Search found 200 matches

by RobertsonN
Mon Apr 20, 2020 10:23 pm
Forum: Bismarck General Discussion
Topic: Comment on Rebuilt US Battleships
Replies: 13
Views: 3027

Re: Comment on Rebuilt US Battleships

As far as Scharnhorst was concerned what you say is true. But use of the Scharnhorst layout in Bismarck would have allowed for the distance from the hull side to the torpedo bulkhead to have been increased to up to 7.7 m (it could have been less than this had the width of the boiler rooms and/or the...
by RobertsonN
Mon Apr 20, 2020 5:44 pm
Forum: Bismarck General Discussion
Topic: Comment on Rebuilt US Battleships
Replies: 13
Views: 3027

Re: Comment on Rebuilt US Battleships

I don't know much about CBs. But the figures given by Friedman do not give the normal displacement of Moltke. Furthermore, he gives the draft of Moltke as being 9.2 m at normal displacement. The generally accepted figure was 8.2 m (given in Griessmer, for example). The value for CB required to give ...
by RobertsonN
Mon Apr 20, 2020 4:52 pm
Forum: Bismarck General Discussion
Topic: Comment on Rebuilt US Battleships
Replies: 13
Views: 3027

Re: Comment on Rebuilt US Battleships

Yes. I am aware that Raedar thought that for the first time in Bismarck the individual machinery compartments were of an adequate size. The boiler room subdivision of Scharnhorst was considered poor when this layout was one of a number considered for Bismarck in the design stage. That was certainly ...
by RobertsonN
Sun Apr 19, 2020 8:08 pm
Forum: Bismarck General Discussion
Topic: Comment on Rebuilt US Battleships
Replies: 13
Views: 3027

Re: Comment on Rebuilt US Battleships

The formula for displacement includes the product CB x B where CB is the block coefficient and B the beam. It follows that B can be traded off against CB. Friedman gives a CB of 0.55 for Bismarck, which gives about the correct figure for the normal displacement from the formula in metric units of D ...
by RobertsonN
Sat Apr 18, 2020 10:31 pm
Forum: Bismarck General Discussion
Topic: Comment on Rebuilt US Battleships
Replies: 13
Views: 3027

Comment on Rebuilt US Battleships

This post is based on two of Friedman's books: (1) Battleship Design and Development 1905-1945 and (2) US Battleships. On p. 94 of (1) there is a plan view of the hull subdivision of Idaho (1925). This had a mixed system of subdivision, mostly having main compartments divided into three by two longi...
by RobertsonN
Tue Oct 22, 2019 7:12 pm
Forum: Bismarck General Discussion
Topic: bismark-after torpedo hit
Replies: 208
Views: 35824

Re: bismark-after torpedo hit

Under-bottom torpedo hits, if they can be arranged (now fairly easy, in the 1940's very difficult) are indeed, potentially lethal regardless of side protection. Bismarck's side protection system was certainly not inept in concept, but it certainly wasn't perfect either. The biggest problem lie in t...
by RobertsonN
Sat Aug 31, 2019 9:34 am
Forum: Bismarck General Discussion
Topic: It's up to you
Replies: 3
Views: 1405

Re: It's up to you

Over on the NavWeaps Forum this kind of explosion used to be fairly regular. Each time followed by a silence for a few days. Then one or two people made posts and soon things were back to normal,

Neil Robertson
by RobertsonN
Sun Aug 11, 2019 4:05 pm
Forum: Bismarck General Discussion
Topic: Battleship Bismarck: A Design and Operational History
Replies: 59
Views: 20140

Re: Battleship Bismarck: A Design and Operational History

I am now close to the end of this book, having started on June 25. The authors remark that there was difficulty in damaging Bismarck at very close range because of the sea state. Waves were six to eight meters high. This would have meant that under a range of 5000 m, the last 100+ m of the shell tra...
by RobertsonN
Sat Aug 03, 2019 1:07 pm
Forum: Bismarck General Discussion
Topic: Battleship Bismarck: A Design and Operational History
Replies: 59
Views: 20140

Re: Battleship Bismarck: A Design and Operational History

My main criticism of this book so far in reading it has been the lack of German evaluations of the ship, particularly in relation to foreign ships. I have now come across some comment on this subject, although it is brief and made in passing in the operational history sections. The authors make no c...
by RobertsonN
Mon Jul 29, 2019 4:05 pm
Forum: Bismarck General Discussion
Topic: 3-shaft propulsion
Replies: 128
Views: 103825

Re: Battleship Bismarck: A Design and Operational History

Three shafts weigh less than four. Breyer in Marine Arsenal No. 2, p. 6, gives the weight of the shafts and propellers in Gneisenau as 366 mt. So one shaft with its propeller weighed about 120 mt,

Neil Robertson
by RobertsonN
Fri Jul 26, 2019 10:24 am
Forum: Bismarck General Discussion
Topic: Battleship Bismarck: A Design and Operational History
Replies: 59
Views: 20140

Re: Battleship Bismarck: A Design and Operational History

I did have a look in my copy of Axis Battleships again and can confirm that this is the more complete book as far as the design of the ship is concerned. Mind you, I did notice one glaring contradiction in it. It says the armor was intended to provide protection between 20000 and 30000 m. Later on, ...
by RobertsonN
Thu Jul 25, 2019 4:16 pm
Forum: Bismarck General Discussion
Topic: Battleship Bismarck: A Design and Operational History
Replies: 59
Views: 20140

Re: Battleship Bismarck: A Design and Operational History

Another omission in this book is any reference to the post-Jutland German designs for ships of the line and 'fast large fighting ships'. These were mostly of about the same size as Bismarck. While the ships of the line featured the usual sloping armor deck, the fast large fighting ships omitted this...
by RobertsonN
Thu Jul 25, 2019 10:27 am
Forum: Bismarck General Discussion
Topic: Battleship Bismarck: A Design and Operational History
Replies: 59
Views: 20140

Re: Battleship Bismarck: A Design and Operational History

I would agree mostly with this assessment. The book is very strong on the operational story and the wreck. There are many excellent photos of the ship as it is now, mainly taken during the Cameron 2002 expedition. There is a fairly detailed reconstruction of the probable trajectory of the ship from ...
by RobertsonN
Tue May 21, 2019 9:39 pm
Forum: Bismarck General Discussion
Topic: On the Origins of Scaling
Replies: 13
Views: 2359

Re: On the Origins of Scaling

It is often helpful in developing one's own ideas to talk to other people about them as here. Looking at support for the ideas I am putting forward in Gkdos100: For the 38 cm APC sees against KC n/A that the curves are very close together at 90 deg obliquity (normal) are very close together (a diffe...
by RobertsonN
Tue May 21, 2019 8:27 pm
Forum: Bismarck General Discussion
Topic: On the Origins of Scaling
Replies: 13
Views: 2359

Re: On the Origins of Scaling

The scaling effect in going from 15 in to 16 in is likely to be distinctly less than the difference in impact velocity, although it depends a bit on what the range is as the 15 in will slow down more than the 16 in as range increases, reducing that 100 m/s difference. In this example the 15 in proba...