Search found 159 matches

by RobertsonN
Wed Feb 27, 2019 8:05 pm
Forum: Naval Weapons
Topic: Shell hits v armour
Replies: 4
Views: 778

Re: Shell hits v armour

Paul, I do not know if target motion at the time of impact was a significant factor in armor penetration, but this question seems to have escaped detailed analysis up to now. Often, tthe advantage of light was decisive, such as at Colonel. This advantage involved chance, that of the relative locatio...
by RobertsonN
Mon Feb 25, 2019 7:55 pm
Forum: Naval Weapons
Topic: Shell hits v armour
Replies: 4
Views: 778

Re: Shell hits v armour

I think you are correct in saying that chance could play a big role in naval engagements. The form of the hull, pitch, roll and yaw all affect the overall angle of incidence. The striking velocity will depend on the nominal muzzle velocity, state of wear of the barrel, charge temperature, relative v...
by RobertsonN
Fri Feb 22, 2019 7:30 pm
Forum: Naval Weapons
Topic: Damage to US AP shells
Replies: 0
Views: 95

Damage to US AP shells

Recently I read the excellent piece about shell damage on Nathan Okun's website, which I recommend. Since then I have come across two accounts of damage to US AP shells that hit Jean Bart that are somewhat at variance with Mr Okun's conclusions. Mr Okun says that because of their sheath hardening US...
by RobertsonN
Tue Feb 12, 2019 8:04 pm
Forum: Naval Technology
Topic: Damage Control Question
Replies: 2
Views: 240

Damage Control Question

On p. 61 of The Littorio Class by Bagnasco and de Toro there appears: 'Each zone [of seven] was connected directly by telephone to the two damage control (or floatation centres): the main centre at frame 144 ... and the secondary centre located near the after propulsion spaces. The damage control ce...
by RobertsonN
Sun Nov 25, 2018 11:57 pm
Forum: Hypothetical Naval Scenarios
Topic: Vanguard and Bismarck
Replies: 84
Views: 20658

Re: Vanguard and Bismarck

As I understand the main reason allies went to single deck armor plate was to defeat bombs, not shells. Both. Reason was simple. With increasing power of shells allies goes to conclusion that detonation of shells had to keep out of ship. Multilayer protection was designed in such way to force shell...
by RobertsonN
Thu Nov 22, 2018 8:17 pm
Forum: Bismarck General Discussion
Topic: Bismarck analysis
Replies: 24
Views: 8934

Re: Bismarck analysis

In regard to some of the points made in post 1 it can be said that they are wrong. (a) The Bismarck was not intended for operations in the North Sea but for cruiser-type warfare in the North Atlantic. Had it been designed for the North Sea then it would not have had a fuel stowage of about 7450 mt. ...
by RobertsonN
Mon Nov 19, 2018 10:40 am
Forum: Bismarck General Discussion
Topic: 38 cm shells
Replies: 60
Views: 25260

Re: 38 cm shells

In Warship 2018 there is a detailed analysis of the Battle of the River Plate by Alan Zimm and a detailed analysis of the damage suffered by Graf Spee by Bill Jurens. Mr Zimm compares the action with US expectations according to the NWCMR and British rules. The main armament of Graf Spee scored more...
by RobertsonN
Sun Nov 18, 2018 5:28 pm
Forum: Bismarck General Discussion
Topic: 38 cm shells
Replies: 60
Views: 25260

Re: 38 cm shells

The 38 cm SKC/34 was the most accurate German heavy gun: it had the lowest dispersion by some margin. In gkdos100, vol. a, there is a graph at the end showing 50% longitudinal dispersion curves versus gun elevation (less than the angle of fall) for weapons from 15 cm upwards. Over 7 deg the 38 cm SK...
by RobertsonN
Sat Sep 16, 2017 7:23 pm
Forum: Naval Technology
Topic: Montana class ships
Replies: 9
Views: 4713

Re: Montana class ships

Yes, this does look more plausible in thinking about it further. There was an advantage of 1100 yds, which would have needed about an inch of protection. The Americans in their calculations added 0.7 times the strength of secondary protection to the main protection so here the hull skin in Iowa adds...
by RobertsonN
Sat Sep 16, 2017 4:18 pm
Forum: Naval Technology
Topic: Montana class ships
Replies: 9
Views: 4713

Re: Montana class ships

A point about Montana's protection scheme which puzzles me. I have a copy of a document listing official IZ values for US battleships (C-BB/S1-1 of 13 July 1942) against 16 in 2240 lb shells with an MV = 2520 fps. The inner limit for BB 61 (Iowa) is given as 17600 yds and that for BB 67 (Montana) as...
by RobertsonN
Tue Jan 14, 2014 7:54 pm
Forum: Naval Weapons
Topic: Armor penetration of HE shells
Replies: 7
Views: 6418

Re: Armor penetration of HE shells

Regarding the extrahard Wh splinter armor for, e.g. splinter bulkheads, was this material classified as Wh (UTS 85-95 kg/mm2) or was it Wotanstarrheit as used in AA directors or something else? The finding that base-fused HE had a splinter penetration effect intermediate between nose-fused HE and AP...
by RobertsonN
Sun Nov 18, 2012 12:56 am
Forum: Hypothetical Naval Scenarios
Topic: Hoods armour
Replies: 17
Views: 3098

Re: Hoods armour

According to Nathan's study, British 1920s cemented armor had 85% - 90% of the resistance to perforation of British post 1930 cemented armor, at best ... If this mean the ballistic limit was approximately 10% lower compared to german KCnA, Hoods facehardened armor had about 275mm effective thicknes...
by RobertsonN
Mon Nov 12, 2012 8:41 pm
Forum: Naval Propulsion
Topic: Fuel consumption Bismarck
Replies: 74
Views: 35282

Re: Fuel consumption Bismarck

I would be interested to see endurance curves for these ships with a common auxiliary consumption (say 5 t/day) so that their relative propulsion efficiencies would be discernible. Of course, bigger ships would have somewhat higher auxiliary loads than smaller ones but assuming a constant value woul...
by RobertsonN
Thu Nov 08, 2012 9:00 pm
Forum: Naval Propulsion
Topic: Fuel consumption Bismarck
Replies: 74
Views: 35282

Re: Fuel consumption Bismarck

Just to say I appreciate people posting original documentation regarding trial speeds, ranges and displacements of various ships in this thread. With regard to Thorsten's last post could it be that the normal operating condition in wartime was different in the KM from that in the USN? Namely, did a ...
by RobertsonN
Sat Mar 17, 2012 12:08 am
Forum: Bismarck General Discussion
Topic: Bismarck's fate.
Replies: 34
Views: 9062

Re: Bismarck's fate.

If the ship steadied with the bows pointing north west, perhaps it was worth trying going astern. Unfortunately, with turbines reverse power is small. Perhaps if the original plan to have turboelectric drive had been implemented, with full power possible astern, the Bismarck might have managed to mo...