4. Underwater Archeology

The archeologists taking note of the remains of an English shipwreck in Champotón, Campeche.

If extracting ancient objects from the bottom of the ocean, cenotes or lagoons is not considered underwater archeology, then, what is it all about?

In essence, it is a specialty that is looking to broaden the knowledge we have on past cultures trough the historical remains that are found underwater. Archeologists want to be familiar with their subjects and to do so, they use all the information that an object can provide and, what is more important, not only of the object itself, but of all the elements surrounding it and that when put together, become an archeological site.

For example, if we found the remains of a vessel´s rudder that sank in the 16th Century and we extracted it without registering where it was found and what was its position relating to the rest of the objects, we would be destroying clues to understand what happened hundreds of years ago. The rudder, by being the key piece of a ship when giving direction, was always found in the stern, i.e., in the rear part of the vessel.

By eliminating this object from the context, meaning from the place where it was found originally, how do we recognize the stern from the bow? In other words, how do we understand this group of pieces of timber and metallic elements if someone extracts certain parts of the puzzle?

Remaining of the engine of a modern vessel that had an accident in Banco Chinchorro, in the State of Quintana Roo.

Underwater archeology represents a series of challenges. One of the biggest problems of underwater archeology is the time that can be destined to work in submerged sites. The main restriction is the provision of air, as when diving in major depths, the stay time becomes shorter.

In the ocean we must take into account various circumstances, such as marine currents and scarce visibility, factors that can make the archeologist's work difficult. In the same way, marine fauna can present certain dangers. Some species, such as the moray or scorpion fish who like to hide amongst the tubes and wood hollows, the stingrays who get camouflaged under the sand. If you are not cautious when registering or when you observe, the intruder, in other words, the archeologist could get hurt.

Maybe the most feared aquatic animal is the shark. Nevertheless, when one of these appears, it is important to keep calm, to stay put at the bottom and to observe its movements. Except rare occasions, sharks do not find divers appetizing; actually what they perceive is a strange being, of considerable size that sends out bubbles, something they rather stay away from.

In the case of flooded caves and cenotes, the difficulties are different. To dive in the cave systems is like going blindfolded into a labyrinth. Occasionally the tunnels get too narrow or you reach a point where you need to go back before the air in your tank finishes. In these environments, one of the major dangers can be crocodiles.

Due to these risk factors, there are diving rules that must never be forgotten. One of the main rules is to never dive alone, as a fellow team member would be paying attention to any problems that might occur during the immersion. It is very important to respect underwater life. The small diving knives are only purposed to cut ropes or nets in case the diver is stuck, but never to hurt or hunt any animal. In the coral reef zones you must dive very cautiously not to cause damages, as the coral colonies take decades to re-generate and the coral reefs take hundreds of years to go back being a healthy ecosystem. Respect to underwater life is fundamental to an underwater archeologist and as they should be conscious, firstly of the privilege of submerging into a different world to their own and secondly, of the importance of taking good care of it so that they don´t interfere with its natural balance. Finally, the fish, the corals and the algae find a new habitat in the remains of shipwrecked ships. What was once the residue of a tragedy it is now part of the underwater landscape.

On top of the diving rules and of the ethics towards underwater life, an underwater archeologist needs certain specialized techniques to search and locate the submerged cultural remains. If the extension of the ocean is so big, then where do we start looking? What does an underwater archeologist do once he locates something of scientific interest?

4.1 Searching and Identification Techniques

Underwater archeological project in the Moon Lagoon located in the Nevado de Toluca, State of Mexico.

Besides being a scientific discipline, underwater archeology is something fascinating that must follow certain requirements, such as taking thorough precautions, to strictly fulfill the diving rules and to work in a systematic manner so as not to loose information.

First we need to search. Sometimes fishermen and recreational divers of a community inform the archeologists on their findings, which is highly valuable, as this saves them time, effort and economical resources.

But if there is no direct reference to the location of cultural historical remains, then, to be able to locate them, they use tracking devices in the water. From the simplest system, such as the towing planks system to a more sophisticated one, such as the systems of geophysical survey.

The towing planks are, in fact, very simple systems of tugging on the surface of the water so that the diver can visually locate something. The archeologist wears a diving mask and a snorkel, sits on a small plank that is tied by a cable to a boat, holds himself to some handles located on an acrylic plank (so that he can observe) and when he is ready gives out a signal.

