156 BUOYANCY AND STABILITY OF TROOP TRANSPORTS. 



and are in some ships provided with holes, which in case of bilging permit an equali- 

 zation of the water from one side to the other. Ordinarily, however, the water 

 must rise to a considerable height on one side before it begins to equalize, especially 

 where the bulkhead is fitted over a tunnel and the holes are at a high level. Often 

 the flow is very sluggish, because the openings are choked by coal. Thus shifting 

 bulkheads, temporarily at least, have the same effect as if they were watertight. 



A striking proof of the dangers of such quasi-longitudinal subdivision is fur- 

 nished by the loss of S. S. Empress of Ireland in May, 1914, as the result of a 

 collision with S. S. Storstad. The Empress of Ireland had two large boiler-rooms, 

 each with a cross bunker at either end connected by side bunkers. All the bunker 

 bulkheads were non-watertight. Water could flow freely from the side bunkers 

 into the adjacent cross bunkers, but at the center line in these latter were fitted longi- 

 tudinal passages and shifting bulkheads which, although provided with holes, greatly 

 retarded the equalization of water from one side to the other inside the bunkers (see 

 Plate 55). The ship was otherwise subdivided on the transverse system. At the 

 time of the collision the bunkers were practically full of coal. 



The Storstad struck the Empress of Ireland almost at right angles on the star- 

 board side in way of bulkhead No. 5, which separates the two boiler-rooms from 

 each other. A breach was produced in the side of the Empress of Ireland of an 

 area below the water-line, estimated to be not less than 350 square feet — about the 

 same size of hole as would be produced by the explosion of a torpedo. The imme- 

 diate effect of the damage was that the watertightness of bulkhead No. 5 was de- 

 stroyed and that both boiler-rooms were put in communication with the sea. Flood- 

 ing of these compartments involved a mean sinkage of practically 9 feet, which took 

 the main deck 4 feet below the water at the center line amidships. At the same time 

 the ship took a heavy list. 



Quoting from the Parliamentary Report, p. 17: — "There is no evidence that 

 the Storstad destroyed any portion of the bunker bulkheads, so that very shortly 

 after the impact a large quantity of water must have entered the bunkers on the 

 starboard side for the whole length of the boiler-rooms, which water was able to 

 escape only through bunker doors into the boiler-rooms and "relatively"* slowly also 

 across the middle-line partitions in coal bunkers to the port side of the vessel. 

 Under these circumstances the ship would at once commence to list to starboard 

 * * * making reasonable approximations, an inclination of some 15 to 20 de- 

 grees appears probable. * * * From such a list the vessel might have recovered 

 as the water got to the port side, if all port holes, and all watertight doors in bulk- 

 heads bounding the boiler compartments up to the upper deck, had been closed, but 

 with doors and side lights open to the extent known to have obtained after the col- 

 lision, water was free to enter other compartments, and the final capsizing and 

 foundering became inevitable." 



It is clear from this that it was owing to the presence of side bunkers and shift- 



*Quotation marks are by the author. 



