Marked Up

By Dan Dupont / April 25, 2012 at 4:26 PM

In the House Armed Services seapower and projection forces subcommittee's mark of the FY-13 defense budget, released today, panel members raise the issue of cracks in Navy ships -- and cite our own Inside the Navy for its reporting on the issue:

Items of Special Interest

Shipbuilding material comparison

In a recent article published in "Inside the Navy", it was reported that, “superstructure cracking in several classes of surface combatants is being addressed, but in some cases is proving costly”. The committee is aware that three materials have been used in the deckhouses of surface combatants: steel, aluminum, and most recently for the deckhouse of the DDG-1000 Zumwalt class, composite material.

The committee is also aware that there is a cost differential in both up-front procurement and production and in lifecycle maintenance cost for these materials.

The next opportunity that the Navy will have to influence a design will be with Flight III of the DDG-51 Arleigh Burke destroyers. The committee directs the Secretary of the Navy to provide a report to the congressional defense committees with delivery of the fiscal year 2014 budget request, comparing the estimated construction costs for a deckhouse made of each of the three materials, or even a possible hybrid of two or all three, and then compares the estimated lifecycle costs for the designed life of the ship.

Here's the top of the story the subcommittee is citing, published in the April 16 issue:

Naval Sea Systems Command is telling Congress that superstructure cracking in several classes of surface combatants is being addressed, but is in some cases proving costly.

Cracking problems on the CG-47 Ticonderoga-class cruisers "appears to be the most pervasive as it extends to all ships of the class," according to the March 5 document, "Report to Congress: Surface Combatant Topside Superstructure Cracking," which was recently reviewed by Inside the Navy.

In addition to facing fatigue cracks, "stress corrosion cracking is also pervasive and affects widespread areas of the superstructure." Four of the last five ships in the class also saw higher sensitization -- a process that changes the aluminum and makes it more susceptible to corrosion -- in a shorter period of time.

"Costly repairs resulting in extended maintenance availabilities have been executed or are planned, subject to availability of funding," the report continues, noting that a CG-47 Superstructure Cracking Task Force has developed a repair plan that requires $4 million in spending from the Navy's research and development budget and another $270 million from the operations and maintenance budget to fix cracks and develop mitigation techniques and tools. Of that amount, $152 million would be spent between fiscal years 2013 and 2017.