Carefully and at very low speed, they are tugged on the surface of the water. When he takes note of something interesting at the bottom of the sea, he gives out a signal and he is released from the plank to do free diving and verifying if what he saw is of archeological interest.

At first, it is not easy to identify the objects, as after a long time they tend to be covered with coral or tend to be concealed amongst marine life. The secret is to remember that in nature there are no geometrical shapes, in other words, if you observe a squared coral formation or a perfectly round one, then, underneath it there is certainly some metallic geometrical shaped object.

With time and experience, the archeologist's eye becomes trained until he it is able to quickly recognize the cultural remains of shipwrecked vessels.

This system is useful in small depth waters with good visibility. There are, nevertheless, two main restrictions: it is not possible to cover large extensions and the tracking time limits itself to the archeologist's or diver's ability to endure certain time on the tug. This type of tracking can only be done trough free diving, in other words, with a snorkel and flippers, as during the maneuvers, the diver constantly changes his depth, which would be dangerous if it was to be done with SCUBA equipment.

Use of metal detectors.

The method changes when you need to cover larger extensions, to search in deep waters or with little visibility, or if there is a dangerous fauna. For it, the archeologist uses high tech technology, meaning that he uses a system of geophysical survey and remote sensoring.

4.2 Underwater Archeological Work Techniques

The most relevant thing about the system of geophysical survey and remote sensoring is that it is not an intrusive process; in other words, through the use of measuring instruments of the bottom's characteristics it is possible to know if there are cultural remains of historical value underwater. It is a major vessel that is used in the plank tugging system, a group of devices made out of a caesium magnetometer; digital side scan sonar and an echo sounding are tugged on the water surface to capture certain data on the seafloor.

With the magnetometer you can identify elements with a ferrous content, such as cannons, bullets, anchors or even smaller pieces such as the ironworks or nailing of a ship.

As far as it is concerned, the sonar sends out sound signals that can draw in relief the seafloor and detect the presence of historical and cultural remains.

Usage of a magnetometer.

Reading of an echosounder (left). Display of a sonar (right).

Lastly, the echo sounding is used to know the depth of the place where we are sailing, as if a sudden change of depth would occur, the devices that are being tugged can collide, get damaged or even get lost.

Same as with the tugging planks, there must be a previous, systematically made plan of the area where the activity will take place. In both cases, before you start the tracking, you must take important facts into account, such as the current, the waves, the wind and the depth of the potential tracking and searching area. A lapse of concentration could provoke the archeologists to end up in a shipwreck as they try to study maritime accidents form the past. Doing this part of the job in a systematic manner helps to guarantee that the whole area has been checked and to know if there is or if there isn´t any archeological material in it and where exactly would it be located in.

As it was mentioned before, the support of the people that is daily in contact with bodies of water turns out to be valuable for archeologists. The fishermen and the recreational divers, during their activities, can find the material historical remains of maritime accidents or, in the case of flooded caves or cenotes, with the evidence of pre-historical or prehispanic culture. Even if they do not always give notice of this, when they do participate along with the scientific community a good working team is created.

When receiving news on a sea finding and if the informer provides the location of the site, another method of research and location is then used. Once the archeologists are in the précised area, they map a work plan before the immersion. First through free-diving, by using led as way of ballasts in order to submerge, they submerge by withholding their breath in apnea to see if they can observe anything of a cultural characteristic.

Depending on the visibility, the divers position themselves next to the distance tape measures that can vary from half a meter to five meters long, and with a previously agreed signal they start to move forward in the same direction, without losing the previously established formation, trying to take the tape at ground level so that it doesn´t get stuck. In case they run into a natural obstacle, they dodge it to continue their route until they complete a circle. If in that operation they do not locate anything, they repeat the operation until they conclude the scheduled diving time or until one of the researchers has problems with his air supply or temperature.

This is a photographical register of the "Boris" site. You can appreciate the ballast mound of the rests of the vessel.

The other variant of the route with a determined orientation is used to reach bigger extensions. Just as the latter, the archeologists take a tape measure and locate themselves at determined distances, but instead of forming a circle, they form a line by taking a fixed course with their compass. Once an area is searched thoroughly and there was no success, they go back by taking the opposite course that the one taken at the beginning but changing its quadrant. Again, the decision of the distance to be covered depends on factors of visibility, tank duration and the diver's condition.

And what happens if they find something?

Example of a Prehispanic ceramic piece located at a cenote at Yucatan´s Peninsula.

Under any of the research and prospecting systems, once the evidence is located, the next step is the register.

