      Bottom arrow   

     The  bottom arrow sets the sub moving upward.  Think of 
employing a game joystick  or an airplane joystick that is 
centered at  the middle of the four direction arrows. Pulling 
back pulls the nose of the sub up for an ascent, while pushing 
forward pushes the nose down for a descent. Each key press 
accelerates the motion which is depicted in the attitude 
indicator. The horizon line will move below center to represent 
the sub nose taking an upward attitude. CHASE the indicator to 
reverse the attitude change: I.E. push the top arrow to force the 
nose downward toward the horizon line. Clicking the left mouse 
button on the attitude instrument will set all attitude controls 
to neutral.
