RYE — The EDALHAB, a 21-ton undersea habitat built in 1968 by six undergraduate engineering students at the University of New Hampshire, doesn’t look like an innovative research tool given today’s standards.
But in those days it was considered groundbreaking.
On Sunday, more than three-dozen gathered at the Seacoast Science Center to celebrate the research done off the Isles of Shoals 50 years ago where the underwater capsule is on permanent display.
The 8-foot wide and 12-foot long habitat was built from a tank and used for several years as an undergraduate laboratory. Up to four divers could live and work 30 to 50 feet beneath the water’s surface, for up to four days.
“It looks big on the outside, it is very small on the inside,” said Tom Glennon, who did research out of the habitat in 1971 as a senior at UNH.
Once completed in 1968, Lake Winnepesaukee became the spot used for trials at the depth of 50 feet.
The habitat allowed 20-minute dives every two hours without having to decompress, known as saturation diving. Any dive over 33 feet requires decompression.
The EDALHAB received support from Woods Hole Oceanographic Institution’s catamaran, Lulu, and became the nation’s first mobile habitat and laboratory system.
On the 1971 “mission” off the Isles of Shoals, Glennon, along with Erick Sawtelle, did research on dungeness crab farming located about 45 feet below the surface. Engineer Mark Hertel was also in the habitat for four days. Equipment was used to monitor the heart, respiration and oxygen consumption rates, according to a New Hampshire Sunday News article dated June 13, 1971.
The study on crabs from the West Coast was to see how they would interact with native species such as lobsters. The crabs, however, were never introduced to the water.
Sawtelle remembers not getting much sleep because of the hectic schedule and the conditions inside.
“It was 100% humidity all the time,” he recalled. “Nothing ever dried in there.”
The habitat was built using scrap, including two 275-gallon oil drums and railroad wheels.
The three needed to spend 11 hours in a decompression chamber after the mission, so they would not to get “the bends” or decompression sickness from exposure to increased pressure.
Glennon said the reunion was supposed to happen last year, but was postponed because of the COVID-19 pandemic.
“We just went full boar into this thing,” he said. “We trusted this and that it would not leak and the engineers were going to keep us alive. They just pumped in compressed air from the Lulu.”
Larry Harris, a retired UNH biology professor, helped oversee the project.
“It was very groundbreaking,” he said. “There had only been two U.S. habitat efforts up until that point.”
For several years, the EDALHAB was used by federal agencies in experiments off the Isles of Shoals, as well as the east coast of Florida, according to Union Leader archives.
The program helped launch the student project course for ocean engineering majors at UNH.
“It was a significant contribution to marine research,” Sawtelle said.
Much of the research is done with remote vessels nowadays, Glennon said.
“The period of underwater habitats has come and gone,” he said. “Everything is remotely operated. You don’t need a team on the ocean floor doing research or even oil exploration.”
In all, about 17 people involved in the project joined in on Sunday’s reunion.
Sawtelle said efforts are underway to restore and relocate the capsule. He joked about posting the space on Airbnb for overnight stays.
“We can have a sea Airbnb,” he joked.