"The steel used to build the Titanic was not as 'impact-resistant' as modern steel, according to Dr. H.P. Leighly, a professor emeritus of metallurgical engineering."
Dr Leighly studied about 200 pounds of steel recovered from the Titanic wreck. The steel showed a high concentration of sulphur, oxygen and phosphorous, which together also makes for a more brittle steel. Correspondingly, the concentration of manganese, a factor of ductility, was low in this steel.The steel's lack of ductility (pliability) and tendency to crack in very cold water as seen in the case of the Titanic. In contrast the Agulhas current is relatively warm (+/- 22 degrees centigrade) in winter, but surrounding seas are considerably colder in July, sometimes as low as 10 degrees centigrade (similar to North Atlantic in winter).
Over and above the poor quality of the hull steel, investigations revealed that the rivets themselves, cast from wrought iron, had three times the concentration of slag particles (dendrites of iron oxide) as would be considered acceptable. So in effect one would get de-cohesion between the iron and the slag particles, compromising the strength of the rivets. It is quite possible that similar rivets were used in the construction of the Waratah. So, we have a steamship constructed with a double hull, but using steel and rivets with an inherent tendency to crack or snap, rather than 'bend'.
Ships are subjected to a number of forces on the ocean, such as:
As a ship moves through the water (whether it be rough or smooth), the hull plates are subjected to fluctuations in water pressure, causing what is known as and 'in-out' movement of the plates. The steel described above would make these plates vulnerable to fatigue fractures, which may not initially be visible to the naked eye.
As a ship pitches and rams oncoming swells in heavy seas, pounding stresses occur. These stresses are particularly significant in 'light' vessels such as the Waratah.
Again the brittle steel hull plates and rivets would be vulnerable to this type of force.
Hogging & sagging :
Hogging occurs when a vessel is unevenly loaded with weight concentrated on either end. The converse of this is sagging when the cargo is concentrated on the centre of the vessel. Both place undue stress forces on already brittle steel. It was imperative that the officers in charge supervised loading and discharging of vessels to ensure that the cargo was evenly distributed. In addition to this, they needed to be alert when negotiating crests or troughs where the wavelength was equal to the length of the ship, thus causing hogging or sagging.
These are very important stresses in the context of the Waratah. This occurs when the hull of the vessel is 'twisted' due to the effects of an oblique sea or unequal distribution of transverse cargo weight. If carcasses had shifted in cargo hold 1, combining with water accumulation on one side, leading to unequal transverse weight distribution, these torsion stresses could have caused brittle hull plates to crack, water tight partitions to buckle and allow leaks through cracks.
Racking stresses occur when a ship's hull is distorted transversely due to the effect of rolling. According to witnesses, the Waratah rolled excessively.
Dry docking stress :
This is the stress that occurs when a vessel takes up bottom blocks in the drydock.
Rolling and pitching:
These forces acting together produce upwards and downwards acceleration forces, the values of which increase with the distance from the rolling and pitching.
We have transcript testimony that the Waratah ran aground for six hours off Kangaroo Island, Australia, in December 1908, witnessed by a cook by the name of Trott and a steward, Shore. This was not confirmed in the log, but does seem like a rather extraordinary flight of fancy (if false witness accounts) on the parts of both Trott AND Shore. Again it seems unlikely to me that they would allege something on a scale such as this, without some basis of truth. Subsequent to this incident shifting of the superstructure was also noted by one sailor who claimed he could put his hand between deck planks and a bolt which fell from the upper decks, hitting the baker on his head in the bakery below.
After her maiden voyage, the Waratah was dry docked and checked, before leaving on her second voyage. This would have subjected her hull to the dry docking stresses mentioned above and also hairline cracks and weakened steel rivets and plates may not have been noticed or attended to at this stage.
The Waratah had a double hull and water tight compartments, similar to the Titanic, creating a false sense of security. It is conceivable that the Waratah had latent defects in her hull before she departed from Durban Port on 26 July, 1909. These defects may have manifested due to the following factors:
- brittle nature of the steel and rivets;
- running aground off Kangaroo Island damage to hull;
- taking the ground at the wharf, Port Adelaide;
- heat damage from ongoing smouldering coal fires;
- the dry docking forces after her maiden voyage;
- her tendency to roll and pitch excessively ---> acceleration forces, particularly noticed by S. P. Lamont on the Clan Macintyre
- the torsion forces exerted by the rough oblique (changing) Wild Coast seas and shift of cargo leading to the uneven distribution of weight.
- as well as the pounding, racking, panting, hogging and sagging stresses listed above.
This may all have been too much for the new liner. As a result of these continuous racking, torsion and pounding stresses from the rough seas and approaching storm, the Waratah probably developed cracks in her hull plates, in areas where the brittle steel and rivets were weakened. Some partitions probably buckled between water tight compartments. Water would have started to enter these vulnerable sections at an increasing rate, which in time would overwhelm the bilge pumps, and the capabilities of the crew.
As in the case of the Titanic, rivets may have snapped, creating the zipper-type effect where a seam of rivets snap successively between hull plates, opening up a 'gash' in a force driven 'domino effect'. If this were to have happened, there is no question in my mind that the Waratah would have gone down very quickly indeed.
I believe that Captain Ilbery was aware of the extent of the problem and realised that he had to get his steamship safely back to Durban, before her buoyancy card was played out. Listing badly and vulnerable to swells broaching her hatches, in sight of the SS Harlow and Cape Hermes shore, the flagship for the Blue Anchor Line, Waratah, buried her bow into the oncoming swell for the last time at about 8 pm 27 July, 1909, and in all probability lies in just 37 m of water
|Waratah is launched. From cradle to grave by the following year.|