Underwater modems. Whatever next? The U.S. navy is using technology developed by Benthos Inc. to send e-mail from a submarine off the coast of California to a naval base in San Diego.Crusing at a depth of 400 feet, the USS Dolphin was able to send e-mails up to a distance of three miles to a relayer buoy, which transferred them to land, Benthos president and chief executive John L. Coughlin said. It was the first time a submerged and moving submarine was able to communicate without giving away its position by surfacing or raising an antenna. The modem sends digital data underwater using sound energy.The e-mails were sent at a speed of 2,400 bytes per second, slow when compared to desktop computers, but pretty zippy when it comes to underwater sound waves. ?Underwater e-mails are not new, but what makes this technology different is the distance, speed and reliability of the transmission,? Coughlin said.The technology not only has military applications, but can be used by the gas and oil drilling industry, for weather tracking and for other underwater research. It was developed using a grant from the Navy?s Space and Naval Warfare Systems Command Center.