Bismarck Speed

[Ulrich Rudofsky]

The speed trial Blohm & Voss certificate shows that under the test conditions on the official Baltic testing course (a Kriegsmarine installation) BISMARCK made 28.374 knots over the bottom on a measured course under ideal conditions. From a graphic extrapolation B&V certified a maximum speed of 30.1 knots.

No one knows from what primary sources some of the post-war authors got the various other figures from. But unless an OKM document can be found that states otherwise, the B&V document is the only primary source.

(It may also be that the OKM issued false speeds for ships to confuse the enemy.)

Errors do occur and are perpetuated. As recently as 2005, a sailor aboard the USS WISCONSIN told me that she could do 35-38 knots on a good day!!!!

[Tiornu]

Was the speed run performed across an especially shallow mile?

[Ulrich Rudofsky]

Yes. The trial course is at a certain depth and visible distance from land. I have the particulars somewhere buried in another computer. I thought we had that on this site but I can't find. As far as I remember the water was moderately deep, the bottom flat ect.......I will try to find it. Also, the turning radii and loss of speed in power turns were done at this Baltic navy installation. None of the tests were done on the open ocean (auf hoher See). Also the firing range tests were done under good conditions.

[Tiornu]

I'm not sure how they calculate the effect of water depth. Maybe Bill J can give some specifics.

[Ulrich Rudofsky]

In the Kriegschiffbau books by either Handler or Evers there is a detailed description of the course and how deep the water must be etc.....I translated it ......but I can find it right now.......a senior moment of bad memory in the head and computer

[marcelo_malara]

sailor aboard the USS WISCONSIN told me that she could do 35-38 knots on a good day!!!!

So she is not only member of the sacred cows, like my friend Karl likes to say, but of the flying cows too!!!

[Ulrich Rudofsky]

When a Wisconsin cow flies too fast she looks like this: http://www.usswisconsin.org/Collision/collision.htm

[Tiornu]

She looks hungry, like she hasn't eaton in a few days.

[_Derfflinger_]

Ulrich -

Neat pic ... the "Wisky" looks like some mean sea serpent!

Are there any pics of what the other guy looked like?

Derf

[Ulrich Rudofsky]

Yes click on the link above the picture...........there are many photos and the accident report

http://www.usswisconsin.org/Collision/collision.htm

[dunmunro]

Speed - Bismarck versus Scharnhorst/Gneisenau

It is interesting to compare the speeds of Bismarck and Scharnhorst/Gneisenau. The two BCs shared a 3 shaft layout with Bismarck and generally developed the same or more power but displaced about 11000 tons less and had a higher length/beam ratio.
Bismarck/Scharnhorst/Gneisenau

Max Displacement: 50,500/39600 tonnes

waterline length: 241/226M

Beam: 36m/30m

length/beam 6.71/7.53

beam/draft 3.85/3.26

speed based on speed/power curve (Battleships of the Scharnhorst class Koop)

Scharnhorst:
31 knots at 160000shp @ 39000tons
30 knots at 135000shp @ 39000tons
29 knots at 120000shp @ 39000tons
28 knots at 100000shp @ 39000tons

31.65knots on trials (no displacement given)

Gneisenau:
30.7 knots @ 160050shp (no displacement given)
28knots @ 152000shp (no displacement given)

Bismarck 30.1knots @ 150000shp (no displacement given)
Tirpitz 30.8knots @ 163000shp (no displacement given)

Given the results for Scharnhorst and Gneisenau, I find the figures for Bismarck and Tirpitz to be quite unbelievable, unless they were recorded at completely unrealistic displacements.

[marcelo_malara]

Bismarck is longer, which means a higher hull speed: it would be about 36.65 kt for Scharnhorst and 37.84 for Bismarck. That means less resistance at the same speed.

[RF]

Was not the speed of Bismarck properly recorded on its Baltic sea trials?

[dunmunro]

Bismarck is longer, which means a higher hull speed: it would be about 36.65 kt for Scharnhorst and 37.84 for Bismarck. That means less resistance at the same speed.

Yet Bismarck is 11000 tons heavier and has a much lower beam/length ratio. The results of Tirpitz matching Scharnhorst for speed with the same SHP is unbelievably amazing.

[marcelo_malara]

Dunmunro:

I know you love the lenght/beam ratio, we have previousy discussed about it. I am not a naval architect, but I have read quiet a lot about ships, and nowhere have ever read that a lower ratio means a slower ship (reasonably close). In fact I am reading the book The search for speed under sail, by Howard Chapelle (a naval architect), who analizes que evolution of the sail ship from the attainable speed point of view, and he put great emphasis in the buttock lines (lines that intersect the skin at equal distance from the centreline), rise of floors (not applicable in a battleship) and the entrace and run, but very little in the ratio.