by delcyros » Mon Feb 28, 2011 4:56 pm
5.91in firing on HMS PRINCE OF WALES would not have used APC but nose- or base fused HE instead. This is prooven by Unterlagen zur Bestimmung der Hauptkampfentfernung und Geschosswahl. Such a shell would be unlikely to leave much traces on the thick cementated main belt or other, face hardened structures of more than 4in thickness.
However, there is -in my mind- some liklyhood that one or both portside strikes aft on PRINCE OF WALES are rather 5.91in HE base fused than 8in APC/base fused HE. There is the account of Jaspar, who as the go of PRINZ EUGEN states:
"I observed two portside strikes, which again were fired by BISMARCK´s secondary". In fact, knowing the german original, this is a minor mistranslation. The correct translation would emphasize the doubt expressed by Jaspar because both ships targeted PoW:
"I observed two portside strikes, which may have been fired by Bismarck´s secondaries".
The after action damage evaluation on HMS PRINCE OF WALES considered these two hits on the far waterline aft to be either 5.91in or 8in, thus it was found to be impossible to assess the damage to either calibre in a definite way. I don´t know when authors started to attribute them exclusively to 8in, though, but it happened.
Some evidence comes from the delay action of these projectiles. Both were rather short delay, as prooven by the short distance travelled by them before exploding. In fact, both projectiles traversed just enough to completely penetrate. An 8in APC using nominal 0.035 sec. fuse delay is likely to pass a lot more distance before blowing up at the given striking velocity (=1550 to 1700 fps) corresponding to the given range of 14,000 to 16,000 yard. Most likely is a distance of 50 to 60 ft for anything close to nominal fuse delay. A nose fused projectile has to be excluded in any case, they were instantiously fused and would detonate completely before the projectile´s nose would make contact with the outer shell plate. Thus only APC or base fused HE is possible.
The base fused HE has a variable delay element, which ranges from non delay (almost instantiously, ca. 0.003 sec. to 0.006 sec) to 0.01 sec., 0.025 sec and 0.035sec. The corresponding distance travelled is for a striking velkocity of 1000 to 1060 fps is much better fitting the damage report (=5ft; 10ft; 26ft or 36ft max).
Further evidence can be assembled by assessing the damage picture much like Rob Lundgren did with SOUTH DAKOTA in it´s engagement with KRISHIMA. It was always considered that these two hit´s were blowign up low order, but authors are forced to this explenation in case You attribute both hits to 8in APC / 8in base fused HE. It´s not necessary to explain them as low order objects if You really consider 5.91in base fused HE, a much more likely alternative in my personal opinion.
Finally, while the entry holes have dimensions largely corresponding to 8in Projectiles, this in my mind rules 8in out. It requires rather thick armour plating to ensure just calibre sized holes in trials conducted 1908 to 1912 from a number of RMA sources. Otherwise the entryhole is always a lot larger than the projectile diameter. In 1912 this was one of the reasons of the retention of german 100mm KC belts at the GK´s far aterline end belts, they deliberately wanted an as small as possible entry hole for calibre penetrations.It was considered that a KC plate thickness of at least 1/3 cal. was required to ensure cal. sized holes. There was, however, little plating and armour engaged by these two hits on the far waterline aft.
Then again, it´s only an interpretation made by myselve based on aviable evidence, not a definitive case for one or two 5.91in hits.
