I remember a lake dive I did many years ago around the site of an old logging camp that had since been reclaimed by the forest. I was a relatively new diver and as I swam over the packed mud bottom I came across an old double-bladed axe head with part of the handle still intact. Excited by my find, I pushed on in search of more treasure. At times I crawled across the bottom by digging the axe head into the thick mud and pulled myself along without much thought as to what might lie beneath the surface. Suddenly I dug the axe head into the bottom and heard a resounding crunch. When I cleared away the mud I found to my dismay that I had put the axe head through the acid-etched glass chimney of a large oil lamp. The metal base was still intact but the chimney was destroyed.

I was reminded of this incident on a dive recently as I cruised over another sandy bottom in search of "treasure". This time I was in the ocean and instead of an axe, I was using the Tesoro PIranha metal detector, a much better tool for the job.

The promise of treasure has lured men and women to the depths for centuries, but not all treasure is made of gold, silver and precious stones. To some it is old bottles or artifacts found around the sites of old piers and logging camps and I know a few divers who enjoy the sometimes lucrative hobby of retrieving fishing tackle.

The search for any metal objects can be made simpler with the Tesoro PIranha, a very versatile tool which can be used on land or to depths of 200'. The PIranha is simple to use but does take a little practice. At one end is a standard 8" search coil which can be substituted with either a 7" or a 10 1/2" search coil. The angle of the search coil can be adjusted and each coil has its own uses but for general searching the standard coil was ample.

The length of the PIranha can be adjusted and while diving I found it easier to have it as short as possible, about 39 inches long. Mounted on the shaft of the PIranha and connected by wire to the search coil is the O-ring sealed detector housing and control panel. The housing also stores the 8 AA batteries that power the unit. From the control housing a coiled wire leads to a set of headphones which are worn underwater.

The trick to using the PIranha successfully is in tuning it. For underwater use it was necessary to turn up the volume to between half and three quarters of full volume to ensure that when I came across a hidden target, I could hear the beep through my hood and over breathing and bubble noise. The volume adjustment is found in the control housing so must be set prior to the dive. Once I was settled on the bottom I put the headphones on and adjusted the threshold control until I was just able to hear a steady tone through the headphones or sometimes I adjusted the threshold control just slightly to where I was not able to hear the steady tone. As I cruised over the bottom I tried to keep the coil about two or three inches above the sand with a steady arc of about two or three feet. The PIranha is very lightweight and well balanced so holding it out in front of me was not tiring. The control housing can be removed from the shaft and belt mounted. It wasn't long before the PIranha started beeping on what, at first glance, looked to me like a partially buried barnacle-encrusted rock but on closer examination turned out to be a 10 lb. lead cannonball fishing weight. At another point during the dive I came across a small rocky reef heavily covered in broad leaf algae. As I passed the PIranha over the thick foliage, beeping helped me pinpoint two nice fishing lures and a new flasher. Not only were they retrieved but they were retrieved with a minimum of disturbance to the kelp which after all is home to a variety of creatures. Not everything I found on my dives with the PIranha was treasure. My "haul", besides a nice assortment of fishing tackle, included one wheel hub, a car's rear axle, an old crab trap and several tin cans. On one hand I had found some useful and valuable objects, while on the other I couldn't help being reminded of people's indifference to the environment.

With the Tesoro PIranha, a whole new area of diving can be opened up whether you are scouring the beaches, searching streams for gold, retrieving fishing lures or exploring the ocean floor. For more information contact Jetcom Communications, 1-800-665-0051.

DIVER Magazine would like to thank Divers World of Vancouver, B.C. for their assistance with this article.