Hydrostatics data

Rhino
1

Hi,

The answer of the Hydrostatics Center of Buoyancy and the Volume Centroid is little different. Also in Hydrostatics give an space in the “y” value. This 's a old bug that may be in 9WIP could be solved.

Simple example

Hydrostatics.3dm (42.7 KB)

Hydrostatics:
Volume Displacement = 10
Center of Buoyancy = 1.5, -8.88178e-17, 0.5
Wetted Surface Area = 34
Waterline Length = 8
Maximum Waterline Beam = 4.4
Water Plane Area = 35.2
Center of Floatation = 1.5, 1.07237e-16,1

Volume = 10 (+/- 1e-09) cubic meters
Volume Centroid = 1.5,-7.77156117e-17,0.5 (+/- 1e-09,3.3e-16,1e-10)

2

I don’t really see the difference between both methods. e-17 is such a small number… it’s even in the tolerance +/- 3.3e-16

3

It might also be worth double-checking that the hull geometry is completely closed and free of tiny gaps or overlapping surfaces. I’ve seen hydrostatics calculations give odd results when the model wasn’t perfectly watertight, even though it looked fine visually.

4

These differences are totally irrelevant, and result from rounding errors in the calculations.

5

I’m referring mainly to the “Y”&“Z” values, where there is a blank space. If you want to place a point at those coordinates, you can’t just copy and paste the value shown.

Center of Buoyancy = 1.5, -8.88178e-17, 0.5

Must be:

Center of Buoyancy = 1.5,-8.88178e-17,0.5

6

Hi -

Thanks. This was filed as RH-96576 Hydrostatics: Center of Buoyancy coordinate has a space between X and Y values, preventing copy-paste as a point in Rhino
-wim

7

I’m glad they’re going to fix this bug, which has gone unresolved for so long.

8

RH-96576 is fixed in Rhino 8 Service Release 34