The Coast Guard is struggling to meet its homeland security missions in addition to its traditional missions, according to a new report from Homeland Security Inspector General Richard Skinner.

“The Coast Guard continues to experience difficulty in meeting its homeland security performance goals,” the report states.

The Coast Guard did not meet performance goals for two of its homeland security missions in fiscal 2006, the most recent year studied. The unmet goals were defense readiness, which it failed to meet for the sixth year in a row, and interdiction of illegal migrants, which it failed to meet in four of the six years surveyed, the report states.

The Coast Guard blamed the shortcomings on its aging cutter fleet, which sometimes made too few boats available for use. In the case of defense readiness, it also blamed limited time for training.

Setbacks related to the Coast Guard’s $24 billion Deepwater asset modernization program, which has encountered delays, cost increases and rejection of new assets because of structural problems, have contributed to the difficulties in maintaining a ready fleet, the inspector general said.

The Coast Guard is continuing to face difficulties in Deepwater, including problems with the Fast Response Cutters, the report states. The report also notes that the Rescue 21 program “ has been “plagued by delays, technical problems, cost escalation and a delay in full implementation, which has slipped by five years.”

Among its traditional missions, the Coast Guard failed to meet its performance measure for marine safety. It came very close to — but technically did not achieve — performance benchmarks for search and rescue, protecting marine resources, and aids to navigation. The inspector general said those were mostly technicalities, and the benchmarks themselves were imperfect.

The Coast Guard’s Deepwater and Rescue 21 programs have been among the largest contracting programs in the Homeland Security Department. The programs include not only ship construction but also acquisition of and integration electronics and computer equipment and software.