PORTLAND — The classic canvas tote has symbolized Maine for decades. But in the last few years, another bag is starting to dominate.

Sea Bags, made of recycled sail and nautical line, are crafted in Portland by a team of seamstresses and designers. The popular accessory, sold by J. Crew, Tommy Bahama and Sperry Top-Sider, is suddenly everywhere.

To keep up with demand for these satchels, branded with original sail markings as well as lobster claws, anchors and assorted nautical imprints, owners Hannah Kubiak and Beth Shissler are charting a course for success.

This fall, the company is tripling its manufacturing footprint and expects to increase hiring by 20 percent within the next year. Above their headquarters on Custom House Wharf, they have added 2,700 square feet of space for production and are working feverishly on their spring 2014 line.

“The goal is to keep our jobs here in Maine, to grow our company in Maine and to do it sustainability,” said Shissler, who grew up in Topsham and left a successful career in semiconductor sales to join Sea Bags in 2006.

With 30 employees and a projection to expand to almost 50 in the near future, they are well on their way.

“This will allow us significant growth,” said Shissler, who was Sea Bags’ first wholesale customer years ago. “We are looking at extensive but sustainable growth.”

Last year Sea Bags produced and sold 42,000 items — from totes to wine bags to iPad covers. The most popular tote, emblazoned with a navy blue anchor, retails for $130. They are fashioned out of old sails made of wax canvas, cotton canvas, polyester and high-tech Kevlar and mylar.

In the early days, people donated sails, but now that Kubiak’s brainchild has launched scores of knockoffs, they are hard to come by.

“In the beginning, people said, ‘Oh look at these girls, they are struggling. I’ve got some old sails, I’ll just drop them off,’” said Kubiak. “Those days are long gone.”

Now they trade bags for sails and employ a full-time sail acquisition manager who scours the Eastern Seaboard, West Coast and abroad for material.

With the new space, Sea Bags will enlarge its shipping department, retail space and open up overseas channels.

In the 14 years the company has been in business, its furthest shipment was Saudi Arabia. This week, Shissler was working on setting up a distribution chain in Australia.

Despite their success (or perhaps because of it), Kubiak and Shissler say keeping their product made in Maine is top priority. Sea Bags hires local stitchers, most of whom sew in the wharf retail shop for all to see, while a few work from home.

“We’ve become somewhat of a destination. When people come to Maine, they’ll come in and say, ‘I want a bag with the number eight on it and we’ll say, ‘come back in two hours,’” said Shissler, who is passionate about cut-and-sew coming back to the U.S.

“We’ve lost an amazing skill set in the state of Maine, and these are all highly educated seamstresses. I believe there is a lot more of this that can happen in Maine,” said Shissler during a recent tour of the production floor click-clacking with activity. “The textile industry goes way back in Maine and so much of the business has gone offshore.”

Sea Bags’ determination to stay on the working waterfront is a choice. As is using U.S. materials — from North Carolina thread to rope from Massachusetts.

Shissler said it would be more efficient to move from the creaky wharf to a true manufacturing space but the authenticity that consumers crave would be lost.

At travel boutique Daytrip Society in Kennebunkport, Sea Bags is a top seller year after year because of the Maine allure. “People come back multiple times and say, ‘This is the gift I give, this is the Maine gift,’” said co-owner Jessica Jenkins. “They have a reputation now.”

And a longevity that parallels L.L. Bean but “has more cache because of the recycled sails. It’s crossed over from being the beach bag for the local Mainers to a trend where the college girl wants to bring it back to school,” she said. “It’s the ocean, it’s the sea, it’s sailing and you get to carry it. It’s the whole romance of Maine.”

The company that was born and branded on the wharf has no plans to end that romance. And that’s good for the economy.

Locally owned and operated businesses typically keep their dollars here, says Jeff Levine, Portland’s director of planning and urban development.

“They will hire locally, and the money doesn’t tend to leave the city,” he said.

While food manufacturing is thriving in Portland, traditional manufacturers, such as those stitching bags by hand, “tend to want a big facility,” said Levine. “We are always happy when a local business is successful and expands. It shows that money is being re-circulated.”

Kubiak, who started Sea Bags in a cramped space with two sewing machines, marvels at her growth. In 1999, she was selling 100 bags a year and didn’t know how to scale her business.

Her reasoning was, “why should I make more bags and get less money for them?” she recalled.

Shissler, whose mother ran a gift shop on Isle au Haut, was her first wholesale customer.

Armed with an MBA from Boston University, Shissler knew Sea Bags was the right product at the right time.

She took Kubiak out to lunch and impressed her with her business prowess.

“She was the missing ingredient to keep Sea Bags on a straight and narrow path in order to build. I was at a certain position where I couldn’t take it any farther,” said Kubiak, who started the business at 25. “I didn’t have the drive to do it or the experience.”

But, according to Shissler, she had “talent with a good idea and good product.”

Sea Bags’ wall of fame illustrates their success — a red sail duffle made for Puma, the first bag sold to J. Crew; the bag featured in O, The Oprah Magazine; the women’s Olympic sailing team satchel.

“We’ve worked hard to take the cyclicality out of our business,” said Shissler. “Before we were considered a summertime product and now we work to make sure we are busy all year long.”

Besides the accolades and famous people clutching Sea Bags from The Hamptons to Harpswell, success for these women means keeping those machines humming.

“We’ve never really measured our success in units.” said Shissler. “Success for us is making payroll every week.”