R Speculation

Can someone explain why an old National 12 thing would want something as sophisticated as that tilting rudder, and what on earth do they expect to achieve with it, are they a bit nosey?

Ah, but why does it need to tilt? I can understand the addition of a t foil to increase stability, but you couldn't possibly adjust that in any way that is going to do anything other than increase drag surely. All it's going to do is work like a trim tab to adjust fore and aft pitch and the moment you pitch it down to keep the nose down, it'll increase drag, quite dramatically.

Or is that the idea, they pitch nose down into the gybe?

Tfoil can a) improve pitch stability and b) improve performance from suprisingly low speeds due to a number of phenomena:
1) reducing displacement of vessel - the foil, if high aspect, is more efficient at carrying load than a hull above, say 5 kts, so it makes sense to load it up
2) if near the surface it can destructively interfere with the stern wave, flattening it down and reducing wave drag
3) on a short, rockered boat, the foil operates in a way similar to  a spoiler on a 911 or some such, that the total force vector from the foil (i.e. including drag) acts in the direction of motion - i.e. even the drag works for you.

I would be very surprised if the RS has a tfoil system, as, if done well it will add about a grand to the cost, and if designing from scratch you'd have a lot less cost adding a foot or so of length to get the same performance hike.

Originally posted by jeffers [QUOTE=iGRF]..... they also said that they would not gybe a N12 in anything above a F4 without a t-foil rudder as the chances of a swim were around 80-90%.... This is a from someone who is a very handy sailor too.

A pre-t-foil N12 at our club seems entirely capable of gybing in any weather I'd care to be out in.
Unless we are talking about a design of 12 that is reliant on the t foil, I don''t think your statement stands up.
It may be the case that if you optimise a hull for use with a t foil, it isn't very good without it.

Originally posted by iGRF In other words it's making up for the design shortfalls of the hull, nothing should be 12 ft anyway, stupid length, 14 ft is the minimum length anything should be to go to sea in.