthe conclusion arrived at is that the loftybuild of the Waratah does not cause any excess of motion, but that this is, if anything,less in her than the Geelong.


Mrs. Hay, commented on the 'apparent' top-heaviness of the Waratah. Sensibly she included the word 'apparent' because, as we know, top-heaviness / GM could be manipulated by weight low down in the hull. But for the maiden voyage there were undoubtedly issues relating to top-heaviness. It is also interesting to note that passengers such as Mrs. Hay were aware of the top heavy impressions. However, Mrs. Hay hazarded a vote of confidence relating to the Waratah's beam, which was 59.45 ft. compared with the Geelong's 54.5 ft. - hardly a vast difference (10%). But she made a vital comment; 'excess of motion, less in her than the Geelong'.  A tender, top heavy ship like the Waratah had longer, slower rolls, many times hanging in the list. The Geelong, on the other hand being more GM stable, would have had more frequent, sharper rolls relating to her healthier tendency to find the upright position. Indirectly, Mrs. Hay confirmed that the Geelong was more GM stable than the Waratah. Passenger steamers were designed to be relatively tender, enhancing passenger comfort, which Mrs. Hay alluded to in her revealing comment.

Although the Court has not found it possible to discover from Mr. Lund exactly what meaning he attached to the words "greater stability than the 'Geelong,'" it seems not unlikely that he intended a comparison between the two ships in similar conditions of lading. For this reason the third condition has been added to the above comparison of stability, and from this it will be seen that somewhat more care would be required in loading the "Waratah" than the "Geelong" to obtain equally satisfactory stability conditions. 

I suppose one could argue that this paragraph suggests that the figures quoted were erroneous, but not intentional. The Court did come to the conclusion (relief) that 'more care would be required in loading the Waratah than the Geelong.' Sense reestablished.








to be continued...

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