The 71-foot Lady Mary, a scallop boat operating out of the Port of Cape May, sank Tuesday morning about 75 miles southeast of Cape May. Only one of seven crew members was confirmed alive after being in the Atlantic for more than 3 hours. Two more were pulled from the water - one was dead, the other died later - while four were missing at sea. The following is information about the weather and survival conditions at the time of the incident:

What was the weather like at the time the boat sank?

According to the National Weather Service, as of 8 a.m., the ocean temperature was about 44 degrees Fahrenheit. When the accident happened at 5 a.m., the temperature was most likely closer to 41 degrees. However, since the boat was 75 miles out to sea, a jet stream may have raised the ocean temperature by a couple of degrees, according to Greg Heavener, a meteorologist with the National Weather Service in Mount Holly.

A small craft advisory was issued Monday and was in effect until 6 p.m. Tuesday. Heavener said Tuesday morning had rough weather conditions and waves could have been as high as 7 feet at the time of the accident.

What kind of risks could the crew have faced due to the cold temperatures?

With normal body temperature being 98.6 degrees, floating in water that is about 40 degrees for more than three hours could lower the body's core temperature, putting a person at risk of hypothermia.

Since it was early morning, the fishermen may actually have been better off staying in the water initially, according to Dr. Tom Brabson, medical director of the emergency center at AtlantiCare Regional Medical Center, City Campus in Atlantic City. The temperature of the water does not fluctuate as much as the air, so being above the water could have been colder, similar to how a swimmer may feel a chill after getting out of the pool.

As the core temperature decreases, bodily functions such as heart rate and respiratory actions can slow. Once the core body temperature dips below 83 degrees, a person's breathing can stop, which may result in a coma.

What difference does an immersion suit make?

According to the U.S. Coast Guard, all seven crew members were wearing immersion suits, which are designed to protect fishermen in cold water from hypothermia. They are usually worn only when a boat sinks or capsizes.

Immersion suits slow hypothermia by retaining a person's own body heat. They also serve as flotation devices.

The level of protection an immersion suit offers depends on a number of factors, including the temperature of the water and the design of the suit. Age and other medical conditions also factor into their effectiveness.