Waterplane
properties are more sensitive to station spacing than are displacement
properties. This is because the shape of the end of a waterplane may
not be well represented when it falls between stations. Longitudinal
KM and LCF are exceptionally sensitive to station spacing.
Transverse stability, which depends on displacement and center of
buoyancy, is relatively insensitive to station spacing.
When the accuracy of waterplane properties is particularly important,
the hull model can be enriched with additional stations. The FILL
command is most useful for this since it uses nonlinear interpolation.
FILL requires Model Converter.
The following run illustrates the effect which station spacing has
on waterplane properties. It uses the FV.GF model which is distributes
with GHS and BHS.
copy c:\ghs\fv.gf fv.gf1
read fv.gf1
report fv.pf
macro g
ghs 4.0, 4.2 ... 9.0
/
.g
fill /maxgap: 2
.g
fill /maxgap: 1
.g
quit
Three graphs of the same hydrostatic properties are produced, the
first is with the original station spacing, the second is with stations
spaced at 2% of the overall length and the third is with stations
at 1% of the overall length. |
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