Since the days before recorded history, people have been using waterways as a means of transportation. While the very first boats were simple affairs, it wasn’t long before boat building technology became progressively more sophisticated. As people made their watercraft more seaworthy, they found that they were able to go further which enabled them to make new discoveries and eventually led to the necessity for a means to transport cargo. Ships got bigger, and navigation became less of a roll of the dice and more of a science. More ships led to more shipwrecks, which eventually led to wreck exploration. How are these wrecks discovered? Let’s take a look.
Three Million Shipwrecks Are Waiting to Be Discovered
According to UNESCO estimates, there are an estimated three million shipwrecks still waiting to be discovered. The number of wrecks already found is staggering – there are over 65,000 lying off the coasts of North America, and more than 850 off the Azores, and hundreds of thousands more in other locations with some of the oldest having been discovered in the Mediterranean Ocean and the Red Sea.
With oceans covering seventy percent of the planet, the amount of territory to be covered is vast. In some cases, wrecks are discovered accidentally, often by fishermen. In other cases, wreck locations are marked on navigational charts, and fish finding technology aids in pinpointing their exact positions. Some savvy fishermen keep their finds a secret, while others don’t mind sharing. This is how the famous U-869 wreck was located off New Jersey.
Oil and gas companies find new wrecks with regularity. One of the most exciting finds made recently is a group of twelve shipwrecks in the Baltic Sea. One wreck is believed to be 800 years old, while the rest date back to the 17th-19th centuries. They have been photographed and are well-preserved, but at depths of about 120 meters, they are out of reach of most divers.
Many “new” wreck discoveries have been known for a long time, but it is only with advances in technology that their exact locations have been pinpointed, and as mixed gas and better diving equipment allows us to extend both depth and bottom time, some sites that were previously too deep to be explored are now regularly visited by technical divers.
Technology for Finding Shipwrecks
There are a number of technologies that allow wreck hunters to find new shipwrecks. While most boat owners have fish finders, which can be helpful, more advanced methods are often costly.
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Sonar has been in use for decades, but it only points out abnormalities on the ocean floor. While sonar sometimes turns up nothing more than rock formations or other geologic features, it is a valuable tool for scanning areas where wrecks could be.
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Side Scan Sonar – This is a big step up from old-fashioned sonar. Towed behind wreck hunters’ boats, side scan sonar provides shadowy images of objects on the ocean floor. Special software has been developed to make the process of identifying wrecks easier.
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Metal Detectors and Magnetometers – Towable metal detectors and magnetometers are valuable tools for locating newer shipwrecks, allowing large areas to be surveyed with relative speed. When combined with side scan sonar, this tool makes positive identification faster and easier.
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Echo Sounders – these instruments use sound waves at a variety of frequencies to create a profile of objects underwater. Sometimes called acoustic sonar, this technology has been developed to enable the discovery of some items buried beneath the seabed. Initially developed to help locate mines, it is now being used to survey shipwrecks.
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ROV’s – Remotely Operated Underwater Vehicles – these unmanned submersibles are tethered to research vessels and are capable of capturing images and providing technical information to human operators. They are often equipped with different sonar and magnetometer equipment, cameras, cutting and manipulating arms, and instruments for measuring water clarity, temperature, light penetration, and chemical makeup. First developed in the 1950’s, they are used for a variety of applications. Micro ROV’s weigh about 3 kilograms, while the largest are designed for heavy industrial use and can dive to about 6,000 meters.
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AUV’s – Autonomous Underwater Vehicles equipped with a variety of instruments, including cameras, are computer controlled. Self-guided, and with their own power source, they are capable of functioning in water too shallow for boats to explore, and too deep for human divers or ROV’s. First developed in 1957, AUV’s carry out a variety of underwater tasks, enabling us to explore safely. Most are battery operated and some are capable of going long distances before retrieval.
While most wreck hunters use surface vessels to find new shipwrecks, some have gone underwater, using specially equipped submarines to sweep large areas in search of deep wrecks. While many of the deepest are out of divers’ reach, submersibles are beginning to offer trips to some of the most famous sites. For example, one can now take a trip to the Titanic, which is resting 3,800 meters beneath the surface.
Many of the wrecks we dive on today have been found using a variety of these methods, while some have been known since their sinking. And, while some wrecks have simply been stumbled upon, some of the most fabled shipwrecks’ general whereabouts are matters of common knowledge. Still, pinpointing a wreck can be like finding a needle in a haystack; particularly when you consider the fact that GPS has only been in use for a very short amount of time. Ancient mariners relied on landmarks and natural navigation techniques, so when a wreck happened, limited information was available. And like the old “telephone game” where information is passed from one person to the next, much is lost in translation.
If you are interested in finding new wrecks, the odds are in your favor. Divers with plenty of resources such as navigational charts and solid historic information, plenty of time on their hands, and a seaworthy vessel equipped with even simple fish finding technology can locate wrecks with relative ease. Hobby ROV’s and AUV’s can be constructed with simple technological knowhow, and metal detectors are much less costly than they once were. While you might not find the next Edmund Fitzgerald or Andrea Doria, you could find one of the many humbler wrecks that exist in depths that are diveable today. Good luck, and happy hunting!