Finding your way back from whence you came can be quite an important aspect of a dive. The Uwatec Neverlost, which has just been voted Innovation of the Year by Diver readers clearly impressed by the concept, promises to make this easy. It comprises a beacon or "boat unit" and a "diver unit", and works by ultrasound.
Such a system could be of particular help to wreck divers who prefer to get back to their shotlines before making an ascent, or night divers who would like to be sure of locating their point of entry, whether it be a moored boat or shore access.
The beacon emits a signal on one of four pre-chosen frequencies and the diver unit registers the strength, giving both direction and distance. You can scan for other units which might be in use on a site before choosing which frequency to use.
An LCD on the diver unit indicates whether it is being pointed at the beacon and the number of bars on the display gives a progressive indication of signal strength. Pressing the control button on the unit translates this into an approximate distance. There are two range settings, switchable during the dive.
The Neverlost diver unit is said to be able to pick up the ultra-sonic signal of the beacon from as far as 300m, so it should suit most wreck dives. I tried it successfully over more than 150m. However, it works by line of sight, so make sure to attach the beacon so that it cannot be obscured by solid objects.
Part of the art of using ultrasonics is knowing where to deploy the beacon. I found that it worked best on a line between 5 and 7m from the surface. That way its signal did not reflect intermittently from the broken underside of the surface, yet the unit was high enough to "see" me above the topography of the sea bottom. Don't expect simply to chuck it in and then find it later!
Up to 30 receivers will work from one beacon, and the UK distributors hope that dive clubs will buy one so that each member can then buy a locator. Otherwise its obvious market is the liveaboard or day dive boat. The manufacturer would clearly like to see boat-based dive operators worldwide buying beacons and supplying dive units to their customers. That, however, would represent quite a substantial investment.
Both units are big, solid pieces of equipment, each around the size of a good diver's light. Don't confuse them with those cheap sonic devices available from the Far East. My companions on a Red Sea night dive last year will remember me climbing back into the boat suffering from severe sense-of-humour failure when I lost such a cheap beacon. Luckily it had a little tell-tale red light that enabled the crew to spot it from the RIB in the dark later, so I was able to dive back down and get it. In the event the distributor of that one decided not to import it.
After using the Neverlost for a while you get to be able to distinguish between direct readings from the beacon and those that have been reflected from other surfaces such as nearby coral reefs or rocks. I reckon it would be less help if one was in a hurry (low on air, for example) but if you took your time it would probably get you safely home.
One diver decided to stick with me because he knew I was unlikely to get lost. However, when he stopped to take a photograph I disappeared from his view, and he had to resurface several times before getting safely back to the swim platform. I had no such problems!
Provided that you find yourself in the right circumstances, with no other surfaces off which the ultrasonics can reflect, the Neverlost works well. But be on the safe side and use a compass too.
A pair of Neverlost boat and diver units costs Ž£595 and additional diver units cost Ž£300 each.
