Question:

I am calculating the stability for the crane lifting requirements in 46CFR
173.025 for a vessel on exposed waters using counterballast.
    
How do I include the factor "K" in my calculation.  The requirement is
A2 > A1 + K.  Using the residual ratio limit I can determine A2/A1, but
I haven't been able to figure out how to include "K" in my calculation.
    
Do you have any advice or an existing run file to do these calculations?



Answer:

Since 46CFR 173.025 is really wanting the residual area from "theta(c)" to
"theta(f)" to be at least "K" (A2 - A1 > K), you can use the LIMIT AREA
command:

 LIM AREA FROM 0 TO FLD > 7.0
 SOLVE
 STATUS `<-- if you want to show the condition before dropping the load
 DELETE "HOOK LOAD"
 SOLVE TRIM | STATUS `<-- shows the condition immediately after dropping load
 RA 0 2.5p /LIM `<-- change the "p" to "s" if heeled to port with load