On Aug. 27, researchers from the Naval Submarine Medical Research Laboratory (NSMRL) from Groton, Conn., used the Doriot Climatic Chambers at the U.S. Army Soldier Systems Center (SSC) here, to begin an evaluation of two different designs of submarine escape immersion equipment (SEIE) suits.
"They are trying to simulate an emergency evacuation from a disabled submarine and waiting for rescue," said Josh Bulotsky, electrical engineer, SSC.
Participating in the study are four volunteer Navy divers, similar to SSC's Human Research Volunteers. The volunteers are divided into groups of two; each group is in the SEIE in an inflatable pool within the Chambers.
Lt. Jon Vanderweele, undersea medical officer, NSMRL, said the Navy is looking at two competing designs of SEIE to possibly replace the current generation of SEIE suits aboard submarines. Both consist of a dry suit with inflatable hood and air pockets that also have an inflatable raft attached.
"Rescue is always preferable to escape, but if the crew on a disabled submarine is forced to escape by swimming out the escape trunk, this equipment is designed to keep them afloat on the surface until they are picked up. We want to evaluate its ability to keep them warm in an arctic sea environment," Vanderweele said. "After escaping, the submariners may end up scattered over a large area and they may be waiting a day or two before rescue. We want to prevent hypothermia while they are waiting."
The idea is to look at the equipment to evaluate the two different designs to see the pros and cons of each, including which design provides the best thermal protection.
Speaking about the conditions of the test, Bulotsky said, "The chambers are down to 35 degrees [F] with a 15 mile-per-hour wind constantly blowing."
Vanderweele pointed out that the water in the pools is also chilled to 37 degrees F.
"We periodically pour water on top [of the volunteers] to simulate waves or rain," he continued. "We want to see if heat gets pulled away from the SEIE suit."
Eleven different sensors monitor the volunteers' core and skin temperatures. Although the idea was to have the volunteers sit in the pools for 24 hours straight, the divers needed to stop this first test after approximately eleven and one-half hours. Even after about three and one-half hours, the divers were starting to say their hands and feet were beginning to get cold.
Vanderweele stated that the goal is to have five iterations of the test.
We will take the data and evaluate it to see if one design is better than the other or if there is some combination that might be best, he said. For instance, based on the hands and feet comment, maybe there is a need for better gloves or booties.
The Combat Feeding Directorate (CFD), after learning about the test, also provided some rations for evaluation. They provided shortbread bars, a previously approved ration component, and the volunteers are going to evaluate the packaging and ease of use in a wet, cramped environment.
Vicki Loveridge, CFD, said the bars are a current component of the Food Packet Survival, General Purpose and have a proven shelf life beyond the current requirement of five years. The Navy has expressed a need for a product with a seven-year shelf life, she said. The participants will eat one shortbread bar every six hours during the study, and after testing, divers will be asked to complete a brief questionnaire to gather information on product acceptability.
Bulotsky said CFD was "thrilled" to have the opportunity for the divers to evaluate the rations during the test.
For upcoming iterations of the testing, Vanderweele is working with the CFD to see about the possibility of evaluating reverse osmosis water purification systems in order to convert sea water into potable water for inclusion into the SEIE system. CFD will be providing NSMRL some information on these types of systems.
Both Bulotsky and Vanderweele agree that this has been a good collaboration between the Army and the Navy.
Vanderweele said that doing testing with manikin simulations is not the same as human volunteers, and although the original thought was to do this testing at sea, the Doriot Climatic Chambers provides much more controlled test conditions and is safer for the volunteers.
"The applications for the Chambers are endless," said Bulotsky.