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". |