bearings for freestanding rotating mast

Would it be possible or practical for the home builder to make two simple bushings from uhmwpe ,one inset in the top and slightly proud of a carbon tubular stub mast ,the other at at deck level around the stub mast and made with a flange ,so that a tubular mast of the right diameter and made with a sort of bell housing and flange at the bottom to accommodate the deck level bearing, could be dropped down around the whole assembly? If not has anybody any sugestions as to how a homebuilder might tackle this problem?

 

I just did this (twice) on a cat ketch recently. I didn't use an internal bearing, all were external and the spars were aluminum. The partner bearing was just a doughnut with and the heel bearing was as you've described a flange. I also drilled a few slots for moisture drainage. It worked well (still does) with little friction. Don't over think it, the self lubricating properties will bail you out. I used through fasteners on the partners and #14 screws on the step bearing to the keel batten.

 

I had an even simpler arrangement for a rotating mast on a small sail, consisting of a tubular aluminum mast fitted over a steel tube with a thin sacrificial aluminum liner between. Although intended as a temporary trial for experimenting; it worked fine for a long time without lubrication, the liner was only replaced once. The bearing length was about 8% of the mast hieght.