Friday, May 11, 2012

LCS - Module Swapping

ASuW Module - 30 mm Gun

The LCS was envisioned to be a flexible and rapidly adaptable seaframe carrying customizable mission modules.  In fact, depending on which reports are to be believed, the LCS's high speed was less about tactical uses and more about high transit speed to and from the module swapping location.  Unfortunately, module swapping (not that there are any!) has proven to require two to three days of continuous work which kind of negates the flexible and rapidly adaptable portion of the concept.

Related to module swapping comes this tidbit from the Department of Defense Developmental Test and Evaluation and Systems Engineering FY2011 Annual Report, March 2012, p.67.

"While the MM [mission module] swap aboard LCS 1 was completed within the threshold time period, the stability limitations and tight quarters aboard the mono-hull seaframe became evident. In order to maintain the allowable list angle during movement of the 15,000 lb Remote Multi-Mission Vehicles (RMMV), the ship’s force needed to balance the ship by emptying a JP-5 fuel tank on the port side of the ship, and by placing a weight equal to that of an MH-60S helicopter on the starboard side. Changes have reportedly been incorporated into the LM design for LCS 3 and beyond that will increase stability and should eliminate the need for adding weight to accommodate mission packages."

Note that movement of a 15,000 lb object was sufficient to cause unacceptable list angles.  The LCS displaces 3000 tons.  A 15,000 lb object is 0.25% of the total displacement.  That's a pretty insignificant object to be causing stability issues.  One has to wonder how the movement of helicopters around the flight deck will be accomplished.

Testing the Mine Countermeasures (MCM) Module
So, once again we see a vessel that has serious weight (remember, buoyancy tanks had to be added to the stern) and stability issues which further complicate an already difficult and time consuming module swap procedure.

I think we're going to see far less module swapping than envisioned in the original concept.  In fact, there are signs that the LCS is moving towards a single purpose vessel with module swaps occuring only rarely.  More on this at a later time.

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