The Bow Ramp

Saturday, March 26, 2005

LCS Part I

Over the last few years, I have commented in one place or another about where the Navy seems to be going with the concept of Littoral Combat. Essentially, the idea is that the U.S. Navy no longer has any potential enemies that could challenge it on the high seas. On the other hand, the United States may very well find itself fighting a regional war where the current mix of ships is either inadequate or overkill. The plan is to develop new ship types and tactics to better fight that sort of war in conjunction with the Navy we already have and need to maintain. One of the pieces of that strategy is the proposed Littoral Combat Ship. The rationale for LCS comes from the fact that there are never enough men or ships to do what you would like to do.

A little History

During the Cuban Missile Crisis, the Navy was tasked with interdicting Soviet ships transporting military equipment to Cuba. Even though Cuba is a small country it took a very large number of Navy ships and aircraft to effectively blockade it. All of those ships (Cruisers, Destroyers, Destroyer Escorts, Etc.) had large crews, were very expensive to operate, and were major overkill against an un-armed merchant ship. From one of the lessons-learned of that episode came the Ashville class Patrol Gunboat.
If I recall correctly, the Ashville’s were the last Navy ship type that was designed by actual Navy (as opposed to naval) architects. Since then, the Navy has relied exclusively on civilians to design their ships. The idea was to design a ship that was lightly crewed, fast, relatively cheap to operate, and reasonably armed. In addition, it would need the capacity to stay on station for several days or weeks without returning to port. That was actually a monumental task. Some of the problems they had to overcome included:
Ships of that day were very manpower intensive; there was little or no automation.
The existing power plant options (diesel and steam) each had scalability issues in a small, fast hull.
Seakeeping. Small ships/boats typically have a difficult time in heavy seas.

The final design achieved most of the goals through some definite “out of the box” thinking. These PGs incorporated a lot of “firsts” for the Navy. In order to have a sufficient loiter time, the ship had two diesel engines for economical cruising. For high-speed operations, the PGs were equipped with an LM1500 gas turbine. The diesels and turbine were coupled through reduction gears to twin shafts with variable pitch screws. The engine controls were automated and could be directly controlled from the bridge or the Enclosed Operating Space (EOS.) The EOS was another first for the Navy. In order to keep the weight down, the hull was constructed of aluminum and the superstructure was fiberglass. The weapons systems were not so innovative on most of the PGs. The standard armament was an enclosed 3”/50 Cal. Gun forward, a 40mm gun aft and twin .50 Cal. Machine guns on the bridge wings. They were equipped with a MK63 fire control system. All of those items were off-the-shelf. The original manning was a crew of 28 (four officers and 24 enlisted.) Two of the Ashville’s (USS Antelope and USS Ready) were equipped with experimental MK87 digital fire control systems. In 1971, the 40mm guns were removed from Antelope and Ready and replaced with missile launcher boxes. Two other PGs (USS Grand Rapids and USS Douglas) were also subsequently fitted with missiles, but not the digital fire control system.

There were a total of seventeen Ashville’s built. The first one was commissioned in 1966 and the last one decommissioned in 1977. The class did have some problems. The original diesel engines were poorly designed and failed frequently. The Navy sued the manufacturer and eventually won; forcing the manufacturer to upgrade the engines twice. The stainless steel screws were prone to severe pitting from cavitation at high speeds. Follow on PGs were built with monel screws that did not have the problem, but the older ones were never back fitted. The original surface search radars failed regularly and were also subsequently replaced. Being experimental, the digital fire control systems on Antelope and Ready were frequently out of commission for the first few years. The Ashville’s served in Vietnam both on coastal patrol and up some of the larger rivers—coming under fire on numerous occasions. Later, some of them were home ported in the Mediterranean Sea.

When they were designed, it was still the “Old Navy” and crew comfort was not much of a consideration. They were cramped and rough riders. Being aboard one during a storm was no picnic. The crew could get pretty worn-out after a couple of weeks at sea.

It was the best duty I ever had in 23 years in the Navy.

By 1975, they were all gone. The Navy was shrinking, the manpower was needed elsewhere and the habitability issues did them in. But they left a legacy. All of the subsequent surface combatants were powered with gas turbines. They were all equipped with digital fire control radars and missiles.