Rob,

An observation.

My mast has the internal one and it is showing signs of corrosion and pulling through the wall. Maybe this is only a reflection of age or perhaps not enough duralac when it was put on. (when I had the failure of my hook and pully last season there was no evidence of duralac around the fittings) I'm planning to replace it with the AHPC one and or do a new mast, if funds permit, as part of my winter overhauls.

Cheers