The Second Explosion

Did exploding munitions sink Lusitania?  If not, what caused her to sink so quickly, especially if she was almost as big as Titanic? No one knows for sure, as Lusitania is resting with her torpedo wound against the sea floor.  Theories of what caused the Lusitania to sink are many, and the debate on which theory is most likely continues to be debated. Here are possible explosion theories in alphabetical order:

• Aluminum powder explosion, advanced by Patrick O’Sullivan.  A torpedo hitting the magazine could have kicked the stored aluminum powder into the air. As the powder settled, it would have reached explosive concentrations, triggering the second explosion.  None of the baggage handlers who were above the magazine survived the sinking.  Furthermore, the washing up of furs along the Irish coast indicate that the cargo hold was indeed breached during the sinking. The likelihood of this theory depends on where the torpedo hit. As the wreck lies on its side, we cannot know for sure if the torpedo hit the magazine, or slightly aft in the coal bunker under the bridge, as proposed by Ballard’s 1995 expedition. From parts of the starboard bow that Ballard was able to see, there did not seem to be explosion damage from at least the forward end of the magazine. The editor thinks that the idea that aluminum powder in 1915 would not be refined enough to reach explosive concentrations is moot, as no matter uneven the quality of the powder may have been, once kicked into the air, the heavier particles would have settled first, leaving the finer particles in the air that could have reached explosive concentrations.

• Ammunition.  The declared ammunition on the cargo manifest would have been insufficient to cause a fatal explosion, but if the shrapnel shells were indeed filled with gunpowder and live (as confirmed by The Royal Artillery Regiment’s Historical Trust), then an explosion is possible.  Again, none of the baggage handlers who were above the magazine survived the sinking, and the cargo hold was breached. Like the aluminum powder theory, the likelihood of this theory depends on if the torpedo did hit as far forward as the magazine, or further aft. As lifeboat 5 had been knocked overboard by a descending column of water, it is clear that the torpedo had it forward of this area, as Lusitania would have sailed forward as the blast column descended. Dr. Bullen, Maritime Curator at the Imperial War Museum, believes that even having the torpedo impact near the cargo hold instead of in it may have been enough to trigger a sympathetic explosion. Eyewitness accounts state that the officers on the bridge had been enveloped in a steam cloud at the time of the explosion, probably coming through breached vents surrounding the first funnel. Survivor Elizabeth Duckworth, standing on the forecastle deck at the time, recalled cinders and debris raining down on her. The editor has not come across any account specifically mentioning the explosion cloud coming out of the cargo hatch, although it is likely that the force of the explosion would have found the least resistance through the opening caused by the torpedo impact. A blast directed outwards would have triggered the water column witnessed by those on board.

• Boiler explosion.  The fact that all functioning boiler rooms had survivors indicate that this is unlikely to be the source of the second explosion.  Furthermore, the expulsion of Inspector Pierpoint, Margaret Gwyer, and Harold Taylor from funnel #2 late in the sinking suggests that several minutes, not seconds, elapsed between the torpedo impact and any boiler explosions.

• Coal dust explosion, advanced by Dr. Robert Ballard, discoverer of the Titanic wreck.  A torpedo hitting under the bridge, as described by witnesses, would have hit the forward coal bunker and not the magazine forward of it.  The torpedo could have kicked the coal dust into the air, and much like the aluminum powder theory, would have reached explosive concentrations as it settled, triggering the second explosion.  Against this theory is the supposition that coal dust in the bunkers would be damp with condensation, as the steel hull was in constant contact with the cold sea water.  Thus coal not already used up would not be easily kicked up into dust by the detonation of the torpedo. Ballard’s investigation of the wreck noted that what was visible of the starboard bow did not seem to be damaged by an internal explosion. This indicates that the point of torpedo impact was somewhere forward of the first boiler room and aft end of the cargo hold, where the forward coal bunker was located.

• Pipe bomb, advanced by Max Allan Collins.  Germany had been developing pipe bombs for destroying Allied munitions supplies during World War I, the most famous case of German sabotage being the Black Tom explosion of 30 July 1916 in Jersey City, New Jersey, United States.  This explosion destroyed the major munitions depot of the northeastern United States. Inspector Pierpoint had arrested three German spies on board Lusitania just after the liner’s last departure from New York.  The men were supposedly found with a camera, but the mission of the men remains unknown.  In light of known actions of German agents abroad, it is possible that German agents planted a pipe bomb in the cargo hold to destroy contraband going to the British, and that the bomb was detonated by the torpedo impact.

• Steam line rupture.  This theory states that one torpedo was sufficient to sink the ship, having targeted a weak spot in the ship’s design, and that the second explosion (the steam rupture) was not fatal to Lusitania.  The torpedo would have had to either coincidentally hit the spot on Lusitania that would trigger the catastrophic structural failure, or unforeseen design flaws would have made any part of the ship vulnerable.  The longitudinal bulkheads, designed to limit flooding, concentrated the weight of water on one side of the ship and endangered Lusitania‘s stability, causing her sinking.  The weight of coal and cargo being shifted to the starboard side of the list may not have helped matters. Against this theory is that the much smaller Candidate and Centurion took much longer to sink despite also being torpedoed once by the same submarine.

• Second torpedo, the favorite theory of the Mersey and Mayer inquests.  Some witnesses such as William Adams claimed to have seen two torpedoes strike Lusitania, and Joseph Casey even claimed to have seen a third torpedo head toward Lusitania.  This theory is contradicted by Schwieger’s war diary and the testimony of everyone in U-20. If another torpedo had been fired, it would have been from another submarine in the area and not the U-20.  No other submarine has claimed credit for also sinking Lusitania, but if the theory is right, then perhaps the sinking’s international backlash against Germany would have kept any other submarine crews quiet.

• The torpedo itself, advanced by historian Jim Kalafus. Lusitania was not the only 4-stacker torpedoed during World War I. The American USS Mount Vernon, formerly the German Kronprinzessin Cecilie, had also been torpedoed but survived. Accounts from the Mount Vernon did not describe the torpedoing as a “bump” or sounding like the “breaking of glass” as accounts from the Lusitania do, but rather as a massive explosion. The torpedo damage to the Mount Vernon would have sank the ship if not for the well-trained crew aboard the ship. Therefore, it would have been possible that the “bump” was just the torpedo hitting the ship, with the detonation coming after. However, torpedoes from the time period had contact detonators and did not have delays built into the ignition train. A World War I-era torpedo hitting Lusitania should have detonated on impact and not had the seconds between impact and detonation that survivors recall. But, if this theory is correct, then the Lusitania‘s loss is even more tragic and senseless, as that means that the ship and all those on board could have been saved even after the torpedoing.

Unless there is some way to find the torpedo wounds in Lusitania when she is lying on her impacted side, we may never know for sure the cause of her sinking.

Contributors:
Jim Kalafus, USA
Mitch Peeke, UK
Eric Sauder, USA

References:
Ballard, Dr. Robert D. and Spencer Dunmore.  Exploring the Lusitania.  Warner Books, 1995.

Beesly, Patrick.  Room 40.  Harcourt Brace Jovanovich, 1982.

O’Sullivan, Patrick.  The Lusitania:  Unravelling the Mysteries.  Collins Press, 1998.

Peeke, Mitch, Kevin Walsh-Johnson, and Steve Jones. The Lusitania Story.  US Naval Institute Press, 2003.

Simpson, Colin.  The Lusitania.  Little, Brown, and Company, 1972.