Question:

Can you provide instructions on how the margin command works in PM?

1) How does one see where the deck marking is?  Is it drawn on the display?  Is
there a place in a file to look at?


2) How the margin line information flows into GHS?

3) Is the margin line used to calculate downflooding?  Within the LIMIT
routine, is FLD the heel angle when the margin line is immersed?
How can one see where the margin line is in the output?


Answer:

1) It marks the deck edge of the component by attaching a special "DK" symbol
to the deck-edge points in the Geometry File.  You can observe this in DISPLAY
as a brown line connecting these points.  The margin values (at fwd, mid and
aft end of the component) are stored in the GF at the end of the component
record.

2) There is no "margin line" as such in GHS.  Rather the margin distances are
deducted from freeboard to deck edge (measured perpendicular to waterplane).

3) In the GHS main program you can observe freeboards with the STATUS command
using the FREEBOARD category.  It shows the minimum distance from waterplane
to the deck edge both "raw" and with the margin value deducted.  The RA
command report shows the event of deck edge immersion independently from flood
point immersion.  In the LIMIT command there are two keywords referring to the
heel angles at which these events occur: DI (deck immersion) and FLD (flood
point immersion).