WASHINGTON -- The U.S. Coast Guard is moving forward on its long-range plan to build new icebreakers, asking potential builders last week to weigh in on their plans and timeline.

The request shows that the federal government is moving forward on icebreakers despite long-term questions about funding. A single icebreaker is projected to cost about $1 billion.

Alaska's congressional delegation has been pushing for a new Arctic icebreaker for years. The effort got a nudge forward when President Barack Obama visited Alaska in 2015 and pledged to speed up the acquisition process.

And earlier this year, Republican Alaska Sen. Lisa Murkowski scored a $1 billion appropriations amendment to pay for one of the needed new vessels. Whether the funding will materialize in final appropriations is still unknown but she did manage to maneuver the bill language out of the Appropriations Committee.

In a Request for Information issued last week, the Coast Guard asked for input on its plan to contract out studies on building a heavy-duty polar icebreaker in the first quarter of 2017. Those studies would examine in detail the potential costs, schedules, capabilities and technical trade-offs involved in building the massive ships.

The request detailed the Coast Guard's plans to use a single shipyard to build three icebreakers over the next decade.

The U.S. has only two heavy-duty icebreakers. One, the Polar Sea, is unusable and all but scrapped, while the other, the Polar Star, is dedicated to scientific missions in Antarctica. A third icebreaker, the medium-duty Healy, travels in the Arctic mainly as a research ship.

With growing interest in Arctic shipping routes and Russian military activity in the region, Arctic icebreaker advocates have warned that the U.S. could find itself without the necessary equipment to aid troubled vessels in Arctic waters.

In January, Adm. Paul Zukunft, the commandant of the Coast Guard, announced that the military was beginning discussions with ship architects and builders to advance early stages of acquiring a new icebreaker, releasing a draft schedule and set of design requirements with questions for industry.

One lawmaker is concerned about the Coast Guard's contract plans. In a letter to the Coast Guard's vice commandant in charge of acquisitions Wednesday, Rep. Duncan Hunter, R-Calif., who heads the House subcommittee in charge of the Coast Guard, lamented that it appeared the military is not considering a "block buy," consolidating the three icebreakers under a single contract.

If that is the case, Hunter said, he is "very much concerned about the lost opportunity and additional costs that are likely to be incurred over time." Purchasing three icebreakers in a single contract could save $100 million and speed the process, Hunter said.