"On a draught of 19 ft. she
can carry 4000 tons of cargo."
This figure of 4000 tons was widely quoted in newspapers. But it is incorrect. Koombana's realistic cargo carrying capacity was in the region of 1800 tons - 1000 tons general cargo and 800 tons refrigerated cargo, stowed 100 cubic feet to the ton. With ballast tanks accounting for 900 tons of her overall volume 4000 tons was a stretch of someone's imagination. What is interesting, however, is the draught of 19 ft., which is the figure (aft) the Inquiry thought they could get away with for Koombana departing Port Hedland with a paltry 260 tons of cargo and empty ballast tanks!
To confirm the correction we must return to a comparison with the SS Yongala:
Koombana (1908) Yongala (1903)
gross tons 3668 3664
net tons 2182 1825
length 340 ft. 350 ft.
beam 48 ft. 2 in. 45.2 ft.
depth (of hold) 25 ft. 8 in. 27.2 ft.
hull depth 29.5 ft. 30.5 ft.
draught 20 ft. 8 in. 24 ft.
cargo 1800 tons 1800 tons
What becomes apparent are the marked similarities between the two steamers, particularly with regard to specifications and prominent top hampers. However, Yongala's narrower beam would likely have improved stability marginally compared with Koombana's slightly broader beam and flat bottom. It is patently clear that Koombana operated with a significantly reduced draught (related to Northwest coastal ports access); a differential of 3.25 ft.. This would have had a significantly negative impact on GM stability and although both steamers were visually top heavy, Koombana took the prize.
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| SS Koombana (courtesy wikipedia) |
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| SS Yongala (courtesy Michael McFadyen's scuba diving website) |
courtesy Trove.
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