Complex sentence: He was superintending engineer for the Southern Pacific Company, and the Pacific Mail Steamship Company, superintendent for the Cromwell Steam Ship Company, and in his private practice as a marine engineer and naval architect he designed and prepared specifications for many yachts and commercial vessels.
Split into simpler sentences: He was superintending engineer for the Southern Pacific Company, and the Pacific Mail Steamship Company, superintendent for the Cromwell Steam Ship Company. In his private practice as a marine engineer and naval architect he designed and prepared specifications for many yachts and commercial vessels.