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SSC-Natick Press Release

U.S. Army Soldier Systems Center-Natick
Public Affairs Office
Kansas Street
Natick, MA 01760-5012

Contact: Jerry Whitaker -- Chief, Public Affairs Office
(508) 233-5340

Date: December 2, 2004
No: 04-47

Navy life preservers improve chances of speedy recovery

NATICK, Mass. -- Accidentally blown off the flight deck of an aircraft carrier and plummeting 60 feet into the ocean, it's reassuring to know your life preserver can automatically go to work to keep you afloat and hasten your recovery.

A water-activated Man Overboard Indicator (MOBI) and strobe light are the latest life-saving features designed into two kinds of Navy life preservers through a program led by the U.S. Navy Clothing and Textile Research Facility (NCTRF) located at the U.S. Army Soldier Systems Center here.

In 2000, the Navy Sea Systems Command requested NCTRF consolidate an array of life preservers into three improved vests, said Richard Wojtaszek, a textile technologist and project officer for protective clothing.

Instead of the traditional method of developing military specifications and tasking a company to design and manufacture a product to meet the specifications, Wojtaszek worked directly with life preserver manufacturers to modify their Coast Guard-approved products to meet the Navy's needs.

"The goal in this was to try to design vests that meet UL (Underwriters Laboratory) standards," Wojtaszek said. "They were never tested before to meet current commercial standards. (Companies) are guaranteeing it's UL-approved, and that's what we requested."

He added that the process enables the Navy to easily change and improve an existing product, such as adding or re-designing a pocket to accommodate a MOBI or strobe light.

The Navy has narrowed their family of life preservers to the Mark I vest, Inherently Buoyant vest and Abandon Ship waist pack, which are available for purchase through the Defense Supply Center-Philadelphia Prime Vendor Program and are gradually replacing the old vests, Wojtaszek said.

Float coats

The Mark I vest, known as a "float coat," is authorized for all ships but is primarily worn by sailors working on an aircraft carrier's flight deck because its minimal bulk enables sailors to operate unencumbered, Wojtaszek said. It comes in seven colors, each representing a sailor's specific job, and five sizes.

The vest design is a modified commercial Sportsman's Utility life preserver containing an inflatable bladder placed inside a flame-retardant-treated cotton/nylon vest cover. The washable cover has reflector strips for safety, and a heavy-duty plastic zipper and two buckles to secure the vest.

One size bladder fits all vests and is interchangeable between any of the three companies approved to supply the vest. The vest inflates automatically upon water immersion through an inflator with a carbon dioxide cylinder positioned on the lower front and will self-right the wearer even if he is unconscious. The bladder also can be orally inflated through a tube located on the upper front. Both inflator and oral tube are covered by a flap to protect them from damage.

In an upper pocket, the new vest contains a tethered whistle and strobe light that flashes automatically upon water immersion. The light is visible secured in the pocket or can be removed and stuck on a Velcro shoulder patch to improve the wearer's chances of detection.

Another pocket below the light holds a dye pack used to mark the location of the sailor and a MOBI. After considering several concepts to hold the MOBI device with its antenna, the final design inserted the antenna along an inner loop around the vest's edge leading to the top of the collar. This provides the best signal and also protects the antenna from damage, according to Wojtaszek.

The commercial MOBI technology is able to tell the ship the serial number of the transmitter to determine who is overboard, even if more than one person is in the water, and indicate the direction of the signal up to 1 nautical mile away, Wojtaszek said.

Without the technology, he said it is possible to lose track of a sailor in the open seas, and in some cases not even know he had been blown over the side by jet blast.

"All of these things are pluses that basically can save the guy's life out there," he said.

Inspecting the bladder as part of preventive maintenance is now easier, and sailors don't have to remove the inflator and cylinder, which reduces the risk of failure. Another modification created an opening at the back to allow the D ring safety harness to fit through, and Wojtaszek said the manufacturers liked it and adapted it to their other life preservers.

Foam cells

The orange Inherently Buoyant vest is made in two sizes and uses closed-cell foam. It's bulky and intended for topside sailors on watch who don't need extra mobility, Wojtaszek said.

It has the same MOBI, strobe light, whistle, dye pack and opening in the back, and meets all UL standards for buoyancy.

Of particular importance is sufficient head support in rough, open seas, he said. A unique feature is the vertical collar tabs that when pulled tight give the sailor 1-2 extra inches between the water and the sailor's mouth.


Aside from a pouch attached to a belt that holds a whistle, strobe light and buddy line, the Abandon Ship vest is identical to inflatable belt styles worn around the waist and sold commercially by several manufacturers. It is used in case of an emergency for all surface ships and submarines, according to Wojtaszek.

An inflatable bladder folded out of a blue rugged nylon pouch is manually inflated with a pull-tab trigger inflator discharging a carbon dioxide cylinder or through a mouth tube. Enough of the vests are aboard each ship for everyone.

For more information about the NCTRF or the Soldier Systems Center, please visit the websites: and

This page last updated on 23 January 2004.