Well...In the fall of 2003, a group of divers explored and researched the liner, inside and out, and also ran sonar paths in the vincinity. Simon Mill's, Britannic's owner, accompanied them. The reason britannic sank so fast was greatly due to the fact that her watertight doors had been left open. The massive damage to Britannic does indeed suggest and internal explosion, possibly caused by a torpedo, however, there WAS a U-boat operating in that area just the day or so before and was not a conventional U-boat, it was a mine layer. The U-boat's skipper even admitted he managed to drop 17 or so mines before heading out of the Mediteranean. The sonar scans revealed strong evidence of these mines, finding remnants of unexploded and expldoed mine shells. However, for any kind of information on this great liner, i always refer to my good buddy from TT, Mark Chirnside. Mark is a great authority on Britannic and Olympic, and fairly easy to debate with.