Surviving the High Seas: A Challenge for New Navy Vessels?

Posted by PortVision

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A change made in the weight and design of the US Navy's new high-speed transport vessels has required millions of dollars in repairs. The weak bows of the Expeditionary Fast Transports (formerly called Joint High Speed Vessels) occurred as a result of a decision by the Navy to save weight when the vessels were under construction. As reported in January by Bloomberg, Senate Armed Services Committee Chair John McCain expressed concern since multiple vessels of the class have had damage to their bows.Waves in heavy weather hitting the bow superstructure did the damage. The primary mission of the ships are transport in coastal waters which are usually milder than the rougher seas that might be encountered in the open sea. Current operating restrictions require vessels to avoid or divert course from high seas, and to travel at speeds much lower than their maximum specifications.

As described by the Navy, the ships, built by Austal Ltd. are twin hulled all-aluminum catamarans built to transport 600 short tons of military cargo, 312 troops and a crew of 22 intra-theater in sea state 3. They have a range of 1,200 nautical miles with an average speed of 35 knots. The vessels bridge the gap between low-speed sealift and high-speed airlift. Their shallow draft allows operation in most ports and waterways and facilitates interface with ro/ro discharge facilities. They include a flight deck for helicopter operations. Propulsion is by water jet. They displace 2500 metric tons (26460 long tons).

Ten of the shallow-draft vessels were purchased for $217 million each. They were built at Austal's Mobile, AL shipyard. Five were delivered in 2015 and are being utilized. At this point, the Navy has spent almost $2.4 million to strengthen the bows of four vessels. These retrofits added 1,736 pounds to the weight of the vessels affecting the ship's range when loaded only minimally.

In addition to the bow strength problems, the generators aboard these vessels have been plagued by poor reliability. These were supplied by Fincantieri SpA. Bloomberg reports that the generators failed at rates higher than expected.

A full report on these vessels was expected to be released on February 1 by the Military Sealift Command. At this writing nothing has yet been posted to the website regarding these failures.

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Posted on Apr 12, 2016 6:07:00 AM

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