This stage of the archeological work is very important as if it is rigorously and carefully made, the obtained data will become a valuable and essential tool for further research, when once on solid ground they try to solve the puzzle. The site to be studied is marked with a flag and then with a buoy in order to have a fixed point of reference. Before you start the register by means of drawings, video takes are taken by slowly going through the area to obtain the largest amount of possible detail that can then be analyzed at the office as many times as necessary.

The following step is to do an exploration around all the area where the material remains are spread. This is necessary so as to be able to identify the boundaries of the place that will be studied. Sometimes, maritime accidents leave evidence in very extensive areas, as before they shipwreck they tend to throw heavy material overboard to free the vessel. Then, we proceed to setting a tape measure along the area that holds the evidence so as to be able to divide it into quadrants.

Archeologist takes note of the route and distance of the tape, necessary data to then sketch the site's scale drawings. With a more complete panorama on the archeological scene and before starting the detailed register, the researchers go on the motorboat so as to discuss the work plan to follow without the limits that being submerged requires. The quadrants are spread, they choose the person that will draw, and then chose the person to take the measurements and establish a risk level according to the priorities of the investigation.

Once they have a well assembled working plan, the archeologists prepare themselves for the next immersion. What are the tools needed by an underwater archeologist? Just as a ground archeologist, he requires of equipment to be able to draw measure and guide himself, but one that can be used underwater.

On a small acrylic plank, the archeologist sticks with tape a piece of waterproof herculene paper on which it is possible to draw very well. With an elastic band holding the small plank he ties a pencil or an automatic pencil that has no metallic parts so as to avoid it rusting; not to lose the small plank, he holds it with a bronze broach to one of the rings on his diving vest.

He also ties a plastic measuring tape, a compass and inside of a net he places other useful tools in case they need to mark something, such as small flags or even an inflatable buoy. Those in charge of filming the work and of taking pictures of the pieces or materials descend with waterproof cameras and even sometimes with lights and a tripod. Something that the photographers must not forget is an arrow-shaped ladder that is places next to the object and is positioned to face north, so as its photographic shots can reflect the size of the object and its orientation, something that will be of great help to the research.

Once the working plan is ready and their equipments are assigned, the immersion time is determined and the proceedings to follow in case a diver gets separated from his workmate are set. The safety protocol is very important, as once underneath the water, communication can be confusing. Now they are ready to submerge and start working.

Underwater archeology can be something very exciting. The first sensation is that one of freshness when the water filtrates in small threads inside the neoprene suit. Listening to our own breathing, seeing the bubbles surrounding us when we exhale, floating on a new world and finally reaching the bottom, are unforgettable experiences. The show can be magical, as marine life gets hold of the ships remains, transforms them and decorates them to finally turn them into their own habitat.

An underwater archeologist finds the evidence disguised, and so, as a detective, he needs to start by deducing what is this show he is watching all about.

When he gathers the experience, he learns to identify the objects and establishes register priorities. Occasionally he only sketches in order to get the basic information of the site but sometimes a map of the place is elaborated.

Legends about treasure chests filled with jewels and golden coins have created the tendency to easily confuse an archeologist with treasure hunters and led to think that the main function of archeology is to excavate in order to only extract things. In fact, experience shows that the best thing for the objects is to remain underwater; in theory; from the moment they sank they suffer a process change in their chemical properties until they reach stability. To take them out of the water would mean to expose them again to an abrupt change of surroundings, and they can go out of shape, deteriorate or even go to pieces, as in the case of the anchors and cannons that we can see at some ports.

In another hand, to take them out is also a great responsibility, as the researcher must guarantee a process of stabilization and conservation that can last for years, something that can turn to be very costly. Also, after the extraction, a place to store it or else exhibit it needs to be found. We add this to the fact that a piece with no information doesn´t say much, for what it feels the need to make a research and to bring sense to all the extraction work and its following processes.

These days, the idea of only extracting one object in case it is found in danger of being sacked or if it is a diagnosed piece, still applies. In other words, it must be a key object that can provide chronological information of cultural origin or affiliation. As it can be appreciated, to take an object out of the water is a decision that requires putting several elements on the balance and if it is decided to do so, it must be done with responsibility.

4.3 Methodology

A.- Route

Practice of photographical registering in a swimming pool.

Actually, the underwater work is minimal if it is compared to the amount of work and hours that are destined later in the office. The result of the underwater register, the drawings and the video and photographical images will be the main elements to look for when searching for the answers to the stated questions made by the archeologists.

