GHS User Bulletin

HSC heeling moment

In order to find a heeling moment such that the residual area ratio from an initial "roll" angle to RA0 is unity, the HSCmmt macro from the HAXHMMT library can be used. This library is distributed with the HAXHMMT wizard. However the HSCmmt macro can be executed independently of the wizard.

Two parameters are required:

1) The "roll" angle. This is the angle offset from zero where the area integration begins. It should be a positive number for starboard-side heeling. For example, if the given roll angle is 15, the curves will start at -15 and proceed in the positive direction. If the given roll angle is negative, port-side heeling will take place.

2) The initial heeling moment. This is an estimate of the heeling moment and should not be so large that a capsize results. It can be positive or negative regardless of the heel direction, since it will be adjusted as needed.

After finding the HMMT required to make the area ratio unity, the HSCmmt macro produces a righting-arm curve to verify its finding.

Since the HSCmmt macro makes use of LIMIT commands, it will nullify any existing LIMITs. Therefore the user must take care to define or redefine LIMITs after using the HSCmmt macro.

Below is an example run using the FV.GF geometry file.


run maxhmmt.lib /call
read fv
dep 5
vcg 8
so we lc
un mt
report
.HSCmmt 15, 100 `%1 - initial (roll) angle, %2 - initial hmmt
print preview
report off
end