Capt. Dan Berg's Wreck Valley Collection   

FINDING NEW WRECKS
By Capt. Dan Berg

Finding a virgin shipwreck is a dream of all wreck divers. Many wrecks have been located by divers just exploring new areas or checking out new loran numbers supplied by local fisherman. The method of search is as varied as the type of vessels that sail the sea. Most successful searches, however, start with a lot of thorough research. Then, when a likely area is derived, the remains can be located with machines such as side scan sonars or proton magnetometers or less expensive equipment like a depth recorder or the affordable, new three dimensional sonar. Other shallow clear water search methods include towing a diver on a sled while the boat does a grid of the area. This method is affectionately called, "towing shark bait". Aerial surveys can also be very helpful, using aircraft, helicopters or even a hot air balloon as Edna and Teddy Tucker did in Bermuda to locate many old wrecks. Aerial surveys should be done no higher than500 feet. Polarized sunglasses are important as is a good calm day with little surface chop.

Getting back to the more scientific methods, let's first discuss side scan sonar. First of all, these units are very expensive, so they are not common place in the sport diving community. Some are owned and operated by treasure hunters, and these machines are worth their weight in gold. Basically, most side scan sonars use a tow fish which is towed behind the boat at a determined depth. The fish contains transmitting circuitry that sends out high frequency bursts of acoustic energy which project along the sea bed on both sides of the boat. Any object that is not buried, like a shipwreck, or a topographic feature on the sea bed produces echoes which are received by a transducer. This information is often computer enhanced to give a detailed image of the wreck. Side scan sonar requires an experienced operator. Proton Magnetometers, which are considerably less expensive, measure the strength of the area's magnetic field instead of looking for topographic features. The earth's magnetic field is changed locally by the presence of any ferrous object, like the steel in a shipwreck. The amount of change is proportional to the amount of ferrous iron. These machines, which also utilize a tow fish, can find any ferrous metals such as cannons, hull plates, and anchors, even when they are buried beneath the ocean floor. Magnetometers can find wrecks, depending on the amount of iron content, up to1,000 feet away.

Remember, before buying any expensive equipment or spending days on the boat searching an area, do your homework. Research can narrow the search area down and save countless hours of wasted time.

 

The Shipwreck Diving E-Book  Instant Downloadable E-Book  Shipwreck Diving, by Capt. Dan Berg is a complete how to book about the sport of wreck diving. This book is packed with information and heavily illustrated with over 80 sensational color photographs.

All photographs, sketches, images and text

Copyright Capt. Dan Berg / Aqua Explorers Inc

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