Martin P5M Marlin. The Martin P5M Marlin (P-5 Marlin after 1962), built by the Glenn L. Martin Company of Middle River, Maryland, was a twin piston-engined flying boat that entered service in 1951, and served into the late 1960s with the United States Navy performing naval patrols. It also served with the United States Coast Guard and the French Navy. 285 were produced.