Oil and gas aren’t the only treasures oil companies discover in the Gulf of Mexico.
Over the years a plethora of shipwrecks have been uncovered there as a result of oil and gas activities -- and as companies have increasingly moved into deeper waters some extraordinary wrecks have been found lying thousands of feet down.
All the ships have a fascinating story to tell, but in one case a wreck has important historical significance for the United States.
"The 1966 National Historic Preservation Act requires every federal agency to consider the affect of any undertaking -- such as permits -- on the cultural and archeological resources of the United States," said archeologist Jack Irion, supervisor of the Minerals Management Services’ social sciences unit.
This is more common on land, but in the case of the outer continental shelf, Irion said it applies to two things:
- Drowned prehistoric sites dating back to when the shelf was dry land thousands of years ago.
"This requirement has been incorporated into MMS regulations governing leasing," Irion said. "However, since the Gulf of Mexico is such a big area and shipwrecks certainly are not found everywhere, we have conducted a number of studies based on historical records and old charts and maps to determine the areas where wrecks are most likely to occur."
Based on that model, oil companies are required to conduct remote sensing surveys over leases in the areas with the highest potential for shipwrecks.
'Tremendous Amount of Data'
The move into deeper waters has made this process considerably more difficult, Irion said.
"Many of the deepwater wrecks have been in areas that were so far offshore we really didn’t have good records on where these ships might have sunk," he said. "Plus, the older the ship the less precise the navigational technology was at the time, which confounds any attempt to nail down precise locations of wrecks."
Even World War II era navigational systems were such that positions of reported wrecks can be off by quite a bit within the standards of navigational accuracy.
"As a result, we have been forced to expand the lease areas requiring remote sensing surveys," he said. "In more than a few cases just recently shipwrecks have been found in places we had no idea would yield a wreck."
While the remote sensing surveys certainly cost oil companies time and money, they are necessary. Some companies have attempted to meet the lease stipulation with 3-D seismic surveys, but Irion said that these data are not designed to image anomalies on the seafloor.
"In areas where there are known shipwrecks, they have not shown up on 3-D seismic," he said. "The resolution simply is not good enough for these instruments to distinguish even large shipwrecks on the seafloor."
That may be why most of the deepwater wrecks have been found during pipeline surveys that require shallow hazard remote sensing technology.
"The use of autonomous underwater vehicles and remotely operated vehicles have been a tremendous leap forward in our ability to find these wrecks," he added.
Traditionally companies used a deep tow system for pipeline surveys. This entailed dragging the side-scan profiler on cables that in deepwater can be five times the water depth.
"It could take five miles of cable just to tow the sensor, which means making a turn is a laborious process that can take hours," he said. "Plus, a second boat is necessary to keep track of where the sensor is on the seafloor."
There is also the constant danger that the sensor will get snagged or the chain weighing the sensor down will cause damage on the seafloor.
"The AUV’s are more expensive to deploy in terms of day rates, but overall they can be more cost effective," he said. "We are hopeful more companies will bring this technology into the Gulf of Mexico. Aside from the potential to locate shipwrecks, we glean a tremendous amount of data from these surveys."
Irion said the Viosca Knoll and Mississippi Canyon areas in the deep water have yielded the most shipwrecks, because these areas are in major shipping lanes coming into New Orleans.
Many of the shipwrecks are casualties of the U-boat war in the Gulf of Mexico during World War II, when numerous tankers and freighters were sunk by German U-boats.
In fact, in May 2001, while conducting a routine pipeline survey for BP and Shell, C&C Technologies found the only U-boat sunk in the Gulf -- solving a 59-year old mystery and ending decades of futile searching.
The submarine lies in 5,000 feet of water, 45 miles off the mouth of the Mississippi River, within a mile of her last victim, the passenger ship SS Robert E. Lee. Lafayette, La.-based C&C Technologies made the discovery on the Gulf of Mexico maiden voyage for its newly developed unmanned mini-submarine remote sensing tool.
"This has to be one of the most important discoveries in terms of history in the Gulf area," Irion said. "Very few people today are aware that the Germans were able to penetrate the Gulf of Mexico. People tend to think of World War II being fought in far away places and don’t know there was action literally in site of our own coastline.
"It gives you pause to realize that the terrorist attacks on 9/11 were not the first time we have been attacked on our own shores."
In May 1942 a ship was sunk in the Gulf almost every day by the U-boats, accounting for the lion’s share of the 56 total ships sunk.
"The Germans had devised a plan to raid our coasts with U-boats as soon as we joined the war," he said. "The effort started in the Atlantic with the goal of halting shipments of materials to Britain."
If they had been successful the outcome of the war could have been very different.
"However, Hitler had a distrust of the navy and approved only half of the number of U-boats his admirals had requested," he continued. "Even so, they achieved some success because the United States were caught completely unprepared. We had no defense against the U-boats or an understanding of how it would impact us. We had not adopted the tactics the British had instituted like sending ships in convoys protected by Navy destroyers.
"Plus, people onshore were unaware of the situation," he said, "and at night the city lights would be ablaze, backlighting the ships as they sailed out of the harbors. They were sitting ducks."
Two-for-the-Price of One
After operating in the Atlantic, the U-boat efforts shifted to the Gulf of Mexico, where the primary targets were tankers carrying gasoline, fuel and other products that were critical to the war effort in Europe.
Irion said it was estimated that the loss of every tanker was equivalent to a division of men, so this U-boat operation had a major impact. In fact, the first interstate pipeline was built from Texas to New Jersey to lessen the reliance on ship transport.
