Really? I mean, the after section of the ship is utterly destroyed.....
The center section is not And most of the aft is present. Blast and tear damage is present there and we use that to ascertain the direction of the internal explosion. Refer to page 5 for rudder position and other details in the citation as to the wreck condition.
Also discussion here.
Some correction is to be made in here, as HMS Hood's wreckage shows clearly the ship was not broken in two, but in three major parts. A BBC Documentary once showed the wreckage and a computeranimated simulation, how this could have happened. (There also is a good piece of literature of: Mearns, D.: "Hood and Bismarck", ISBN-10: 0752220357, or ISBN-13: 978-0752220352.)
HMS Hood was hit in the main after magazine by a 15 inch shell of Bismarck, resulting in a direct detonation of all the powder of both 15 inch and 4 inch magazines, breaking of the sternsection, but secondarily resulted in a shockwave moving foreward, detonating the foreward main magazine as well. The large piece of wreckage flung into the air, observed by both Germans and British sailors was NOT a main gunturret, but the Armored Controll Tower, which is completely seperated of the main wreck, some hundreds of yards away from the actual wreck. Sinche the complete bow is missing too, it can only be the result of a foreward magazine explosion as the CT itself is not the lightest part of the ship, weiging several hundreds of tons at least. The force needed to seperate such a heavy part of the ship is enormeous, and only the explosive power of the main magazine (several dozens of tons of high explosives).
USS Arizona's magazine explosion was localized in her foreward magazine only, resulting in the ship slpitting in two parts, making this different from HMS Hood's catastrophic loss. More likely, USS Arizona's misshap was more simmilar to the one on the Russian Marat, after hits from Luftwaffe Stuka's. Also the magazine explosion on Bretagne was localized, and reulsted in the loss of the ship, as it was broken in two. (as was IJN Mutsu, due to a defective cordite load in her after magazine in 1943.)
I have to correct the information on the HIJMS Mutsu. A stupid Japanese sailor, it is claimed, threw a live cigarette down into the magazine and started a small fire that was not extinguished near exposed powder bags which were not cased in fireproof cans as they were supposed to be. She blew up due to human error.