The Wreck of DKM Bismarck − A Marine Forensics Analysis 1 The ...

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The Wreck of DKM Bismarck − A Marine Forensics Analysis According to survivors, large cracks appeared in the welded seams in the outboard strakes of the main transverse bulkhead, which was also the forward boundary of Port Boiler Room No. 2 in Compartment XIII. Seawater seeped through these cracks and caused gradual flooding of this boiler room. A damage-control team attempted to seal off these leaks with hammocks, but their efforts only slowed the seepage. The boiler room was back in operation for a short time. Boiler III was lighted, while Boiler IV was salt-contaminated and had to be shut down because there was a real danger of saltwater intrusion into the feed water system. By midafternoon, Boiler III also had to be shut down and the space was evacuated. Fuel from the damaged wing tanks in Compartment XIV was leaking into the sea. Soon after the action with Prince of Wales ended, a damage-control team attempted to seal off the leaks in the 45-mm torpedo bulkhead on the portside in Compartment XIV with hammocks and mating, but their efforts only slowed the seepage into the boiler room. Eventually the boiler room was evacuated after the water became chest deep. Steam from other boilers was rerouted to the turbine in the port engine room. Splinters from the exploding shell also severed a main steam line in the No. 4 Turbo-Generator Room, scalding five of its occupants and necessitating the shutdown of the generators. The Turbo- Generator Room also flooded 12 . The loss of this electrical generating station was not serious, because the power supply of German battleships was so conceived that either the forward or the after station could supply the battle circuit load individually (i.e., the ship had 100% reserve battle load power). The bow flooding, coupled with the displacement of fuel oil in Compartment XIV and subsequent flooding of spaces there, caused the battleship to trim 1.5 meters by the bow, with a three-degree list to port − not nine degrees previously estimated. These hits came around 0605 (after Hood had sunk). The combination of trim and list caused the starboard propeller blades to break the water surface. Soon after the action with Prince of Wales ended, a damage-control team attempted to seal off the leaks in the 45-mm torpedo bulkhead on the portside in Compartment XIV with hammocks and mating, but their efforts only slowed the seepage into the boiler room. Eventually the water was chest deep. There was a real danger of saltwater intrusion into the feed water system. The crew managed to get Port Boiler Room No. 2 temporarily back in operation. Boiler III was back in service, although while Boiler IV was salt contaminated and had to be shut down. By mid-afternoon, however, Boiler III also had to be shut down and the boiler room was evacuated. Shell splinters also passed into double bottom tanks and wing fuel bunkers, causing the eventual flooding of that tankage and contaminating the fuel. These reserve fuel tanks were intended for Bismarck’s consorts. The pump room for them was located outside the armored citadel. In an emergency, of course, this fuel could have been used by the battleship. To retrieve the oil in the reserve oil tanks, the Bismarck’s damage control team devised a plan to run a refueling hose over the main deck to the forward tanks, so the problem was isolation, not rupture of these tanks. Some of the reserve oil tanks could have been holed by fragments caused by this hit in the bow. Fuel leaking into the sea would have flowed along the side of the ship, being mixed by the turbulence in the wake, convincing observers aboard Prinz Eugen that there was oil on both sides of Bismarck's wake. 12 Midshipman Hans-Georg Stiegler, a naval constructor in training, was assigned to the electrical shop. He recalled that this compartment was successfully dewatered the next day. 10
The Wreck of DKM Bismarck − A Marine Forensics Analysis ADMIRAL LÜTJENS’ DAMAGE REPORT TO NAVAL GROUP NORTH Admiral Lütjens’ report to Naval Group North, based on damage assessments by Bismarck’s damage control teams, is most revealing: "Two heavy hits. One in Compartments XIII-XIV with the loss of electrical station 4; port boiler room is taking water, which we can control. Second hit Compartment XX-XXI in the forecastle. Shell entered port, exited starboard above armor deck. Third hit on a boat, of no concern." Most of the port list was due to the flooded No 4 turbo-generator room, the port No. 2 Boiler Room, fuel tanks outboard of these spaces, and some of the port counterflooding tanks in Compartments XIII-XIV. Lütjens’ report about the shell hit forward that exited the starboard side shell and the size of the hole would indicate that the shell did not explode within the ship. However, its penetration through ship structure did create fragments that had sufficient energy to penetrate through the deck structure to the port reserve fuel oil tanks and perhaps the pipe tunnel. The starboard tanks were probably intact. What fuel was left in those tanks would have mixed with seawater and because the exit hole was below the bow wave created by the ship’s forward motion and trim the fuel/seawater mix would exit from the starboard and port side. The flooding of the pipe tunnel and port fuel reserve tanks that were partially empty would also contribute to the port list, which reached about 4.5 degrees. What is significant is that two shells fired at a range of 15,000-16,000 meters by the 356mm guns of Prince of Wales materially damaged Bismarck, leading to the eventual decision to abort the Bismarck’s commerce-raiding mission. It would not be possible to conceal Bismarck’s presence at sea with fuel leaking into the sea. This gunfire damage is important, because it clearly documents the effectiveness of main armament-caliber plunging fire at long range. These are the precise conditions of the earliest part of the final battle on 27 May, but most definitely were not the situation during the latter part of that battle, when Rodney had moved to starboard (firing at low angles of elevation at less than 3,700 meters) and King George V was also firing at close range from port. These two shell hits 13 achieved by Prince of Wales occurred about the time Hood sustained her fatal damage, approximately 0600. Prince of Wales was about 16,000 meters distant at the time, eventually closing to 14,500 meters. Angle of fall of both shells would have been between 12-15 degrees. It is interesting that the descent angle was sufficient to allow one shell which fell short to follow an underwater trajectory, being deflected and substantially slowed by the water, to pass under the armor belt and enter the hull abeam of the bridge. It is unlikely the latter projectile could have crossed the width of the Batteriedeck at that angle of fall, unless it ricocheted off the deck before it exploded against the shell plating (a possibility). The level of the exit hole for the forward shell hit, however, seems to correspond to Zwischendeck level, not the Batteriedeck level. After the engagement with Hood and Prince of Wales, the ship’s engineers suggested slowing Bismarck and heeling the ship once to port and then to starboard and welding on steel 13 An analysis of the gunnery report of Prince of Wales and an extensive correspondence by William Garzke with then-CDR Colin McMullen, the gunnery officer, and LCDR Arthur Skipwith, spotting officer, confirms it was the Prince of Wales (not Hood) that achieved these two hits. Gunners on the new British battleship had only two weeks of gunnery drills, NONE firing live rounds. 11
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