EQUIPMENT USED TO FIND AND SALVAGE SHIPWRECKS
William K. Seliger – August 2008
Although the vast majority of shipwrecks are discovered accidentally by local fishermen and divers, many have also been located through the use of specialized equipment. Once a wreck has been found, additional specialized equipment is often needed perform the salvage operation
Presented here, you will find a discussion of most of the equipment being utilized to both to locate, as well as salvage, shipwrecks today. An attempt is made to present this information in non-technical terms, but of necessity, it contains some technical data. The intent of this presentation is to acquaint the non-technical reader with the various types of equipment available: their use; strengths; shortcomings; relative cost to acquire and use; and the environments for which they are suited. Armed with the knowledge presented herein, the reader should be able to carry on an intelligent discussion about the equipment used for finding and salvaging shipwrecks.
As mentioned in Sunken Treasure How to Find it by Robert F. Marx, local shrimpers and fishermen are often the ones to discover shipwrecks. If you have done research, and know of a shipwreck you wish to locate, the first step is to meet all the local fishermen and divers in the area and see if they have discovered any snags or brought up any objects in their nets which would indicate a shipwreck. They will often have stories of objects, or even have the actual objects that have been found, but don’t realize they indicate the presence of a shipwreck. If this approach fails, depending on the environment, simple and inexpensive approaches can be taken to search for your target shipwreck. These include visual searches with underwater scooters, being towed behind a boat on a towline or a sled, glass bottom boats, aerial surveys, aerial photographic surveys, and today, even satellite surveys. Sophisticated equipment is not as important as thorough research before starting a search or excavation. The idea is to keep overhead down, keep things simple and operate as efficiently as possible with whatever means available.
These methods failing (your target may be completely buried or lying in areas with poor underwater visibility), you may have to resort to using more sophisticated methods for locating it. In this section, the following devices will be discussed: Magnetometers (towed and handheld), Sidescan sonar, Depth Sounder, GPS, Sub-Bottom profiler, Aerial survey, Metal detectors (towed and handheld), Air Lift, Blowers (Mailbox, Barn door), ROV, Remote underwater Camera, Ruggedized laptop computer, survey software, GIS software.