The Cape Dory Board

I have the rig-rite bronze outboard mount. It appears that a long shaft yamaha 4hp will just barely be below the surface. What length shaft is good for this type of mount

Thanks

I am trying to locate the the mast and boom bales for a boom vang. I have the old Sparten catalog numbers, but they appear to be no longer available. Rig Rite has a slot and eye flush mount bale for the boom that uses a wire with a ball attached, but I cannot seem to find a bale for the mast. I did ...