The dark, orange sun sets slowly over the calm waters of the Pacific Ocean just off the coast of Oahu. The lone fisherman looks over his catch for the day and decides to head back in. He goes to start his 80-foot fishing vessel, but the engines will not turn. He opens the bilges, a compartment within the boat's hull, and realizes they've filled with water. He looks at his small hand pump and knows right away it will not suffice with the significant amount of water that is already in the bilge. He rushes to his radio and makes the call a boat captain prays he never has to make.

Some mariners may not realize what goes on behind the scenes when they make a call for help. The men and women of the Coast Guard want boaters to know, however, their "Coasties" will be there when called upon. There are vital systems the service maintains to ensure those in need receive fast and timely assistance.

That's where Coast Guard communications stations come in to play and here's how they work:

As soon as a mariner's radio is keyed on the south shore of Oahu, a signal is immediately transmitted to Coast Guard Communication Station Wahiawa, which is the receiver station for calls between Diamond Head and Kaena Point. Five Coast Guard electronics technicians work at this station and ensure all communications systems are working properly.

"CommSta Wahiawa houses the main tower that receives all information being passed," said Petty Officer 2nd Class Brian Burke, an electronics technician stationed at Wahiawa.

This information can either be voice, such as a verbal mayday call, or data, such as the signal sent by an Electronic Positioning Indicating Radio Beacon (EPIRB).

The tower then processes the information, such as a boat's position, people on board, type of vessel and weather conditions, and sends it via cable lines to Communications Station Waianae, the transmitter station, said Burke.

Communications Station Waianae's transmitters, maintained by 11 Coast Guard electronics technicians, will then send the distress signal to one or more towers; within seconds, a reply signal will reach the original source after it goes through a receiver in Wahiawa and one in California, said Petty Officer 2nd Class Randall Painter, an electronics technician at the Waianae station.

Painter also said all communications are recorded.

There are more than 20 towers on Oahu and more than 30 towers throughout the Hawaiian Islands the Coast Guard uses to monitor mariners' calls. The towers utilize Very High Frequency (VHF) radio frequency, a frequency commonly used for marine communication.

The parent station for all communications in Hawaii and most of the Pacific is the Communications Area Master Station Pacific (CAMSPAC), located in Petaluma, Calif. The technicians at that station are responsible for most calls in the Pacific and pick up signals from the South Pacific to Alaska.

Maintenance of Hawaii's towers is critical for Coast Guard operations and the safety of mariners at sea.

The Coast Guard recommends all mariners practice safe boating and have life-saving equipment onboard, such as Coast Guard-approved life jackets, a VHF radio and flares.

For more information, please visit www.uscgboating.org/.