Is This Ascent Rate Alarm Useful?

New on the market is the Miniature Ascent Rate Alarm (MARA), a small, yellow electronic gizmo designed to monitor your ascent rate and reduce your risk of decompression sickness. It attaches to your mask strap and bleeps if you ascend at more than 30 feet per minute. It bleeps again to provide a safety stop at 15 feet. But is it worth 90 bucks?

John Bantin, equipment editor for the British magazine Diver and a frequent Undercurrent contributor, tried out MARA for us. “I found the squawks useful, in that they sounded more urgent as I broke the ascent-rate rules more determinedly. Once I reached the 15-foot mark, I certainly knew it was the place to make the safety stop. Unfortunately, ascending in blue water without any data, I really needed something that would tell me if I unknowingly sank deeper again. This the MARA does not do. This explains why my five-minute safety stops, counted down on my computer and constantly restarted as I regained the 15-foot mark, always seemed to take more than 10 minutes. Whether you need a MARA or not depends on what you normally do during an ascent after a dive.”

“For the experienced diver, MARA is probably of little use, but for the novice or perhaps when diving in very low visibility or at night, it could be an aid for getting your ascent rate right,” says Charles Hood, gear tester for British magazine DIVE. “I heard it through a 5-mil neoprene hood. It can’t be heard by nearby divers, as it transmits the sounds inwards and not all around you.”

MARA’s maker says it’s guaranteed to last for up to five years or 1,000 dives, but it has a non-replaceable battery. (www.masterunderwatertech.com)