Complex sentence: In 1937, the company built the Western Flyer as a purse seiner, and in 1940, this boat was the vehicle that carried John Steinbeck on the journey which he documented in The Log from the Sea of Cortez.
Split into simpler sentences: In 1937, the company built the Western Flyer as a purse seiner. In 1940, this boat was the vehicle that carried John Steinbeck on the journey which he documented in The Log from the Sea of Cortez.