We know that the Waratah was significantly overloaded, placing undue stress forces on her hull. Could she have experienced a similar fate off the Wild Coast?
|[hide]Conditions Necessary for a Fully Developed Sea at Given Wind Speeds, and the Parameters of the Resulting Waves|
|Wind Conditions||Wave Size|
|Wind Speed in One Direction||Fetch||Wind Duration||Average Height||Average Wavelength||Average Period and Speed|
|19 km/h (12 mph)||19 km (12 mi)||2 hr||0.27 m (0.9 ft)||8.5 m (28 ft)||3.0 sec 9.3 ft/sec|
|37 km/h (23 mph)||139 km (86 mi)||10 hr||1.5 m (4.9 ft)||33.8 m (111 ft)||5.7 sec 19.5 ft/sec|
|56 km/h (35 mph)||518 km (322 mi)||23 hr||4.1 m (13.6 ft)||76.5 m (251 ft)||8.6 sec 29.2 ft/sec|
|74 km/h (46 mph)||1,313 km (816 mi)||42 hr||8.5 m (27.9 ft)||136 m (446 ft)||11.4 sec 39.1 ft/sec|
|92 km/h (58 mph)||2,627 km (1,633 mi)||69 hr||14.8 m (48.7 ft)||212.2 m (696 ft)||14.3 sec 48.7 ft/sec|
The above chart gives a better understanding of the factors contributing to wave length. According to the data, a gale would have to be blowing at roughly 75 km/hr (47 mph) over a sustained period of at least 42 hours in order to create a wave length approximating the length of the Waratah - 465 ft. (141.7 m). Could this have been possible off Cape Hermes late 27 July, 1909. The simple answer is 'no'. The Captain of the Harlow clearly stated in his account that the storm approaching from the southwest had not materialized off Cape Hermes by that time.
If, for arguments' sake, the Waratah had continued on course for Cape Town and run into the 'storm of exceptional violence'. Within the first 24 hours of the storm, it is not possible, given the data above, that the wave length could have achieved 141.7 m.
However, shorter wavelengths, in a turbulent, stormy sea create significant forces against an already strained hull. The excessive rolling and pitching forces could theoretically cause failure of a compromised hull. It stands to reason Captain Ilbery, under the circumstances, made a decision to turn back for Durban. One thing is clear, whatever presented the final straw for the Waratah's hull integrity, could not have been in the form of a 'back-breaking' wave length.