A $17.8 billion submarine contract, the biggest weapons deal announced by the U.S. military in more than a dozen years, kept Pentagon awards from sinking last month.

The contract to General Dynamics Corp. (GD:US) and partner Huntington Ingalls Industries Inc. (HII:US) had been stuck in limbo during Congress’s budget squabbles last year. It was freed up when the president signed a $1.1 trillion spending bill in January, letting the Defense Department begin funding new projects again.

April’s awards rose 84 percent to $35 billion from $19 billion a year earlier, according to data compiled by Bloomberg. Contracting specialists said the boost was an anomaly rather than an indication that military spending is rebounding.

“This is more of a one-shot deal,” said Mark Amtower, a partner at Amtower & Co., a Clarksville, Maryland-based consulting firm specializing in government contracting.

The five-year agreement for 10 Virginia-class submarines, announced April 28, is the Navy’s biggest-ever shipbuilding contract, according to Rear Admiral David Johnson, program executive officer for submarines.