Tuesday, 26 April 2016

PERMANENT COAL AND WATER BALLAST CONUNDRUM.

Clause 5 .... "and to be designed, if possible, to go to sea with permanent coal and water ballast only."

COAL - 


Permanent:

hold cross bunker                            382 tons
lower deck (port and starboard)      137.5 tons x 2 = 275 tons
main deck (below spar)                   583 tons
coal trunk                                         81 tons
coal chute                                         59 tons
spar deck                                          614 tons
pocket bunker                                   10 tons
pocket bunker                                    6 tons

total                                                    2010 tons

Reserve:

No 3 hold                                           859 tons
lower 'tween decks                            491 tons
upper 'tween decks                            382 tons

total                                                     1819 tons

grand total                                           3829 tons


BALLAST TANKS -

number 1                                             129 tons
number 2                                             219 tons
number 3                                             168 tons           divided into 2
number 4                                             118 tons           divided into 4        fresh water*
number 5                                             179 tons
number 6                                             78 tons                                           fresh water*    * 279 tons
number 7                                             83 tons             divided into 2        fresh water*
number 8                                             222 tons           (builders advised filling this tank)
number 9                                             42 tons
forepeak                                              53 tons
afterpeak                                             47 tons

total                                                     1338 tons

Numbers 1; 2; 5; 6; 8; 9; forepeak and afterpeak tanks were pierced with holes.

If Waratah held permanent coal and ballast tanks were full = 3348 tons.

There would have been problems relating to coal distributed as follows at 42 cubic feet to the ton:

- spar deck                                            614 tons                  (coal trunk / coal chute / pocket bunkers
- main deck                                           583 tons                                       156 tons. - 7.7%)

total                                                       1197 tons.             



According to the design plans of Waratah, bearing in mind the third deck, it is astounding that the majority (60%) of permanent coal stowage was intended for higher up in the vessel. Clearly stowing coal in this fashion would significantly raise the centre of gravity and reduce GM and the builders had not taken heed of the owners' request.

But we know from various reports that coal and cargo were stowed interchangeably in either holds or bunkers. With this flexibility, the distribution of weight and all important centre of gravity, could be manipulated and in so doing the Waratah would have been able to go to sea safely with permanent coal supply and ballast tanks full, preferably with the coal stowed on the lower deck.

It could be done, but not by following the builders' bunker layout. The builders, naturally, had to design the ship with the priority given to cargo stowage, not coal, and I doubt whether in practice there was much planned need for Waratah to go to see with just ballast water and permanent coal. I suspect the owners were playing with this conundrum at the Inquiry to show the builders up in a poor light.

Manipulation upon manipulation.




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