Wikipedia
Shannon-One-Design
The Shannon-One-Design sailing dinghy is a small sailing boat raced on the River Shannon and Loughs Ree and Derg in Ireland. The boats are 18 feet (5.49m) long by 4 feet 10.5 inches (1.5m) beam, drawing 4 feet (1.23m) with her centreboard down. They have a sail area of 140 square feet (15.6m2) set in a single sail, giving the boat what is called a gunter rig.