LIMIT commands for a variable area criterion.Question:Given the following criteria how would I write a limit command to satisfy the equation ?

An area under each righting arm curve up to the angle of maximumrighting arm of not less than the area determined by the followingequation:A = 10.3 + 0.187 (30-Y) at max RA.

Answer:

It takes two consecutive LIMIT commands to handle this criterion:LIMIT(1) AREA FROM 0 TO MAX AT 15 > 13.1LIMIT(2) AREA FROM 0 TO MAX AT 30 > 10.3These are mentioned in the manual under the LIMIT command in the Command Dictionary.Syntax Notes:1) These two limits must be consecutive; e.g. 1 & 2 as above. 2) The /LIMIT:COMBINE subparameter must also be used on any RA command where the two limits are to be evaluated as a single varying limit. The interpretation is that the limit value is 13.1 when the angle of MAX is at 15°, 10.3 when it is at 30° and a linear interpolation between 13.1 and 10.3 when it is between these angles. Keywords: Offshore Supply Vessel Criterion, IMO A.469 2.5.2

Copyright (C) 2011 Creative Systems, Inc.