WesWorld

Quoted

You will sim your sub in awash condition, just
about to go under. Specify depth as about 2/3 of
beam; this seems typical for subs of pre-nuke era.
Provide "miscelleneous weight" of about 1/4 to 1/6
of normal displacement - this is your ballast tank.
(Some nations' real subs had closer to 1/3, but
this will not sim well.)

For freeboard, enter zero. (To avoid computer
error, the program will adjust this to 0.1 ft
(0.03 metre). You'll get a "horribly cramped"
warning - ignore it. However, if your sub has
stability less than 1.0, you'll have to redesign
it. Always enter steadiness of 50 pct. (If you cheat
to get more stability, whoever re-runs the sim will
catch you!)

Multiply composite hull strength times 100 to
get operational diving depth in feet. (Multiply by
30 for depth in metres.) Emergency diving depth
is 1.6 times operational depth; crush depth is 2.5
times operational depth.

You will find that the smaller the ballast
tank, the deeper your sub can dive. However, the
ballast tank is your reserve bouyancy, and will
determine how much depth-charging you can take
and still make it back up!

Adjust your report file. Just delete all those
warnings about lack of seaworthiness - a dived sub
obviously isn't seaworthy by surface-ship standards.
Specify crew as about half the listed minimum.
Don't forget to list operational diving depth.