You have read the account on the BADEN trials, Nikedamius, so why You are unable to understand them needs explenation. They perfectly fit the problems I outlined above.
The trials are the data, the interpretation is what can be questioned in Your part.
I consider terminology a very important thing. If a projectile can pass a plate without beeing able to detonate in proper distance and reliably behind it, it´s not of much use in achieving decisisve results against enemy battleships. In case of the barbette hit, it did not completely penetrate as You imply. It gives contrary evidence, I quote from the report:
Apparently the shell burst when it was two-thirds of its way through the armour and the nose of the shell as far as the shoulder was found inside barbette 23 ft. from outer edge of entry hole.
By any naval teminology standarts, this must be considered a PARTIAL PENETRATION instead of a COMPLETE PENETRATION You, Brown and even the author of the report likes the projectile to be. It did not completely penentrate but burst in holing. A complete penetration requires 100% of the projectile to pass the plate (
US naval nallistic limit, german
Grenzdurschschlag, the british have a similar definition with 3 out of 5 shells in a row making it 100% through), otherwise it´s only partial. You have to be careful in choosing the right definition.
And You can repeat bolding up that the shell that indeed completely penetrated the turret face (100% of it came through but in a blind condition, as I said) was eventually blown up by a guncotton charge, but this has nothing to do with the shell striking this armour. It was blown up later on after the projectile was found blind resting there as a seperate event in order to assess what a high order burst could have done in regards of damage to the interior of the turret. The shell itselve penetrated not in a condition fit to burst, it´s fuse broke.
And then You have to consider opbliquities for these impacts, which are very low for the two cases cited. At obliquity, they failed to even hole the armour. Would an older type of shell have been able to reach these results? Considering that these two tests against heavy armour were carried out such low obliquities when both, the new hard AP-caps and the old soft ones usually work, they probably would have done the same to it, with a higher likelyhood of burst in holing or burst on impact. Neither shell is able to penetrate heavy armour and burst reliably behind. THE BADEN TRIALS DO NOT SUGGEST SUCH AN ABILITY TO THE GREENBOY SHELL.
3 x 15in APC rounds were fired through the 7in battery armor, at least one of which hit and nearly penetrated the 7 3/8 barbette beyond. CPC shells were fired against the decks and caused very severe blast damage. It seems to have been concluded that the new generation of shells would penetrate thick armor and the new fuses would explode them about 40 feet beyond the point of impact. The filling, Shellite in the APC, Trotyl in CPC would explode violently causing severe damage
Ever checked the fuse delay actions of the BADEN trials for APC striking medium armour (this is armour in the thickness range of 0.472 cal. to ~2/3 cal thickness)? They are unpredictable. While the new shell is able to penetrate medium armour in a condition fit to burst reliably, the fuse delay is way to unpredictable and the official report mentions this.
nominal fuse delay for the projectiles with 16D fuse was 0.025 sec.
against 7in:
Round No. 4 (APC) was a 22 deg impact, burst 38 ft. implying 0.025 sec. delay
Round No 11 (SAPC) was 28 deg impact, burst 20 ft, implaying 0.013 sec. delay
Round No.12 (APC light) was 27 deg impact, followed by a low order burst 30 ft. later, implying 0.021sec delay
Round No. 16 (APC) was 18 deg impact, burst 53 ft. behind, implying 0.037 sec delay.
Round No. 2 of 2nd series (SAPC) was 5 deg. to normal, burst 7 ft., implying 0.005 sec. delay
Thus instead of the desired reliable fuse delay, half cal. thickness armour could be reliably penetrated but the fuse delay varied from nearly instantious (Type 16ND non delay fuse action also showed 6 to 10ft delay, implying a minimum delay time of 0.005 to 0.006 sec.) to ultra long 0.037 sec. and the impact condition does not explain for this variance.
Now look for impacts on 10in armour:
You quoted:
Round No. 15, striking it at 14 deg and burst 38ft. behind, implying 0.035 sec delay
but why don´t You also consider this one as well?
Round No. 8, striking it at 18 deg and burst 7ft behind, implying 0.006 sec delay
Again the variance ranges from instantious delay action to longer than desired delay action at almost identic conditions of impact. That Brown states that the new GREENBOY shell would detonate 40ft from impact is an error, which can be disprooved by the analysis of the trials conducted on SMS BADEN (Round No. 2, No. 8, No. 11, No. 12 No.16). Fuse delay action of the 16D fuse used in these rounds was far from statisfying and unpredictable in it´s length. It may have been basically non-delay in one case and to long in the next.
How does the medium thickness armour tests compare with Jutland?
The old shells judging from Jutland´s experience showed at least 2 similar events: a 15in APC defeating the barbette armour of DERFFLINGER and burst directly behind, which was 2/3 cal. thickness (10.23in). The condition of impact and result are similar to the Round No. 8 from the BADEN trial. And another 15in APC defeating the upper side belt of VON DER TANN and bursting a distance behind, which was about half cal. thick plate -most of the time, however, older shells burst on impacting medium armour thickness ranges.
So if there is an improvement of the new shell, it does not necessarely mean that the armed GREENBOY APC had the capability to go up high order behind heavy armour, even striking at low obliquities. Against medium armour, the new APC can penetrate at medium and low obliquities but the variance in delay action is larger than desired, one third of the projectiles had to short fuse delay, one third had to long a delay.
Thus the real improvement of the new APC was in the medium thickness armour range, some area when older shells from time to time also achieved good results. Fuse delay, however remained to be unpredictable until the late 20´s. Older shells burst on armoru because of rapid compression of the charge, though, before punching through it even if penetration would have been possible for a dud.
Addendum:
I must add that my term "disappointing" with regards to the result is not meant to be a recapture of the contemporary views on the matter. I use it on my own, after reading so much of this projectile and it´s super-abilities (even Nathan Okun stated informally that GREENBOY APC have the ability to defeat near calibre thick armour and burst reliably behind at high obliquity according to those trials) that I found the results as reported in ADM 186/251 disappointing. The contemporary view was that the fuses were working with disappointing reliability but that the projectile had progressed far enough not to burst on impact as was the case earlier (caused by a wrong british specification what the projectiles had to fullfill, not because Britain was unable to produce better shells).