It will sail fine without it, but it will have about 1/2" deep water in the rear near the drain. I use the plug when I push it off the trailer because the angle scoops water. I bought a quick release plug at Bass Pro, but the the plumbing department of any hardware store will have the screw in test plugs. Some cheap wines now have rubber corks that might work in a pinch. (You may NOT sniff the cork, if your biggest boat is under 27 feet though).