During 1942 and 1943 a fleet of over 20 German U-boats cruised the Gulf. After their initial devastating successes in May 1942, merchant vessels began cruising with armed convoys and became a more difficult target. Oil industry remote sensing surveys have uncovered several of the victims of the U-boats, including the Heredia, a United Fruit Company freighter, the oil tanker Sheherezade, and the Gulfpenn, which carried 90,000 barrels of fuel oil.
However, the crowning discovery was the SS Robert E. Lee and the U-166. Irion said the Robert E. Lee was hit off the mouth of the Mississippi and its Navy escort, the sub-chaser PC-566, immediately began dropping depth charges.
"Although the Navy was fairly convinced they had sunk the U-boat, a couple of days later a U-boat was spotted 130 miles away by a Coast Guard amphibious aircraft and everyone assumed it was the same submarine," he said. "Nobody realized there were two U-boats operating simultaneously in the same general area."
The second U-boat 171spotted by the Coast Guard was sunk later during the war while approaching the coast of France. The captain and several crew members survived and the captain recounted his mission in the Gulf of Mexico and actually indicated he had been spotted by "a flying boat," which dropped a torpedo but missed.
"So, there is documentation that this was the submarine the Coast Guard had spotted," Irion said.
C&C Technologies has received a grant from NOAA’s ocean exploration office and they are planning to go back to the wreck site this October to do follow-up research, particularly to assess the preservation potential and to map the site and determine more accurately how the submarine sank.
The company plans a live Web broadcast as well as other education activities in conjunction with its work, he said.
Of course, the U-boat is just one of several recent deepwater shipwreck discoveries. Recent discoveries date back to the early 1800s, complete with fascinating histories.
• In February 2001 ExxonMobil notified the MMS of a shipwreck discovery during pipeline construction in over 2,600 feet of water at its Mica project.
Irion said the firm had conducted a remote sensing survey over the pipeline route, but the small wreck was hidden in a blind spot directly beneath the sensors. When the firm came back over the route with an ROV to check the pipe they found the 200-year old shipwreck.
ExxonMobil sponsored a preliminary expedition to photograph the site, which is about 30 miles off the mouth of the Mississippi River. The lower part of the shipwreck is almost completely intact and sitting upright on the seafloor.
The ship is about 60 feet long and its wooden hull is covered with thin copper sheets, a method used by shipbuilders from the end of the 1700s to the mid-1800s to protect ships from wood-eating marine organisms.
This wreck is intriguing because copper sheathing was quite expensive and it was unusual to find it on a small merchant vessel. The ship is just 65 feet long.
"It is proving difficult to find any historical records on the Mica wreck," Irion said. "We have not been able to uncover why it was in the Gulf, where it was going or where it had been. We do know the two-masted sailing ship dates to the early part of the 1800s, between 1815 and 1820."
There was some evidence that the ship had burned. Planks recovered from the wreck site clearly were charred and have been identified as American white pine, which is native to the Atlantic coast north of Virginia. Based on that information it is believed the ship was built in the northeastern part of the United States.
Texas A&M entered into a cooperative agreement with the MMS to conduct an archeological investigation of the shipwreck. A&M researchers obtained detailed side scan images and videotape of the wreck from a U.S. Navy deep research submersible.
• While working on the Mica shipwreck, Texas A&M researchers were interested in studying additional deepwater wrecks and contacted the MMS for potential sites. University researchers teamed up with Deep Marine Technology of Houston for archeological studies of these wrecks.
"We suggested they check out a target imaged by side scan technology in the 1980s but had never been confirmed," he said. "It was definitely ship shaped and pointed at both ends, indicating some type of sailing vessel."
Texas A&M and Deep Marine Technology used an ROV to investigate the site and uncovered the Western Empire, a 190-foot long wooden-hull sailing ship that sunk in 1876 in 1,300 feet of water not far from the Mica site.
"Coincidentally, we had just taken delivery of a new computerized Geographic Information System database of shipwrecks in the Gulf that had been developed for MMS," Irion said. "Using this tool, we pulled up the coordinates for the site to determine what historical data might exist on the location and found that within a 10 mile circle of the site a British merchant ship called the Western Empire had been lost."
The ship was built in 1862 in Canada and initially was involved in trade to India and Australia. On its last voyage it had picked up timber from Louisiana.
"It is fascinating to research these wrecks," he said. "For instance, we found records that indicated at one point during a voyage to India there had been a mutiny on board the Western Empire, complete with gun battle."
• Another recent discovery was made by BP and C&C Technologies in 4,000 feet of water in the Viosca Knoll area. The wreck of the steam yacht Anona was identified using a combination of remote sensing instruments in C&C’s AUV and cameras mounted on a ROV.
The Anona was a 117-foot long, steel-hulled, propeller driven steam yacht built in 1904 for Detroit industrialist Theodore DeLong Buhl, who owned it until his death in 1917, when it was passed to his wife Elizabeth, the daughter of Hiram Walker, founder of Canadian Club Whiskey Distillery.
Elizabeth owned the vessel until 1924, when she sold it to a Canadian buyer. Over the years the Anona passed to several owners until it eventually became the property of the Pan-American Banana Producers Association of Montreal in 1943.
"After starting life as an elegant luxury yacht , the Anona met a rather ignominious end in 1944 when it sand carrying potatoes to the British West Indies," he said.
The wreck of the Anona is in an excellent state of preservation, sitting upright on its keel.
"Interestingly, we have been able to obtain the entire set of original building plans for the ship from the MIT library where they have been housed," Irioin said.
"A nice byproduct of our duties to regulate the offshore oil and gas industry is that we can tell stories such as these," he added. "The oil companies have been more than willing to shoulder the responsibility of preserving historic shipwrecks. Many firms have come forward voluntarily to help us research and study these wrecks.
"History is something most people find fascinating, and shipwrecks have always been good stories."