displacement is how much the boat actually weighs; remember our good friend Archimedes (at least I think it was him) that determined a floating object displaces its own weight in water. The real question is whether the displacement weight includes mast, boom, rigging, cushions, sails, anchor/chain, etc., or is it just for the hull? You can assume it does not include the weight of an outboard or other equipment like electronics, and any water or fuel in tanks. If you are conservative and assume that none of the above are included in the 1600 lbs., you can figure the boom/mast weigh about 60 lbs, an 6 hp two stroke weighs about 50 lbs, and then give yourself another 100 lbs for the rest. Hey, that's about 1800 lbs, which is very close to the "net weight" figure you found! Cool.