O'Day 20 Boom Vang was optional most if not all years. The page below is the DS Boom Vang, but the one for the 20 was really the same. Outhaul was standard all years, but as Brian pointed out, it was just a line running from the clew of the sail through an eye at the boom end and forward to a cleat on the side of the boom, Block Action outhaul was optional (see pic below). The 20 had a sliding gooseneck so would have had a standard Downhaul to pull mast end of boom vertically down along mast slot, tied to a cleat on trailing edge of mast about 12" or so below boom. I have posted pics are from the 22 Manual, but truthfully, O'DAY used the same diagrams for most models, just changed slightly to match the specific model.