Rescue 21's plotting capability also vastly reduces the time it takes for the Coast Guard to compute how far the boat (or the boater) is likely to drift during various weather, wind, current and tidal conditions – a key factor in any rescue effort. Under the old 1970s system, it often took three to four hours to estimate such movements. With Rescue 21, the whole process takes no more than three to five minutes.

PLOTTING SEARCH PATTERNS

The system not only predicts where the boat (or the boater) will end up over the next few hours, but it also plots out the search pattern that a patrol boat or helicopter should follow in looking for the person or the vessel. It provides rescuers with exact coordinates on where to begin the search and how long to stay on a particular course before turning to follow the next leg of the search pattern.

Watchstanders use high-tech communications data to pinpoint boaters in distress.The new system also will bolster the Coast Guard's ability to carry out its homeland security missions – by operating more closely with other armed services as well as with federal, state and local homeland security agencies throughout the United States. And in the 48 contiguous states, it provides portable radio towers for use during natural disasters.

MORE SENSITIVE, EFFECTIVE

By the Coast Guard's own account, the new system already has proven to be dramatically more effective than the one it's replacing. It's able to pick up radio calls that the current equipment misses entirely or home-in on faint static from a keyed microphone, and transmit the information to nearby vessels.

Finding boaters in distress isn't always easy. Coast Guard rescue personnel must spend hours – sometimes days – locating vessels and boaters who have called for help themselves or have been reported by others as missing or in trouble. It often requires scanning large areas of water from patrol-boats or helicopters.

In some cases, mayday messages are garbled. Boat radios fail to transmit clearly or far enough. Boaters who fall overboard frequently are swept by wind and currents to locations far from where they entered the water. Rescue 21 won't overcome those problems entirely, but it is cutting response times in many cases, officials say.

Last month Coasties rescued a 78-year-old man who'd been drifting in a life-raft 20 miles off the Florida coast. Although his small hand-held radio had a transmitting range of only about five miles, Rescue 21 equipment picked up the signal anyway and pinpointed the life-raft – some 15 miles away from where the man had said he was.

A few days before that, the Coast Guard rescued a seven-person crew whose members had become disoriented in the fog off the coast of Wildwood, N.J., after the vessel's GPS receiver had become disabled. Coast Guard radio operators located the 22-foot boat with Rescue 21's new direction-finding equipment.

"Our call traffic has increased significantly in sectors where Rescue 21 has been installed," says Lt. Commander Anderson. "We get more cases because more people are able to reach us – and we're able to locate them more quickly."

GETTING YOUR OWN BOAT READY

Technically, if you already have a VHF-FM marine radio, you won't have to do anything more to equip your boat for Rescue 21. Your existing radio will do the job, and the Coast Guard plans to continue using Channel 16 as the primary channel for emergency distress calls.

But the Coast Guard stresses that you'll get a more effective response if you buy and install a VHF-FM radio equipped with Digital Selective Calling, or DSC. When DSC has been linked to your GPS set or LORAN receiver, it enables you to push a button that automatically transmits your exact position, a description of your vessel and the nature of your distress to the Coast Guard.

The same message also goes to all DSC-equipped vessels in the area, including commercial and recreational vessels. Big ships are required to monitor Channel 70, which carries DSC transmissions, and some towboat companies are equipping their boats with DSC radios. As a result, the Coast Guard can tell which other vessels are in your area when you get into trouble, and ask them to be on the lookout for you.

To make a DSC radio fully effective, you must do two things: register the transceiver and obtain a Mobile Maritime Service Identity (MMSI) number to program into it, and then hook the transceiver up to your GPS set or LORAN receiver. You can both register and get your MMSI number through BoatU.S..

If you already have a Federal Communications Commission license for your VHF-FM radio – not required unless you take your boat to foreign countries – your documentation probably contains an MMSI number. All you have to do is program it into your DSC radio (see your owner's manual for instructions).

Anderson says the next step is to educate the boating public about the new system – particularly on the benefits of buying a VHF-FM radio with the Digital Selective Calling feature and hooking it up to their GPS or LORAN sets. "It's the best thing that people can do to help themselves," he says.