Search found 882 matches

by Bill Jurens
Wed May 02, 2007 3:17 am
Forum: Bismarck General Discussion
Topic: Bismarck: Scuttled or Sunk?
Replies: 206
Views: 84675

Armor Penetrations, etc.

The Ballard expedition never really got a close look at the conning tower of Bismarck, primarily because he was towing a sled which obtained mostly vertical or near vertical views while the real damage was on the sides. There are at least two heavy caliber hits on the conning tower. They did not pen...
by Bill Jurens
Fri Apr 27, 2007 2:02 pm
Forum: Bismarck General Discussion
Topic: Bismarck: Scuttled or Sunk?
Replies: 206
Views: 84675

Pointer errors, etc...

In response to the two previous questions: The "pointer" in this context can be either human or automatic. In any case, there will be some error involved in firing at exactly the right time while the gun is moving vertically, both due to delays in the sensors and the mechanisms. Exactly wh...
by Bill Jurens
Fri Apr 27, 2007 4:51 am
Forum: Bismarck General Discussion
Topic: Bismarck: Scuttled or Sunk?
Replies: 206
Views: 84675

Dispersion in height

It is very difficult to hit a target close aboard with a big gun when the ship is rolling. Some "back of the envelope" calculations might help. Assume that the ship is rolling 5 degrees to each side and that the period of roll is 12 seconds. This corresponds to an average roll rate of abou...
by Bill Jurens
Wed Mar 07, 2007 2:31 pm
Forum: Naval Technology
Topic: Hood explosion
Replies: 10
Views: 6075

Forward Magazine Explosion?

There was no forward magazine explosion on Hood. The forward hull failure was due to hydrostatic implosion.

Bill Jurens.
by Bill Jurens
Thu Mar 01, 2007 5:17 am
Forum: Naval Technology
Topic: Bismarck and Titanic
Replies: 10
Views: 11126

Titanic displacment

It is quite easy to get confused with displacements, as they are often defined in unusual ways, both in merchant ships and warships. If one takes the product of Titanic's length, beam, and draft, one gets the displacement of an equivalent prism in cubic feet. Dividing this by 35 gives displacement i...
by Bill Jurens
Thu Feb 08, 2007 4:42 am
Forum: Bismarck General Discussion
Topic: Bismarck and her contemporaries
Replies: 1296
Views: 215022

hits on armor belt, etc.

There has been some discussion here regarding the number of large caliber hits on Bismarck's armor belt(s). As someone who has spent about sixty hours actually looking at the wreck, often with particular reference to the issues in question, I feel confident in commenting as follows: 1) Someone sugge...
by Bill Jurens
Tue Feb 06, 2007 11:57 pm
Forum: Naval Weapons
Topic: Bismarck's Vo measuring system.
Replies: 12
Views: 6690

Instrumented barrels

Instrumented barrels would be of very little use shipboard, as all of the information which they can deliver, e.g. loss of velocity vs Effective Service Rounds, etc., is much better obtained at the proving ground. There would be no point -- or almost no point -- in feeding I.V. information obtained ...
by Bill Jurens
Tue Feb 06, 2007 2:47 am
Forum: Naval Weapons
Topic: Bismarck's Vo measuring system.
Replies: 12
Views: 6690

Instrumented barrel

The reference in the AKVS test is evidently to what is normally called an 'instrumented barrel', i.e. a gun tube that has been drilled at intervals in order to allow the insertion of pressure gages that can give pressure vs time and pressure vs position along the bore and/or contacts that can detect...
by Bill Jurens
Sat Nov 11, 2006 5:17 pm
Forum: Naval Technology
Topic: Effective battle ranges
Replies: 18
Views: 8984

"As I recall, some of the people at Dahlgren figured it was when the angle of depature exceeded approximately 15* ... in the case of the German 38cm, this is also the range of angle of departure (15-20*), with the least possibility of scatter. " I would be interested in finding out where ...
by Bill Jurens
Fri Nov 10, 2006 6:10 am
Forum: Naval Technology
Topic: Effective battle ranges
Replies: 18
Views: 8984

Danger Space/range

For what it is worth, the USN considered 'long range' to be where the angle of fall exceeded 30 degrees, and/or less than one hit could be assumed per salvo. This, incidentally, was one reason why the 12-gun BBs were seen to have a longer effective range than the 8-gun BBs...

Bill Jurens.
by Bill Jurens
Thu Nov 09, 2006 5:41 am
Forum: Bismarck General Discussion
Topic: Re: "If 15" shell had exploded in POW Bridge"
Replies: 32
Views: 12918

Effects of Single Hits...

George Elder wrote this on this thread some time ago, and I just stumbled upon it now, more or less by accident. My reply is at the very bottom, after asterisks... Bill Jurens Hi Bill: I am having a bit of trouble with this notion: "In general, a single hit forward (or, for that matter, anywher...
by Bill Jurens
Sat Oct 21, 2006 3:42 am
Forum: Naval Technology
Topic: Bismarck class turret protection
Replies: 74
Views: 57139

Hoyer Document

I've seen a number of references to "Hoyer", etc. on this thread. Can I get more information on the name and availability of the original document?

Bill Jurens
by Bill Jurens
Tue Oct 17, 2006 10:28 pm
Forum: Bismarck General Discussion
Topic: Who really sank the Hood? Bismarck or Prinz Eugen?
Replies: 45
Views: 87191

Magazine explosion

I don't understand why such a programme would have you involved if they ignore your expert opinion - what would they have to gain? Whether the forward magazine exploded or not is surely academic to the fact that Hood sank." Well, frankly that somwhat baffles me, too. I have expressed opinions ...
by Bill Jurens
Fri Oct 13, 2006 5:24 pm
Forum: Naval Technology
Topic: Iowa Class real performance
Replies: 67
Views: 34348

Homogeneous armor

Dave Saxton wrote: "I'm finding the homogenous predictions for penetration fall short of predictions for face hardened armour. For example striking at 460 mps at nearly right angles the amount of homogenous armour penetrated (my curves included) is predicted to be about 13% less than the curves...
by Bill Jurens
Fri Oct 13, 2006 5:43 am
Forum: Naval Technology
Topic: Iowa Class real performance
Replies: 67
Views: 34348

More penetration

Your results match my calcs almost exactly. A range around 14600 meters would seem to be near the optimum situation. ORD SK 78841 predicts a limit velocity of 1942 f/s, i.e. c. 591 m/s, and the impact velocity is at that range, picked quickly off a graph -- is about 575 or 580. About 98% as you note...