Beanboy - perhaps you refer to what I would call the rudder cap assembly?
I've done a couple of these on Epics - Currently refurbishing a V10 and replacing the rudder cap assembly - they go brittle with exposure to UV.
A relatively simple procedure - CAREFULLY remove/scrape/grind/sand away old outer from the boat clean area thoroughly (Acetone). I use 'Sika 291' adhesive/sealant to install the new cap assembly (be sure to have the cap screwed into outer for this) it will hold its roundness/shape - also take note to line it up correctly...when dry job done!
There is about 30-40min labour and about AUS$20.00 in materials - hope this helps.
Previous craft: Affinity, Endorfinn, Multisport, Epic V8, V10sport, V10, V12, Fenn Swordfish, Spirit PRS Elite; Stellar S18S, SR, SE, SEL, S2E, S2EL
Current Skis:
Huki S1-R
Stellar S18S - Excel
Stellar SR - Ultra
Skis on order: None!