Conversion full crew racing yacht to double-handed

[Night Sky Yachts]

I also don't think that a rudder tube is critical for a deck construction, but we asked about this the boat designer and he doesn't like it. So, we are planning to make modifications similar to the original structure as we can. Very important for racing yachts is low weight so solution presented by @gonzo is perfect.
For installing the autopilot actuator we don't need anything more than a simple aluminium (or composite) bracket fixed to near bulkhead (450 mm from rudder) and to the deck.