CDs: The Ideal Surface-Detection Aid?

As he wrote in Britain’s DIVE magazine last December, dive boat captain Fred Buckingham was cruising the open waters near Penzance, England, when his radar screen showed a target approaching dead ahead. It was broad daylight and Buckingham could see for miles, so he assumed his radar was acting up and tried to adjust it, but to no avail. As the boat moved closer to its “mark,” Buckingham spotted a yellow marker from the Penzance Sailing Club. On closer inspection, he saw that the marker had a compact disc stuck on it and assumed it was what had caused the radar echo.

Despite its lack of heft, a CD’s smooth, reflective surface may attract enough radar waves to bounce them back to the transmitter. That gave Buckingham the idea that CDs could be a handy rescue tool for divers. When attached to a diver’s safety sausage, they could give boat captains a radar position on all the divers they are responsible for.

Safety sausages could use some assistance. Even a 150-foot separation in choppy waters makes it difficult for a skipper to keep tabs on every diver, with some drifting at different speed and directions, and others still submerged. The use of CDs could allow captains to “see” all of their divers in all types of weather.

To test his theory, Buckingham had three buddy pairs attach CDs to their safety sausages before diving, while the radar gain was adjusted manually. When the divers deployed their marker buoys, all of them showed up on the radar. Buckingham dropped them into the water about 225 feet apart. He saw that divers didn’t always show up on radar if their CDs weren’t facing the boat, but if the CD was pointed directly toward the craft, the radar gave a very strong reading. In fact, when two divers were placed together in the water with their CDs facing the radar, Buckingham received two clear and distinct readings.

Buckingham, who recently spent hundreds of dollars for his boat’s radar reflector, now regrets he didn’t make it out of CDs. These CD-equipped safety sausages still need to be tested in rough conditions, but you may want to think twice before throwing your old music collection away.

This story was excerpted by “Surface Protection Aid” written by Fred Buckingham and published in DIVE magazine.