Welcome to Irwin Marine - New Hampshire's leader in new and used boats sales. An authorized dealer for Sea Ray, Princecraft, Alumacraft, Berkshire Pontoon boats, Sea Doo, Ski Doo and Old Town Canoes and Kayaks. Established in 1919 we are a full service marina offering boat slips, valet, storage, service and parts. With three locations to serve you in Laconia, Alton and Hudson, NH.