Fishtail or Schilling rudder

[colinstone]

Hi,

I am building a 72foot steel replica 1920s dutch barge in NL and want to fit a rudder that is either known as fishtail or schilling. The reason it is called fishtail is that is horizontal profile looks like the vertical profile of a fish. The advantage is that it is operated through a 140 degree range ie 70 - 0 - 70. In the normal 35-0-35 range it operates as a normal rudder, but when hard over gives sideways thrust. That with a bow truster means that the barge can be moved bodily sideways.

Anyway, anyone out there got some formulae - size of rudder, balance ratio etc etc. Distance trailing edge of prop to leading edge of rudder etc etc.

To see the type of vessel see here - this is a 15m version being built at the same yard. http://www.euroshipservices.nl/stand...sp?PakketID=57

TVMIA.

[Dutch Peter]

Colinstone,

To my knowledge the range upto 70 degrees is combined with a large rudder area to be able to give a thruster-like effect. The fishtail profile is for better performance in the 35-0-35 range.

Regards,

[Danger Mouse]

www.becker-marine-systems.com

These guys produce the original Schilling rudder. Check out the site or drop them an e-mail

[Dutch Peter]

Danger Mouse,

The becker system rudder is not the same as a fishtail rudder. With the fishtail rudder the horizontal profile looks like a fish, but nothing moving.

[Danger Mouse]

Thought this was a fishtail profile without moving parts. Maybe my link should have been more specific:

http://www.becker-marine-systems.com..._schilling.pdf

[Dutch Peter]

Sorry Danger,

I didn't look any further, you're right.