Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
Re: How does a submarine bank when turning to port or starboard?
Posted by:
ROBERT M.
()
Date: January 12, 2005 02:54AM
Dan, Michael, et al:
"Submarines may experience a phenomenon during high speed turns which results in a large, undesired depth excursion - this is
"snap roll." Snap roll occurs when the submarine begins turning
and develops a transverse velocity as it "slides" through the turn (think of advance and transfer), this transverse velocity component
combines vectorially with the large forward velocity of the heeling submarine to create a lift force on the fairwater (and to a lesser
extent, bow) planes which produces an even greater heeling moment on the ship. The large heeling angle, in turn, causes the rudder to act as a diving stern plane and may result in a significant depth excursion. This effect can be mitigated by limiting the rudder angle during high speed turns, thus limiting the diving plane effect of the rudder. In adddition, the use of "X"-dihedrals may mitigate this effect."
Seat belts for the planesman and helmsman? You betcha!
Regards,
ROBERT M.
"Submarines may experience a phenomenon during high speed turns which results in a large, undesired depth excursion - this is
"snap roll." Snap roll occurs when the submarine begins turning
and develops a transverse velocity as it "slides" through the turn (think of advance and transfer), this transverse velocity component
combines vectorially with the large forward velocity of the heeling submarine to create a lift force on the fairwater (and to a lesser
extent, bow) planes which produces an even greater heeling moment on the ship. The large heeling angle, in turn, causes the rudder to act as a diving stern plane and may result in a significant depth excursion. This effect can be mitigated by limiting the rudder angle during high speed turns, thus limiting the diving plane effect of the rudder. In adddition, the use of "X"-dihedrals may mitigate this effect."
Seat belts for the planesman and helmsman? You betcha!
Regards,
ROBERT M.
