Question

While testing a loading condition for a wind and rolling Criteria GHS returned the error message "roll angle must be first". What does this mean and how do I correct it?


Answer

The problem here is that the tank loading happened to be such that she lists to port without wind. The run file didn't take this into account; it applied wind to make it heel to starboard when it should have set the wind to induce more heel on the same side of the initial list.

The proper sequence is:

1) Set the loads

2) With HMMT off, solve for equilibrium heel

3) Set the ANGLES direction accordingly (ANGLES *)

4) Turn on the heeling moment

5) Set the HMMT direction also according to the list (HMMT *)

6) Solve for equilibrium

7) Heel upwind by the roll angle (HEEL=*-ROLL)

8) RA /LIM

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