Ty,

I should have mentioned......on our S7 we have a ground adjustable warp drive prop and there is a 1/4" squash plate on top of the bulkhead. That may make a difference as Geowitz mentioned. I don't think the fender washers alone on top of the fiberglass bulkhead would be adequate. So our propshaft stack includes: Spacer, prop hub, bulkhead, squash plate, fender washers, AN washers, Bolts - this assembly has been stable.

Dave S