IN EARLY 1943, Allied maritime supply lines faced a new threat. The hulls of several Liberty ships and tankers (Liberty design variants) catastrophically split in two without warning while underway. Other ships developed serious cracks. Department of the Navy and Admiralty research teams worked to determine and eliminate the cause before seaworthiness of these vital merchant ships resulted in operational and merchant mariner recruiting issues.

The United States Navy conducted its first full-scale, land based test of a surface ship propulsion system at a manufacturer's facility in 1937. Since 1941, the United States Navy has evaluated full-scale, surface ship propulsion systems at its own facility. That facility, originally known as the Fuel Oil Testing Plant, had several name changes over its 115 year history. Known as the Naval Ship Systems Engineering Station (NAVSSES) from 1979 until 2015, on 1 October 2015, the command was re-aligned to create an independent command within the Naval Surface Warfare Center and was renamed the Naval Surface Warfare Center, Philadelphia Division (NSWCPD). During the intervening 74 years since it began full-scale, surface ship propulsion systems testing, NSWCPD has evaluated 12 surface ship propulsion systems; six systems for new ship classes, five experimental systems, and one system for a foreign military vessel. While previous papers have addressed an individual test, or a specific test site, this paper uses all 12 full-scale surface ship propulsion system tests to assess the value of land based to the Navy. Full-scale, land based testing provides significant advantages in demonstrating readiness for transition to acquisition, in the reduction of acquisition program risk, and in improving engineerig support during service life. The approach of the United States Navy to full-scale, land based testing is compared to that taken by the Royal Navy. Land based testing versus installation in a test ship is also discussed. This paper was presented at the American Society of Naval Engineers Intelligent Ships Symposium, 15 May 2013.