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by dunmunro
Sat Dec 13, 2008 1:21 am
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

. If the Bismarck could not attain speed requirements at operational displacements, he would have known about it, yet he recorded in his book that the Bismarck did 30 knots during the trial period. If they emptied ship just to make speed runs, then a lot of people would have known about it, and I c...
by dunmunro
Fri Dec 12, 2008 11:58 pm
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

So at DS Bismarck's Panzerdeck was below the waterline? Bismarck's hull depth was 15 meters. Working from drawings, I estimate that the armoured deck was 4.89 meters from the weather deck, or located at the WL at 10.1 meters draft. At DS Bismarck Displaced ~48000 tonnes with a draft of ~9.6 meters,...
by dunmunro
Fri Dec 12, 2008 11:13 pm
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

This site: http://www.schlachtschiff.com/kriegsmarine/schlachtschiff_bismarck/technik/allgemein.asp lists Bismarck's draft at 10.55 meters at 53165 tons, which was her maximum displacement with all fuel tanks full. So again, if we work backwards, we get: immersion per cm = 1055cm @ 53165 tons = 50.3...
by dunmunro
Fri Dec 12, 2008 7:22 pm
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Bismarck Speed3

It may fit the made up hypotheticals, but it doesn't fit the recorded data from the October 29th run. Did you notice that John lists the immersion factor of +57.3? That fits the hard evidence. You need to recalculate based on this fact. A draught of 10.2 meters (at only about 50K?!) and the immersi...
by dunmunro
Fri Dec 12, 2008 10:24 am
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

This site:
http://www.schlachtschiff.com/kriegsmar ... ntrieb.asp
gives the following data:

138000shp = 29 knots at 43000 tonnes.

which fits my curves above fairly well.
by dunmunro
Fri Dec 12, 2008 9:36 am
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

You really have to go the other way, and determine the draft at deep displacement and work backwards, but we have to recalculate the stated immersion/cm which works out to 48.437 tonnes/cm Bismarck's draft at 49406 tonnes = 10.2 meters. so we subtract 170cm from this @ 48.437 tonnes/cm = 8234 tonnes...
by dunmunro
Thu Dec 11, 2008 11:53 pm
Forum: Hypothetical Naval Scenarios
Topic: Japanese Invasion US mainland
Replies: 63
Views: 8882

Re: Japanese Invasion US mainland

Wisely, the USA signed a defense agreement with Canada, obligating the Canadian Army to come to the USA's assistance in the event of an invasion. Doubtless, this was a major deterrent to the Japanese... :wink:
by dunmunro
Thu Dec 11, 2008 11:03 pm
Forum: Bismarck General Discussion
Topic: Bismarck trapped
Replies: 135
Views: 10695

Re: Bismarck trapped

I would second Tommy303's suggestions, and also recommend a detailed reading of Bismarck's, PE's and Tirpitz's war diaries here: http://www.kbismarck.com/archives/index.html and the all the data here: http://hmshood.com/history/denmarkstrait/resource.htm and this site is an excellent introduction to...
by dunmunro
Wed Dec 10, 2008 4:50 am
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

obviously the other possibility is the draft is wrong. That's possible but I wonder how Bismarck's engineers and navigators were ever able to predict her performance, since apparently even the most basic data is filled with contradictions? Here's a crude graph that I prepared showing what I believe...
by dunmunro
Wed Dec 10, 2008 3:24 am
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

Now Mr Rico suggests that Bismarck's displacement was substantially higher than 42000 tons on 29.10.40, and this seems reasonable What I say is that the day of that speed run the Bismarck was loaded with 6,285 m3 fuel oil and 337 m3 feed water according to the KTB, and that equals to a displacement...
by dunmunro
Tue Dec 09, 2008 11:20 pm
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

Trying to extrapolate data from different ships, such as Richelieu, or Vanguard, and so forth, and applying it to a totally different ship results in a faulty comparison, and is therfore of little value in correctly assessing Bismarck's speed data. Besides, such guesstimates are not needed, because...
by dunmunro
Tue Dec 09, 2008 2:28 am
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

Here's some data from Richelieu: LWL 793 ft, Beam 108 ft, L/B =7.34 power needed for a given speed at a given displacement: knots/40243/44277/% increase= 10% 29/105540/116385/10% 30/119345/133155/11.5% 31/138085/151695/10% so we have a 10% increase in displacement requiring a 10% increase in power. ...
by dunmunro
Mon Dec 08, 2008 5:49 am
Forum: Bismarck General Discussion
Topic: Bismarck Speed
Replies: 624
Views: 37762

Re: Holland Shadows Bismarck Instead

Axis BBs gives these numbers on page 304: Bismarck, Aug 1940/Tirpitz Feb 1941 Light ship: 38992 tons/38915 tons (all in long tons) Design: 44734/44755 Full load: 48626/48648 Battle load: 49609/49628 Tirpitz at 163000 shp = 30.8 knots at 49000 tons? Gneisenau at 160000 shp = 30.7 knots at 37000 tons?...
by dunmunro
Mon Dec 08, 2008 2:51 am
Forum: Bismarck General Discussion
Topic: Holland Shadows Bismarck Instead
Replies: 75
Views: 46272

Re: Holland Shadows Bismarck Instead

Hello tnemelckram, I read your scenario and I think Hood and POW would be able to shadow Bismarck and PE but I have my doubts about the approach of Tovey's force. I'm not sure if KGV and Repulse can intercept Bismarck if she isn't slowed first. Maybe I'm wrong but I've looked at some charts and it ...
by dunmunro
Mon Dec 08, 2008 2:49 am
Forum: World War II
Topic: Don't be fooled about the Tiger
Replies: 115
Views: 10742

Re: Don't be fooled about the Tiger

For every Sherman Firefly the Germans had their own Tank Killers that make any US armour obsolete. An example is the Jagdpanzer IV or the famous Jagdpanther (a superb design that makes the Firefly look like... a firefly) , the most incredible Jagdtiger based upon a Tiger chasis (can you image the l...