Nearly 5,000 more sailors than previously planned will be cut from the ranks in 2007, according to budget documents obtained by Navy Times.

The new cuts mean 17,927 sailors must leave the Navy over the next 18 months.

The cuts are designed to result in nearly $1 billion in manpower savings. Officials say that savings will be plowed into accounts to pay for future ships and other modernization priorities.

The news comes as the service prepared to release its proposed 2007 budget Feb. 6 as part of the president’s annual request to Congress.

“This puts us on a steeper glide slope,” said one senior defense official familiar with the Navy manpower cuts.

For sailors who might not have heard, the message is clear: The Navy continues to get smaller and could be cut further still.

Since 2003, when the Navy had an active force of 382,235, manpower cuts have occurred each year. Officials always have been cagey about projected total end strengths, saying no hard target has been established. Force cuts, officials contend, always depend on a number of factors, including crew requirements on more modern warships, size of the fleet and myriad privatization efforts.

Current plans will result in a force of 340,700 by 2007 — 4,600 lower than Navy officials projected in the 2006 budget.

What is clear is that manpower costs continue to climb, even as the service is cutting its ranks to try to stem the negative fiscal tide.

For example, even with their projected savings of $972 million factored in, the Navy’s 2007 manpower costs are still expected to be $1.4 billion higher than in 2006.

The increases include $1,161 million more for basic pay, $898 million more for housing allowance and an additional $67 million in special pays.

“Navy manpower is our single highest life-cycle cost driver,” proclaimed a 2007 budget document acquired by Navy Times.

Those costs could drive even deeper cuts, though Navy officials would not confirm official targets beyond fiscal 2007.

The Navy’s former chief of personnel, Vice Adm. Gerry Hoewing, told Navy Times last August that the service has plans for a 320,000-sailor force by 2011; at the same time, he said it was not “a hard and fast goal,” either.

The service would have to cut an additional 6,900 sailors annually over the next three years to reach that goal.

Still, manpower requirements for the next several years continue to be in flux.

The service may have to rethink its bottom-line end strength to account for recently added missions, such as riverine warfare units and expeditionary battalions, which are expected to make the service more involved on the ground in Afghanistan and Iraq.