1) The block coefficient (CB) is the ratio of the underwater hull volume of a ship at a particular draft to the volume of a rectangular prism (the circumscribing prism) of the same length, breadth, and draught as the ship.
CB = V/(L x B x T)

2) The midship section coefficient (CM) is the ratio of the area of the underwater midship section (Am) of a ship at a particular draft to the area of a rectangle (the circumscribing rectangle) of the same breadth and draught as the ship.
CM = Am/(B x T)

3) The waterplane coefficient (CWP) is the ratio of the area of a ship’s waterplane (AWP) to the area of a rectangle (the circumscribing rectangle) of the same length and breadth as the ship.
CWP = AWP/(L x B)

4) The longitudinal prismatic coefficient (CP) is the ratio of the underwater hull volume of a ship to the volume of a prism with length equal to the ship's and cross-section area identical to the midship section. In other words, the prismatic coefficient is equal to the block coefficient (CB) divided by the midship section coefficient (CM).
CP = V/(Am x L) = CB/CM

Bismarck simmulation, need physics data

Posted: Fri Nov 19, 2004 7:33 pm

by OldMan

Have you any data example of these values for some BB from WW2? I am currently developing a computer simulator of Battleships. I am in need of some data to correct simmulate Bismarck and Tirpitz ships. Any information on mass distribution, center of gravity would be very helpful to achive a realistic physics simmulation of these ships.

Also simmilar information about other BB would be useful.

Here you have Bismarck's data at the "empty ship as completed condition". Perhaps others can provide additional information on other battleships.

· Ratio length/beam: 241.5/36 = 6.71
· Ratio beam/draught: 36/9.33 = 3.85
· Ratio draught/depth: 9.33/15 = 0.62
· Ratio length/depth: 241.5/15 = 16.10
· Block coefficient: 0.55
· Midship coefficient: 0.97
· Waterplane coefficient: 0.66
· Prismatic coefficient: 0.57
· Metacentric height (GM): 4.00 meters at 47,200 metric tons.

But keep in mind that these figures change depending on the ship's displacement at a particular time.

Posted: Fri Nov 19, 2004 9:10 pm

by OldMan

Thank you very much. These will be very helpfull. As soon as I have a reasonable simmulation of the Bismarck I will post it here.

I am building a simmulation that takes into account the weight distribution and different boyance forces according to hull submersion. But the hardest thing is to find out information about mass distribution in ship. The GM data you gave me is very helpful.