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

The Wreck of DKM Bismarck − A Marine Forensics Analysis
blades on first, with slotted bolt holes to allow the propeller to be adjusted slightly for maximum
efficiency, then − once the best position was found from tests in the Baltic in the fall of 1940 −
manufactured and installed solid, one-piece propellers to replace the experimental ones.
In his recollection of leaving the center engine room after placing scuttling charges, LT
Gerhard Junack advised author Bill Garzke, Jochen Brennecke 19 , and Dr. Oscar Parkes 20 that he
left the engine room around 1010 with shining lights and a slowly turning shaft. For that shaft to
keep turning, either the coupling in the shafting was parted by the jamming of the rudder into the
center propeller, the keys holding the center propeller to the shaft failed in shear, or the propeller
was able to keep turning once the intact portions of the three blades were free of the rudder
structure.
Bismarck underwent an extensive stay in the Blohm & Voss Shipyard from December
1940 until March 5, 1941. We have seen no photographs taken of the propellers during that stay
− views taken in July 1940 cannot answer the question as to what was fitted when the battleship
sortied for combat. It is very probable that single-piece propellers were fitted during that final
availability. The dramatic discovery of the embedded blade in the rudder gives a new insight
into the condition of the propellers and rudders at the time of the sinking of the battleship. Bolted
blades are used today in controllable pitch propellers in FFG-7 and DDG-51 class ships, with
hefty bolts.
Until the James Cameron May 2002 Expedition, the seriousness of damage to the rudders
was unknown. Photography of the underside of the hull revealed that the rudder stock for the
port rudder had fractured. Did the force of the torpedo explosion bend this rudder, which was
already canted outboard about 8 degrees, further to port causing it to contact the port propeller?
The answer to that question is “no”, because the port propeller shows no sign of damage. Did the
subsequent slamming of the hull in the heavy seas lead to the failure of the rudder stock through
the forces of accelerated fatigue? The answer can never be known with certainty.
In the meantime, the light cruiser Sheffield reported that Bismarck was heading to the
northeast at a slow speed. Sea conditions hampered the Sheffield’s efforts to determine the nature
of the damage caused by the torpedo attack. Due to her port turn, Bismarck closed range and
then opened fire with her 380-mm guns in a brief engagement. Before the cruiser could open the
range, Bismarck’s gunfire disabled Sheffield’s radar, caused minor fragment damage, and
inflicted several casualties. This incident reminded the British that the Bismarck remained a
formidable adversary, even if damaged and apparently unable to escape.
Captain Lindemann ordered the ship to be slowed so that assessment of the damage in the
stern could begin. He ordered two of his best damage control personnel, LT Gerhard Junack and
LTJG Hermann Giese, to the area to determine the nature of the damage and to commence the
needed temporary repairs. Their efforts had to be halted at times, as Admiral Lütjens, Captain
Lindemann, and CDR Oels wanted reports regarding the efforts to restore the steering function.
Oels also sent two divers to the area to determine what damage occurred in the steering gear
rooms. Lowering divers over the side was discussed, but sea conditions were causing the stern to
rise and fall with such force that an accurate inspection was impossible and might have caused
the death of the divers,as well. Attempts to steer the ship with the propellers were unsuccessful,
due to the position of the starboard rudder in the race of the center propeller. Bismarck was
doomed.
19 Schlachtschiffe Bismarck, Kohlers Verlag, 1960, page 361.
20 Dr. Oscar Parkes’ paper on Bismarck in the 1948 Transactions of the Royal Institution of Naval
Architects. Dr. Parkes did not name the source except as a survivor.
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