Groton — The Naval Submarine Base is closing today at noon to all but essential personnel and the base commander says Hurricane Sandy preparations are finished.

Capt. Marc W. Denno said the base is closing primarily due to the governor's decision to close state highways and bridges at 1 p.m. He said his biggest concerns are flooding on the lower base because of the storm surge and the possibility of a significant power outage in the community.

The five submarines in port were not sent out to sea in advance of the storm, Denno added. But the lines tying the submarines to the piers were doubled and hatches were closed.

The emergency operations center at the base is partially manned now, Denno said, and either Denno or the base's executive officer will be there as the storm progresses.

Denno said 1 foot of water could go over the top of the quay walls on the lower base at about 10 p.m., causing minor flooding.

"We put over 8,000 sandbags in place and in the long run, it will have no impact on the base," he said today.

The base has a generator, he added.

Denno said he expects to reopen the base Tuesday but he said that decision will depend on the severity of the storm damage in the community, since it would be difficult for base personnel to get to work if trees are down, power is out and roads are still closed.

Less than 1,000 people are considered essential personnel and will remain at work on the base today. Sailors who are not essential personnel will be in liberty status and civilian personnel will be on administrative leave.

Several submariners from the Groton-based USS Mississippi sailed aboard the square-rigged sailing ship HMS Bounty for two hours in Long Island Sound on Thursday. After leaving the region, the crew of the Bounty was caught in Hurricane Sandy off the North Carolina Outer Banks and forced to abandon the tall ship. The Coast Guard is searching for two of the crew members.

"We just hope for the best of the crew," Denno said. "We hope everybody returns safely."

j.mcdermott@theday.com