Before they begin with the research, the archeologists must decide what is that they want to know about these sites, meaning that they need to ask themselves a question and search for its answer. Depending on this question they will perform the necessary tests and research.

For example, if they want to know the site´s chronology, they will then focus their attention in certain key objects. Occasionally, cannons have melting dates; some nautical objects such as the astrolabe also carry the mark of the year they were made and if coins are found, it is possible they are also marked.

These three examples can provide, at least, a limiting year of the period belonging to the vessel that carried them, because to be able to know the date of the shipwreck you need to go to the historical archives and look for the event's file, if it even exists. That is to say, a ship can transport a 16th Century cannon but shipwrecked in the following century, as the artillery was a material that could last for more than a hundred years. The same thing happened with nautical instruments; their elaboration was quite costly and the material, generally bronze, allowed a lasting life, unless the technology evolved and other sorts of instruments were needed.

B.- Reconnaissance

To investigate on the origins of a ship and its cultural affiliation, in other words, the place where it belonged, other elements are taken into account. The origins and belongings do not refer necessarily to the same place. For example, the ship could belong to the British Empire but made stops in several harbors along its route. At the moment of the shipwreck, in its hold, it would contain merchandise from the last harbor it stopped at.

The challenge really becomes difficult as a Spanish Empire ship could be transporting English cannons, hold American merchandise and carry instruments built in Holland. When faced with these information labyrinths, the researcher needs to take many elements into account, analyze them and deduce what place is given to each of the puzzle's pieces. That is why the team that makes up the research group devoted to the study of underwater archeology involves more disciplines besides the one in archeology.

Bronze 16Th Century cannon (Half culverin) found at Cayo Nuevo, Sonda de Campeche.

C.- Register and recovery of materials

Besides needing archeologists, also historians, anthropologists, biologists, geophysicists, oceanologists and all of the sciences that can contribute to the understanding of the human relationship to its aquatic surroundings are needed. That is how underwater archeology becomes a multidisciplinary branch of study where we search to relate the participating sciences to obtain a more complete panorama that takes into account the different facets of its main objective.

For example, the research on historical archives is fundamental. When an archeologist registers underwater, when he sees the remains of some cultural event, he asks a lot of questions. What sort of ship was it? Where did it set sail from? Who were the ones sailing it? Why did it shipwrecked? How to identify all of those material fragments on something that happened hundreds of years ago? The answers lay kept amongst the thousands of documents kept in the archives. Luckily for the researcher, the administration in Colonial times was extremely bureaucratic; therefore, all of their activities generated a bulky quantity of files in order to do the necessary paperwork to be able to sail towards the New World. The institution in charge was the House of Trade (Casa de la Contratación de las Indias), located in Seville, Spain.

17th century engraving where the rescue of a shipwrecked galleon is illustrated.

From there, government employees supervised and authorized the trade between both sides of the Atlantic; they performed inspections in the fleets before they set sail and they followed anything related to sailing, including maritime accidents. That is why it is possible, if you look patiently, to find the files that hold the constructive characteristics of the ships, the name of the owners, the list of passengers and crew, the merchandise, artillery, list of nautical instruments, etc. In some cases, it is even possible to find out what the crew ate. But to be able to understand what happened when they were sailing and why they never reached their harbor of destiny, the testimonies of the survivors of the accident, if there was one, are part of extremely important information.

But not all of the information is found registered in ancient papers. That is why it is important to consider that there are cultural behaviors that still remain to our days. That is why the anthropological work with fishermen and related towns linked to the aquatic environments are very important, whether they are maritime or inland water bodies such as cenotes, lagoons or rivers. Those who usually work in the water have greater chances of locating these submerged cultural remains and, if they share this information with the archeologists, they will save them a huge amount of work.

Nevertheless, researchers are also interested in learning how these people conceive the ocean or the bodies of water, the mythology surrounding it, the products that they obtain for their nourishment and trade, the way they sail and even how sometimes sea experience can be more useful than technology.

Many of these world vision related-activities and fragments are ancestral experiences concealed amongst modern life forms. So if the analysis of the objects and of the documents leave out questions unanswered, the thorough study of the life of certain groups and their relationship with water as a main axis on their activities is a way to continue to build our past 's History.

