Funding for the US Navy's next-generation littoral combat ship (LCS) in 2016 needs to be delayed until their survivability and lethality capabilities are proven, the US Government Accountability Office (GAO) has recommended.
The GAO report said that the lethality and survivability of the LCS are yet to be proven, six years after the delivery of the lead ships.
The LCS is the first of a new family of surface ships for the navy.
LCS has been designed with reduced requirements compared to other surface combatants, making it less survivable in threat environments and less lethal than initially planned.
The US Navy is trying to cover-up the shortcomings by redefining the missions of the LCS.
In 2014, the navy carried out its first operational test of an early increment of the surface warfare mission package on a Freedom variant LCS, which showed that the ship reached an interim lethality requirement.
The test report of the navy declared that the ship did not meet some key requirements.
The navy does not intend to test the ship's capabilities until 2018, GAO observed.
The navy has identified some problems in the hull of the Independence variant of the ship, and intends to conduct tests in these areas. However, it has no plans to test how the variant would react in an underwater explosion.
LCS is a $34bn Navy programme for two different ships, with interchangeable mission packages.
GAO has undertaken the probe after the secretary of defense directed the navy to assess design alternatives for a possible LCS replacement, in February 2014.
LCS is designed to operate in the littoral (coastal waters) to counter growing potential asymmetric threats of coastal mines, quiet diesel submarines and detect boats that have the potential to carry explosives and terrorists.
The newest Freedom-class littoral combat ship, the USS Milwaukee (LCS 5), broke down at sea in Virginia in December.
Image: Trimaran hull of an Independence class LCS. Photo: courtesy of U.S. Navy Photo.