An online source has the 16"/45 2700 lb shell exceeding 130 mm by about 24.6 km (27,00 yards), and exceeding 150 mm by 26.5 km (29,000 yards). One of the main reasons the American and German shells performed well at oblique striking angles is because of the blunt head shapes. Indeed the reason the 1944 shell performs better is because of more blunt shape than the 39-44 shell. Which brings this into play:alecsandros wrote:... I would add that the only battleship designed to resist 16"/L45 and 16"/L45 gunfire was the Montana class.
Immunity zone was 18 - 31.000yards. Deck protection was a layered system of 38mm upper deck on 19mm STS, and a MAD of 155mm on 32mm STS, with a third, 16mm STS splinter deck. Total thickness of the armor of the decks was an unprecedented (and unmatched since) 252mm. Effective thickness using square root formula gives around 165mm, and that not considering yaw, and decapping effects of the upper 57mm deck (from 2 separate pieces though..)
So we can consider 165mm as the minimum thickness to ensure protection against 16"/L45 at 31.000yards (28km).
USN immunity zones were calculated agaisnt complete, intact penetrations, with the shell in a fit condition to burst, IIRC.
Thus Tirpitz 150mm magazines armor was probably safe out to, maybe 25-26km, while the machinery was safe down to 22-23km or so. However, partial penetrations could still cause haevy damage, and I would estimate that those could occur at ranges 5-10% smaller.
Because of yaw, that more ideal factor of the blunt shell head digging into homogenous armour goes out the window, and the performance enhancement of the blunt head shape is not as significant.Thorsten Wahl wrote:...but one has to expect some additional protection by the special arrangement of the armor.
With quality homogenous armour, partial penetrations don't really happen; it either fully penetrates or no penetration occurs.