One of the most unusual events of WW1 was the sinking of U28, apparently by a flying lorry;
"U-28 scored a torpedo hit, and closed in to finish the steamer with gunfire. The shells detonated the Olive Branch's cargo of munitions, which it had been carrying from England to Arkhangelsk, Russia, and the subsequent explosion so badly damaged the U-boat that it sank along with the steamer. All 39 of its crew were lost; some were seen swimming, but were not picked up by the Olive Branch's lifeboats.[4]
An alternative description of the event states that when the ammunition detonated, a truck carried as deck cargo was blown into the air and fell from a great height on the U-boat, sinking it.[5]"
From http://en.wikipedia.org/wiki/SM_U-28_%28Germany%29
I don't suppose it would be possible to trace which type of lorries the SS Olive Branch was carrying, and determine what type of lorry was likely to have sunk the U28?