In its 71 years in business, Collins & Jewell Co. Inc. has operated at three sites in eastern Connecticut, moving twice in search of more space. The supplier for Electric Boat is now considering expanding at its Bozrah location to keep up with rising U.S. military demand for submarines.

Electric Boat, the Groton-based subsidiary of General Dynamics Corp., is ramping up to build two subs a year, with the start of design of the Columbia-class ballistic missile submarine. More than 5,000 firms in the U.S., including nearly 450 in Connecticut, supply parts.

"We've really been growing like gangbusters," said Chris Jewell, chief financial officer. "Electric Boat, it's unbelievable."

Collins & Jewell's workforce of 70 is up from 50 three years ago — a painter and an entry-level worker were hired recently — and more than a dozen jobs could be created in the next year, Jewell said. A third shift also could be added, he said.

In Connecticut, where the number of low-paid jobs are increasing faster than work with higher compensation, defense industry manufacturing jobs are prized for their pay. For example, Collins & Jewell pays $13 an hour for entry-level jobs, rising to as much as $35 an hour for skilled labor, Jewell said.

The privately held Bozrah manufacturer, with its 35-foot high ceilings and a cavernous factory floor, is well-suited for the manufacture of massive structures used by Electric Boat workers to build submarines. Other equipment at Collins & Jewell include heavy rigging equipment that can hoist up to 100,000 pounds.

"Everything we've built for the Virginia class they'll need for the Columbia," Jewell said. "That's great for us."

As suppliers such as Collins & Jewell benefit from an increased workload, the manufacturer of the submarines — among the most complicated machines — is juggling demands for more workers and an increase in suppliers.

Rep. Joe Courtney, D-2nd District, said a recent Washington, D.C., gathering of submarine contractors drew the biggest crowd ever, with some companies turned away. Electric Boat and its partner, Huntington Ingalls-Newport News Shipbuilding in Virginia, rely more on outside suppliers than on work done in their shipyards that was typical of the Cold War era, said Courtney, whose district includes EB's Groton site.

That's shifting attention to thousands of companies supplying parts for Electric Boat to ensure availability of contractors, workers and materials.

William Lennon, vice president of the Columbia program at Electric Boat, said its developing plans to accommodate increased manufacturing and assembly, such as new facilities for construction, timing of the various stages of work and the mix of work skills needed to support construction.

EB President Jeffrey Geiger told local officials and others in January that the submarine maker plans to spend $1.5 billion in Rhode Island and Connecticut to increase assembly and other space in the coming years.

EB is looking to expand its base of suppliers by finding companies that can apply their commercial products to submarine manufacturing, Lennon said.

"We look at people who do the commercial equivalent of making a mousetrap or could expand into the marketplace," he said.

Each Virginia Class submarine costs about $2.7 billion to build, according to the Congressional Research Service. It contains 1 million or more parts, including an antenna and receiver to detect radar, cameras that replaced optical periscopes, air turbine pumps to propel torpedoes, air conditioning, seawater desalinization equipment and components for electrical systems and power generators.

Electric Boat will invest in companies to help the businesses meet qualifications such as welding, he said. And compliance with cybersecurity measures also is a "big piece" of the effort to sign up new suppliers, Courtney said.

The No. 1 issue, however, is a workforce ready to fill jobs at Electric Boat, said Courtney, a member of the House Armed Services Committee. A jobs pipeline linking EB with vocational schools, community colleges and training and recruitment centers helps match jobs with employees, and he said funding is being sought for apprenticeships for small companies.

Electric Boat is working with Connecticut and Rhode Island education and labor officials on workforce training "to make sure they understand what our demands will be," Lennon said.

EB now has about 14,800 employees, hired nearly 1,600 last year and is projecting a workforce of about 18,000 in the next 15 years in Groton and Quonset Point, R.I. Not all hiring brings in new workers, but replaces those who quit or retire.

Keith Macdowall, vice president for sales at Prime Technology, a North Branford manufacturer of devices that measure temperature, pressure and other conditions in submarines, said suppliers must coordinate purchasing of materials with funding from the submarine maker.

"Government spending is up and down," he said. "You never know when money is going to be spent."

Mark S. LeClair, a professor of economics at Fairfield University, said manufacturing jobs producing submarine parts are among the most valuable in Connecticut, comparable to workers who produce Sikorsky helicopters. The impact of increased hiring on the state's economy "would be substantial," he said.

A submarine building boom also would boost the value of the submarine base in Groton, protecting it from a possible shutdown, LeClair said. "That's a really big deal," he said.

Then-Gov. M. Jodi Rell and Connecticut's congressional delegation successfully overturned a federal recommendation in 2005 that the base be closed.

Driving the increase in jobs and workers is a shift in U.S. military strategy to counter moves by China, Iran and Russia. The U.S. Navy last year called for a nearly 15 percent increase in the number of ships, to 355, with an increase of 18 attack submarines, to 66.

Robert Mongell, founder of Micro Precision, a South Windham manufacturer of hydraulic systems for submarines, said Connecticut's sub industry has risen and fallen in response to shifts in defense policy, changes in congressional spending, weaknesses or strengths in the economy and the availability of capital.

"It's very hard when you have periods of boom and periods of bust to maintain a viable business unit," he said.

The collapse of the Soviet Union in 1991 and a recession at the same time hit Connecticut manufacturers hard, Mongell said.

"For defense contractors in Connecticut and elsewhere, the amount of work just plummeted," he said. "You couldn't diversify because the economy was so weak."

Right now, however, Collins & Jewell and other manufacturers are anticipating strong business for years to come. "It's a good future for us," Chris Jewell said.