GHS FAQ

About LIMIT with three terminating angles

Question QA041 :
What limit commands would best address the following criterion:
At least 15 foot-degrees of area to the smallest of the following angles.
i) Angle of maximum righting arm
ii) Angle of downflooding or
iii) 40 degrees

Answer :
LIMIT (1) AREA FROM 0 TO MAX OR FLD > 15
LIMIT (2) AREA FROM 0 TO MAX OR ABS 40 > 15
This is preferable to the following:
LIMIT (1) AREA FROM 0 TO MAX > 15
LIMIT (2) AREA FROM 0 TO FLD > 15
LIMIT (3) AREA FROM 0 TO ABS 40 > 15
The reason for this is that it is possible for the FLD angle and/or 40 degrees to be later than the second intercept. Of course the area to MAX would be the critical one in this case, but since the area starts to decrease after the second intercept it is possible that the area from 0 to FLD, for example, would be less than from 0 to MAX. By including MAX for each limit, you avoid this possibility.
Note that "0" in the above limit commands is relative to the initial angle which you can set with the HEEL command or SOLVE command before doing the RA command. If you want to always begin the areas at equilibrium, substitute "EQU" for "0". If you always want to begin the areas at absolute 0 (upright), substitute "ABS 0".

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