From my experience as ground crew in the last "open" Worrell (hmm- there was a "yellow boat" in that one!!) the only Mystere in that race ended up fracturing every rudder casting on the East Coast they could get there hands on!! Clearly a design flaw! I would "retrofit/upgrade" to some proven rudderheads/systems ala the old NACRA design or some of the Hobie designs IMO- parts if needed will then be plentiful/easy/cheap to come by and they will be anodized from those companies-

Kirt