Replacing the mast step
Years ago when I lost my mast on my O'Day 222, I had the rigger install a new Stainless Steel hinge Tabernacle to my mast and I installed the lower part of the Tabernacle and utility plate that goes under it, myself. All I needed from the rigger was the height measurements for this plate, and I was able to make up that difference by mounting the Tabernacle and plate on a piece of Teak. To clarify; The OD 222s mast were made by Z-Spar, and the chintzy cast Aluminum Tabernacle had a built in sheave at the bottom for the the Jib Halyard, and I wanted to get rid of it. My mast has internal halyards. With that said; You may be better off going to a Dyer hinged Tabernacle, and install the lower half on your cabin top. All you need to do is mark the center of the old mast Tabernacle, take some measurements and install it. There's only four bolts that hold it on. Use a good grade of caulking on it. A rigger will probably have to remove the old cast extrusion and mount the top half into your mast, with an Aluminum fitting in your mast, but you'll probably have to ask him what kind of height will be needed for the lower half, so that your stays will fit. Unless you want to replace your stays, then you won't have to worry about it. He'll make the stays the right length.