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Friday, June 14, 2013

German G7e Torpedo Warhead and Its Ghostly Image

Shown here is a torpedo warhead recovered from the German submarine U-352 by U.S. Navy explosive ordnance disposal divers in the 1980s.  It is currently on display in the museum's World War II gallery.  The warhead comes from a G7e electric torpedo, one of twelve carried by the submarine. The warhead would have carried about 618 pounds (280 kilograms) of an explosive mixture known as Schießwolle 36 or Guncotton 36 (having been invented in 1936).  It contained a mixture of 67 percent  TNT, 25 percent aluminum powder, and 8 percent HND (a highly toxic explosive booster). 

A type VIIc U-boat, U-352 patrolled the American coast line in the Spring of 1942.  She did not have any success before being discovered by the Coast Guard ship USCG Icarus (WPC-110) southeast of Cape Hatteras.  352 actually got off the first shot, but the torpedo went wide and exploded prematurely.  Icarus closed the distance and fired off five depth charges in a diamond pattern.  The resulting explosions critically damaged 352 and forced her to the surface.  Icarus immediately opened up on the submarine with her 3-inch gun and machine-guns.  Already taking on water, the  submarine went down for the final time. Before the boat went down, thirty-three of her crew jumped into the water.  Icarus rescued and captured them all.

A close up of the pareidolia inside the
 museum's German torpedo warhead.
In the 1980s, the West German government requested that the United States remove all remaining human remains from the boat after receiving reports of looting.  It was during this recovery operation that the museum received the warhead.  Today, the National Oceanographic and Atmospheric Administration's Marine Sanctuary office oversees the site and educates divers about the nature of the wreck.

This artifact is a favorite among HRNM docents because what can been see inside the warhead.  Years of oxidation and corrosion has created a white pattern of what looks like a face.  While this may be no more than a pareidolia, some think they are seeing a ghost.  Come see for yourself!

2 comments:

  1. The HND (hexanitrodiphenylamine)at 8% of total warhead explosive is not a booster. It is a desensitizer, rendering TNT insensitive enough that the charge will not be detonated by small arms or even by some autocannon explosive rounds.

    Germans used a kilo of pelletized picric acid as the booster in sea mines loaded with the same explosive as this torpedo (Schießwolle 36), I don't have any data on boosters for this torpedo warhead-

    See this reference for more on early formulations of insensitive military HE:
    https://www.google.com/url?sa=t&source=web&rct=j&url=http://onlinelibrary.wiley.com/doi/10.1002/prep.201680373/pdf&ved=2ahUKEwjHs-yf3tDfAhWIUt8KHSKnDsgQFjACegQICRAB&usg=AOvVaw3IkiVmM5ylGx23ynVz-wrw

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  2. The Pistol (ie detonating mechanism) for this type Ka or Kb warhead would be Pi1 or Pi2 (later renamed TZ2).
    They all used a boostercharge of 300g Pentrite set off by two or four standard detonator capsules, either by mecanical or electrical activation (some variants of the pistols used a combination; ie two mechanical and two electrical detonators).

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