Underwater: mines, improvided explosives. a threat to global commerce?

• Author: Truver, Scott C.
• Position: COMMENTARY

The United States confronts the formidable task of protecting some 95,000 miles of coastlines and thousands of miles of inland waterways, including 361 ports. The nation's maritime economic zone comprises more than 3.4 million square miles of ocean space and at any time is cluttered with thousands of naval warships, commercial vessels, fishing boats, tugs, ferries and pleasure craft.

Mines and underwater improvised explosive devices can be placed surreptitiously in channels and harbors for spectacular effects--against the Staten Island Ferry crammed with 2,500 commuters during an evening rush hour or a cruise ship with 4,000 vacationers and crew on board leaving the port of Miami or Seattle. Mines can greatly harm the flow of trade. More than 90 percent of U.S. exports and imports transits U.S. ports. The consequences from just a few mines could be catastrophic. Even if no ships were sunk or damaged, explosions in a few key ports on East, Gulf, and West Coasts and in the Saint Lawrence Seaway, would have a chilling effect on commercial shipping from increased insurance costs and vessel lay-days.

And the economic tremors would reverberate throughout the nation and among trading partners overseas.

Mines are easy to acquire or build, and are relatively cheap, ranging from a few tens of dollars to $25,000 for the most advanced weapons. They can be deployed by aircraft, submarines and surface vessels.

They are designed for operations from the surf zone (less than 10-foot water depth) to deep water (greater than 200 feet). They can range from a few pounds to several tons of high explosive and can have a variety of firing mechanisms, including remote control and command, contact, magnetic, acoustic, seismic or pressure.

Mines can be buoyant and suspended, close-tethered to the bottom, resting on the bottom or even buried under sediment to confound mine hunting and sweeping. Some mines are mobile, capable of being launched from submarines thousands of yards from intended minefields, while others have torpedo or rocket-propelled warheads that dramatically expand potential damage zones against submarine and surface targets.

Limpet mines are designed to be placed directly on targets by combat swimmers or, in the future, unmanned undersea vehicles. Old mines can be refitted with modern, highly sophisticated components and all mines can be equipped with counter-countermeasure features to frustrate sweeping and hunting operations. They can be fabricated...