The attached file shows a concept design for a T foil rudder with tilt in the stock.
It should be easy to retrofit to an existing boat and relatively easy to DIY build.
Comments welcome.
Nev
My first immediate thought's are that the pivot pin looks awfully small (although as it is just a concept, I guess you would beef that up)
As drawn the gudgeons attached to the stock look a bit thin as well.
As drawn the pin (about which the foil rotates) is 8mm dia and the pintle pivot on the stock formed from 6mm thick aluminium plate and welded to the stock. As you say it is a concept and all of the dimensions can be adjusted.
My main concern is that the blade area moves relative to the pintle as the foil angle is adjusted, and that is not the case with the more conventional arrangement of tilting the pintle and the blade together. Hope that makes sense.
There is bound to be an effect on the weight/feel of the rudder as the foil angle is adjusted. As the foil angle moves in the positive direction the blade area moves forward relative to the pintle. That will probably make the rudder feel lighter and vica versa. This aspect may or may not be acceptable. Someone may already have tried this approach and will know if it is workable or not.
Nev
Revised attachment.
Pivot pin diameter increased to 10mm, pivot on the stock increased to 10mm thickness and the profile of the rudder blade changed.