Rudder @ bow. Why?

[Twister_Ken]

Ashore @ Bertons, Lymington are a 12 meter and a 6 meter. Both have rudders a few feet back from the forefoot, as well as conventional rudders @ the back.

Anybody know why, or care to speculate?

Ken

 

[Mirelle]

Leading edge slats

I dimly recall that, if you can turn up the right edition of "Skene's Elements of Yacht Design", by Francis Kinney, you may find an explanation.

I think (I most certainly stand to be corrected!) that these devices are not really bow rudders but are intended to improve the efficiency of the keel as a foil when going to windward, just like the leading edge slats that are deployed from the wing of a civil airliner as it comes in to land.

 

[Twister_Ken]

Maybe, but a long way forward from the keel

Vaguely wondered if, with a bit of weather helm on the 'real' rudder, and a few degrees of upwind twist on the front rudder (so both are oriented the same way, rather than being arcs of a single circle), it would lift the things higher to windward.

 

[gus]

Multipurpose!

It may be a secret means of helping to steer the boat when going astern or it could be an early warning device to let you know that in another half second you are going to hear an almighty bang as you keel collides with that growler of a container.

 

[peterb]

I seem to remember that this was tried on one or more 12 metre America's Cup boat, in an attempt to get greater manoeuvrability for the pre-start manoeuvres in match racing. The idea was that a normal rudder works by pushing the stern in the wrong direction, so that the boat only starts to move in the right direction after the keel has been skewed to the water flow. A bow rudder, though, should have an immediate effect in moving the boat in the right direction. The idea didn't get generally taken up, though, so presumably it didn't work.