Man Overboard Device Saves Sailors' Lives

Story Number: NNS071109-07Release Date: 11/9/2007 8:14:00 AM
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By Mass Communication Specialist Seaman Matthew Williams, USS Harry S. Truman

USS Harry S. Truman At Sea (NNS) -- USS Harry S. Truman (CVN 75) Sailors can rely on a new safety device to help save their lives. The Man Over Board Indicator (MOBI) was installed on all of the ship's float coats Nov. 5 and 6.

The MOBI is a new three-part system that will track and help to recover a Sailor should he fall off the ship.
Andrew Malleck, an engineer from Briar Tek Inc., said the new system drastically improves the recovery time of a man overboard.

"From the time a Sailor hits the water until they are standing back on the ship is only a lapse of eight to ten minutes," Malleck said.

The MOBI is a three-part system: a transmitter on the float coat, a receiver in the pilot house and a directional finder on the rigid hull inflatable boat (RHIB).

The transmitter is a small blue square device with a long antenna running through the float coat. On newer Mark-1 float coats, the transmitter is in a pouch on the lower left side; with the antenna running up the inseam and around the neck. Older coats have the transmitter on the lower part near the belt buckle, and the antenna runs up the bladder and around the neck.

The transmitter is activated when fully submerged in salt water for three to five seconds. At that time it will transmit two serial numbers; one number is assigned to the ship and one is specifically assigned to a Sailor; telling the ship exactly who fell into the water.

Lt. Cmdr. Jeffrey Orberson, the ship's maintenance manager, said the transmitters can be manually activated should the water not trigger them.

The third part of the system is the direction finder on board the RHIBs. Unlike conventional GPS-based systems, which send a signal all the way up to a satellite, the MOBI system uses a signal broadcasted out on an AM/FM frequency air distress channel, coded to ensure that only the Navy can decipher it.

RHIBs can track and locate the Sailor's position based on the signal strength. The approximate range of the system is eight to 12 nautical miles.

The system will help prevent false man overboard drills, and help the ship to maintain operational commitments such as flight operations, Orberson said.

"These systems are designed to cut down on time trying to locate the Sailor, and ultimately save lives," Orberson said.

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