Northwest Marine Trade Association (NMTA) | 1,089 followers on LinkedIn. Growing Boating in the Pacific Northwest, since 1947. | The NMTA is the country's largest regional marine association. Founded in 1947, the Association quickly expanded its vision of a unified industry by pitching a tent on the shores of Lake Union and holding its first boat show. Today, NMTA represents more than 600 companies in the recreational boating business, including boat dealers, boat brokers, marinas, boatyards, boat and boating accessory manufacturers, retailers and suppliers of boating accessories and services.