Buy it
If the owner thinks it is a rowboat offer him 50 bucks for it, then make a mast and boom, get some dacron for a sail. Make a centerboard and a rudder in your workshop, they are easy to make. For about 200 bucks you can have a nice sailboat. Making a mast and boom is easy. I was amazed how easy. Start with three eaqual length boards that are knot free. Mix some epoxy and fibers to make a paste. Should be like peanut butter or mayo. Coat two boards on one side and the other on both sides, alternate the grains in the boards and make a sandwich out of the three boards. Use c-clamps or bar clamps or both and clamp all along the length. Let cure. Hint, use saran wrap under the clamps and pieces of wood to spread the load over a greater area. Now you have a long square piece of really strong wood. How do you make it round? Using a block plane plane each corner to make it eight equal sided. This only takes a few minutes. Sweep up your shavings!! Now plane each corner to make it 16 sided. Amazing it is almost round, sweep up your shavings!! Now plane each corner to make it 32 sided, it is now round. Take a belt from a belt sander and pretend you are shining shoes and sand any remaining sharp corners. You now have a nice long round strong mast. Coat with epoxy, or paint, or varnish or whatever.