She was to be built to Lloyd's Rules (1907-1908) for the 100 A1 spar-deck class with freeboard. The minimum freeboard when fully loaded to 30 feet 4 1/2 inches mean draught was 8 feet 1 inch. She was a larger ship than was contemplated by those rules, and her scantlings were practically the same as those for the three-deck class.
It is interesting to note that only one mean maximum draught figure was quoted at the Inquiry, implying that Waratah was not issued with a North-Atlantic winter loadline, a 2% reduction on the summer loadline (one may assume that the 30 ft. 4 1/2 in. applied to summer).
The argument put forward in the report is that winter conditions in the southern hemisphere did not approximate that experienced in the northern hemisphere. This cannot be said for, nor applied to, the Wild Coast, South Africa, midwinter. In fact, it is along this very coast that notorious rogue waves occur, dwarfing anything the worst of storms the mid-Atlantic can produce.
Of course, as calculated in the report, a varying loadline would have had a direct impact on cargo-carriage and profits. Given that 30 ft. 4 1/2 in. was Waratah's maximum draught in summer conditions, her draught in winter conditions should have been reduced to a mean of around 29.7 ft., which was only 3.6 inches short of the aft draught of 29.4 ft. rather than the assumed 11.7 inches, when Waratah departed Adelaide for the last time.
Furthermore, according to the wording of the Inquiry extract above, Waratah was larger than applied to 'those rules', including freeboard of 8 ft. 1 in.. A larger vessel would require a larger freeboard factor. A rough calculation would have LBP (465 ft.) / a factor of 40, which gives a rough freeboard of 11.6 ft. for a vessel the size of Waratah. Obviously there are other subtle factors taken into account which would not alter this figure significantly. A freeboard of 11.6 ft. would give a maximum summer draught of 26.85 ft.. i.e. 26 ft. 10.2 in..
Let's return for a moment to the SS Vestris, which was registered for a summer draught of 26 ft. 9.25 in.. Is it not strange or merely coincidental that the similarly, if somewhat larger, Vestris had a summer draught, a meager 0.75 in., less than my estimation for Waratah??
Taking this exercise further, one can extrapolate a winter draught figure for Waratah - 26.3 ft., which is 2.7 ft. less than the mean 29 ft. draught when Waratah departed both Adelaide and Durban for the last time. Waratah was functionally overloaded to the tune of 2.7 ft.!! Her registered maximum draught was a joke and NEVER explored by the Court of Inquiry. Naturally Waratah was exceedingly tender with a mean draught of 26.3 ft., which could never work in practice, forcing 'overloading' and heavy ballasting to improve GM.
Some consider this 'bleating', I consider this convincing!!