      Top arrow   

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