Have a WPPlus. What shaft exactly is seized?? Everything can be replaced and Peter at WindPilot had the parts
to do repairs
on mine from physical damage. Taking them apart can be an issue with stainless fasteners in aluminum
but patience, selective use of heat, penetrating oil
and persistence usually wins out. Took me three days to get the bolts out of the rudder
coupling. Reinstall with liberal use of lanolin/Lanocote will take care of the fastener issue for future work. I'd recommend you disassemble the vane and reassemble using the above in any case.
The vane has worked great on my boat steering
downwind with 8k or so relative wind
. Did make an 8"X4' light air wind vane
out of corrugated plastic which greatly helped its light air performance. Finding a used one is a major find and hopefully a big money
saver as new ones are north of 5 boat units.