As for biologists, they contribute to the study of communities that live amongst the underwater material remains. Occasionally, when they transform them into their homes, they help wood or metal stabilize in their chemical processes of deterioration when they get in contact with water and its components. But sometimes the contrary might occur. Some crabs happen to feed off wood and with their little pincers they can turn the remains of a sunken ship into a real feast.

A biologist gathering species samples and noting physical-chemical data parameters.

Identifying the species that will help preserve the underwater conservation and those that will raise the speed of deterioration is vital in order to take extraction decisions. In another hand, if you perform controlled experiments on how to interact with the natural environment and with the material historical remains that can be monitored in the time it takes, for example, for the coral to build a colony or even a reef on top of the metallic objects. This information is very useful to extrapolate and, with the experiment's information, to be able to deduce how long has the studied material been underwater.

With it, a rough chronology of the event can be set out. It is also important to study the preferences of underwater communities, as the objects made out of different materials are inhabited and transformed by very diverse species. According to the material, there will be a certain type of fish, coral or algae appearing. This fact has even given way to the formation of artificial reefs.

An image of the remains of a shipwreck known as "La Carmelita", located in Campeche´s coast.

It is not enough to understand the human groups that sailed trough the sea or that used bodies of water to perform rituals or to feed themselves, but it is also vital that we study the animals that, are totally alienated to the intentions of men, and that by recycling their waste in order to live or to feed out of the sea, and the natural forces that also have a voice in this story. Geophysics is important to develop sophisticated systems of water research. As we saw it, such a fast technological development in the last years has allowed a lift in the activities that before, used to be unthinkable. The machines that were invented to explore the marine depths, such as the magnetron and the sonar, allow us to search large water extensions, by supplying a shorter time of effort for the divers.

These machines register the magnetic information of the water floor and they can detect, trough sound emissions, the presence of objects lying under the sea. Nevertheless, not just anyone can interpret this information. It is necessary to go to a specialist so that he can read on screen the different colors and number so as to translate them into understandable concepts for the archeologist.

The ocean has a life of its own, and to be able to understand it, we need oceanologists. They are able to study the currents and behavior of the sea when dealing with a climate phenomenon. For instance, when there is bad weather, such as northern winds or storms, the direction of a current can radically change; this makes the ships that go trough the sea to modify their navigation strategy so as not to perish in the waters. Even a really strong current could provoke the remains of a vessel to spread on the marine bed with larger distances between them.

In conclusion, underwater archeological research is a complex equation between different sciences and knowledge. You need to be acquainted with antique ships, of the social customs of those that sailed as well as of their technical knowledge, to understand their rituals, trading and feeding systems, to recognize the habits of the aquatic species and the way they associate with submerged cultural remains, and in another hand, to be able to coexist wit sophisticated sciences such as geophysics and the oceanography to be able to understand the complexity of the sea's behavior and of its natural forces.

With time, the new appearing underwater archeology has started to get specialized, as it is obvious that the different cultures all over the world can specifically relate to their aquatic environments. In order to increase knowledge on past cultures, whose cultural remains lay underwater, it was decided to define different fields of application.

In theory, underwater archeology includes the large spectrum of studies covering the study of immersed cultural remains, which can be found in any marine or inland body of water and also on islands The aquatic spaces would then be the cenotes, lakes, rivers or submerged caves. For the marine environments, two sub-specialties were created: underwater archeology and nautical archeology.

In general, maritime archeology studies the material remains belonging to ships that suffered an accident during their crossing and as a result of multiple factors: human error during the sailing, the deterioration of the ships or because of a natural phenomenon. Underwater archeologists refer to shipwrecks as "time capsules", as they say that the loss of a ship can make everything that was on board deposits itself at the same time as the ship's remains in the seabed, which gives a sensation of it freezing in a precise moment in time.

Register of an almirantazgo-typed anchor at the site known as "Boris" located in Banco Chinchorro, Quitana Roo.

In the other hand, nautical archeology only studies the technological aspect of sailing. The archeological findings frequently reveal parts of ships, building constructions and, in some occasions, of vessel types that were completely unknown.

A conic-shaped copal found during the underwater archeological season of the Underwater Archeology Sub-direction, at the Nevado de Toluca, in the State of Mexico.

The field of action in nautical archeology covers submerged and out of the water contexts, where there was cultural evidence of vessels, like ships that ran aground, decks, shipyards or other places where ships were built or repaired.

Registry of sea-extracted cannons and now located inland. The one cannon on the left is at Champotón, in front of the Baluarte. The one cannon on the right is located at the Puerta de Tierra in the city of Campeche.