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SURFACE WARFARE FALL 2020
Assault Craft Unit FIVE's on-site LCAC Weld School Story by Expeditionary Strike Group THREE Public Affairs Photo by Mass Communication Specialist 3rd Class Justin Whitley
CAMP PENDLETON, Calif. (NNS) -- In a predominantly steel trade, Hull Maintenance Technicians (HT) assigned to Assault Craft Unit FIVE (ACU-5) are in for quite a surprise when faced with the challenge of welding on the Landing Craft Air Cushion (LCAC) all-aluminum hull. Fortunately, ACU-5 is home to a specialized seven-week weld school centered on the unique intricacies of aluminum welding that prepares these Sailors for such a challenge. “Aluminum differs from steel in many ways even though the basic principles are the same,” said Mr. Kirt Martin, ACU-5 weld school instructor. “Thermal expansion of aluminum is approximately twice that of steel. Hot cracking – as we call it – can occur as the weld solidifies with aluminum if not done carefully,” Martin adds. Martin, a contractor with MS Corp and professional welder of 27 years continues: “The Gas Tungsten Arc Welding process used for aluminum takes a little more dexterity than other welding processes and requires a bit of a faster pace.” With the LCAC capable of speeds of 50 knots the ‘Swift Intruders’ of ACU-5 are no strangers to a fast pace. Precisely placing the 110-ton hovercraft gently inside the belly of amphibious assault ship underway at 12 knots with a 60-ton payload on deck takes lots of skill and a little bit of luck. Sometimes rough seas result in minor fender benders while attempting this
highly technical aspect of the mission. In the war of LCAC aluminum versus ship’s steel, steel wins every time. This is where ACU-5s HTs come in. With six courses taught on-site and a throughput of 36 students each year, there is no shortage of LCAC metal experts ready to answer that call. After 12 hours of classroom lectures and 67 hours of arc-time per student, LCAC hull maintenance teams come together and demonstrate the skills they learned in ACU-5s weld course, ultimately returning almost any hull component onboard the landing craft to like new condition in accordance with Military Standard 248 and the LCAC Welding and Inspection manual. The training drastically enhances occupational standards for HTs and takes a methodical approach to specialized training, negating a ‘learn as you go’ approach, which many other on-the-job training scenarios have to offer. “Our weld school teaches the student how to weld on aluminum and stainless steel, which is specific to the LCAC community. The students get a lot of one-on-
