With the delivery of the planned eight national security cutters (NSCs) to the U.S. Coast Guard almost half complete, the service is beginning to realize the full potential the platform brings to the table.

Three of the 418-foot Legend-class cutters have already been delivered to the service. The keel has been laid for the fourth, the Alexander Hamilton, and commissioning is expected in 2014.

Fabrication for the fifth hull has begun and a contract for the sixth has been let. Details are still being worked for the final two with respect to funding and build scheduling, though officials say they’re still in the service’s plans.

The first ship in the class, the CGC Bertholf, is nearing five years in commission. Bertholf is homeported in Alameda, Calif., as are all the NSCs so far.

This past year, the Bertholf completed a 144-day patrol that stretched the cutter and crew to new levels. It performed a full range of missions, from national security defense operations on a multinational fleet level to classic Coast Guard missions.

That’s because the bulk of the Bertholf’s patrol was spent participating in two major exercises, initially the multinational Rim of the Pacific (RIMPAC) Exercise, based out of Hawaii, followed by the Coast Guard’s Alaska-based Operation Arctic Shield, a multi-U.S. agency exercise in and around the state of Alaska.

As part of Arctic Shield, the Bertholf conducted extensive operations above the Arctic Circle, a first for any national security cutter and one where the NSC and the crew marked a significant milestone in the maturation of the national security cutter’s capabilities as a crucial asset to the Coast Guard and nation.

The service’s approach to its massive job of keeping the U.S. coastline and maritime regions safe for people and commerce is called “security in depth.” It’s a layered functioning concept with three basic operational areas of focus: inland, coastal, and offshore.

‘‘The national security cutter is effective in all three,” said Capt. Thomas E. Crabbs, Bertholf’s commanding officer. ‘‘But with superior seakeeping, extraordinary endurance, the capacity to project three over-the-horizon boats, and carry two helicopters, it’s really the nation’s most effective security asset in the offshore operations space.’’

Those same capabilities are also what make the NSC highly capable in the coastal operations space, Crabbs said. With a draft of 22 feet, the cutter has the ability to work close in to shore. That proximity to shoreline provides enhanced presence for not only the Coast Guard, but any service or agency involved in the ship’s operations as well.

Even operating in inland waterways, he said, the NSC is outfitted with a chemical, radiological, and biological defense capability that allows the ship and crew to remain on scene and operate in response to multiple types of weapons of mass destruction scenarios. The system keeps a slightly higher air pressure inside the ship, keeping contaminants out.

Regardless of where it is deployed, key to the NSC’s success while operating alone or with other ships is the command and control system, which raises the awareness of the cutter’s commander and crew because of its ability to operate at the highest levels of classifications, able to reach out to the highest levels of government.