Their 32-foot catamaran, the Calypso, was roughly half way to Alameda from Crescent City in Del Norte County, near the Oregon border, when it suddenly capsized in steep waves, a Coast Guard spokesman said.
At about 12:45 p.m., the Coast Guard received an Emergency Position Indicating Radio Beacon, or EPIRB, signal from the Calypso. The signal was the only distress signal received by the Coast Guard from the catamaran.
"If you ever wanted to hear a story about how important it is to have a registered EPIRB on your vessel and a float plan ashore, look no further than this case," Coast Guard spokesman Lt. Todd Vorenkamp said.
The Calypso's crew reported high winds in the early morning hours, with speeds pushing 45 knots, or about 50 mph. Believing their lives were in peril, the crew manually switched on the radio beacon.
Almost immediately after activating the signal, the catamaran capsized, pinning the crew beneath its overturned hull.
Although the crew managed to resurface and cling to the vessel's hull, the three sailors spent more than an hour in the frigid Pacific Ocean waters, according to the Coast Guard.
What saved the Calypso crew was sound emergency planning -- the crew had left a float plan, which is a description of the boat, the passengers and safety equipment aboard, destination and estimated time of arrival.
Using registration information from the beacon to contact the family of the vessel's crew, the Coast Guard learned of the float plan and dispatched a 47-foot motor lifeboat from Fort Bragg and a helicopter from McKinleyville in Humboldt County, which is about 150 miles north of Fort Bragg.
"The float plan allowed us to confirm information about the vessel, create a better plan and expedite our search," said Lt. George Suchanek, a helicopter pilot who responded to the call.
Following the catamaran's radio signal, the helicopter, which arrived eight minutes before the lifeboat, was able to locate the overturned boat, whose hull blended in with the white-capped waves caused by high winds.
As the helicopter hovered over the vessel, rescuers spotted the sailors, lowered a rescue swimmer and hoisted them to safety in the aircraft.
The sailors were transported to a hospital and rescuers noted they were showing signs of hypothermia, according to the Coast Guard.
Mariners are recommended to file float plans with family, friends or a trusted person onshore to keep the Coast Guard informed during emergencies. A good float plan would include a description of the vessel, names of people on board and the intended destination and estimated time of arrival.
The beacon, mounted on the sailboat, can be turned on in an emergency to transmit the GPS position, identity of the vessel and other information to a satellite network.
"Without that piece of electronic gear aboard the Calypso, this would be the story of a maritime disaster, not a story with a happy ending," Vorenkamp said.