MOBI is Revolutionizing Ship Safety

Story Number: NNS020813-20Release Date: 8/13/2002 5:58:00 PM
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By Journalist 2nd Class Ryan Hicks, USS Abraham Lincoln Public Affairs

SAN DIEGO (NNS) -- During its deployment, USS Abraham Lincoln (CVN 72) will be part of the evaluation process that will change the way the Navy handles man overboard situations.

A new three-piece system is now in place to take the guesswork out of knowing if a Sailor is possibly in the water.

A transmitter the size of a Rubik's Cube, a receiver consisting of a whip antenna connected to a small box the size of an answering machine, and a direction finder that points out the relative bearing of the transmitter make up the new man overboard indicator (MOBI) system. With MOBI, the Navy is in the process of revolutionizing safety standards aboard ships.

"The system will highly increase the probability of discovering Sailors overboard and then quickly finding them," said William Dull, a representative from Briar Tek, the company that won the bid to produce MOBI for the Navy two years ago.

This system will be the first to use active technology for the man overboard situation, rather than the normal passive mode of manual detection through the exclusive use of lookouts, according to Chuck Collins, the director of operations for the company.

Three hundred of these transmitters have been passed out so far on board Abe, with an additional 1,200 distributed among the rest of the battle group. Sailors will wear the transmitters in the dye-marker pouches in their float coats.

During the deployment, the system will be evaluated to determine possible improvements before it goes Navywide. Currently, the George Washington and Abraham Lincoln battle groups are the only ones to use MOBI, but the Navy plans to have it in place fleet wide sometime in 2003, said Collins.

The eventual price tag throughout the Navy rounds out to about $250 per Sailor.

"That's not bad when you consider that every float coat costs $350," said Collins.

If Sailor falls overboard, the transmitter will activate upon contact with salt water. An antenna located on the O-10 level will receive the signal, which is then displayed on a receiver on the bridge. The signal can be detected up to 18 nautical miles away.

An alarm will sound near the Boatswain's Mate of the Watch station, and the serial number of the transmitter in the water will be displayed on the screen. The receiver also displays the number of transmitters in the water in the event there is more than one Sailor overboard.

After the signal is received, an antenna on the tower picks up the direction of the signal and displays it on the direction finder in front of the Captain's chair. MOBI also comes with a separate portable direction finder that can be attached to the rigid-hull inflatable boat (RHIB) to help speed up the recovery when the RHIB is deployed.

Boatswain's Mate 2nd Class Ken Crowther, who stands the Boatswain's Mate of the Watch on board, said the addition of MOBI is definitely a good thing. He also added that it should not change the focus or function of the lookouts, though, because in the event of failure, there still need to be eyes looking into the water at all times.

Lt. Tom Baker, an officer of the deck (OOD) on board, was very positive about the effect the MOBI will have on the bridge watch. "It's definitely a great advance in technology toward a safer working environment," said Baker.

"And it will make life a lot easier up on the bridge, because the system tells the direction of the man overboard, and that will help the OOD make the decision what kind of turn the ship needs to make for the recovery," he continued.

And if anyone is worried that the system is expensive or difficult to maintain - once a year, pop open the transmitter's back with a Phillips-head screwdriver and change the 9-volt battery inside.

For more news about USS Abraham Lincoln, visit their custom Navy NewsStand page at

USS Stennis - aft lookout
Official U.S. Navy file photo of a lookout. New technology being adopted by the Navy improves the process of locating a Sailor who has fallen overboard.
March 13, 2002
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