I would not recommend putting holes in the rudder post tube below deck. You'd need to add a lip-seal if you did this, which would likely require some fabrication, and also make sure the tube is still well supported. Plus, there is no quadrant, so you'd have to figure out how to attack the feedback sensor to the rudder post in an easily removable way.

If your autopilot drive is mounted above deck, you may be able to mount the rudder senser directly to the drive ram. B&G autopilots sell a rudder sensor intended to be mounted on the ram--perhaps Raymarine does as well...

--brendan

:: I am installing a Raymarine rotary rudder position
:: reference sensor on TAZ!!. Has anyone done this? Do I
:: dare open up (high up) the rudder post housing below
:: decks?