You’ve seen those classic rowing shells – Oxford students on the Thames, Harvard squads on the Charles. But now shells have migrated to the coast of Maine, evolving – along the way – into a fairly seaworthy craft a novice can handle.

Leading the transition are two southern Maine companies located in hailing distance of each other, and related by prior ownership. One is Echo Rowing, a new firm which draws on personal experience and aboriginal kayak design to craft a one-person recreational rowing shell that is fast and easy to rig. The other is the widely-known Alden Rowing Shell firm, formerly owned by the same family that is now building Echo shells, the competition.

Some 25,000 Alden shells have been sold in the past 33 years, while Echo, a new company with its roots in Alden, has sold closer to 110 shells. Based in Eliot, Alden has 13 models, of which four are classified as recreational, the others competitive and traditional. Ed Jarvis is the latest owner of Alden, having owned it for three and a half years.

The Echo company, also based in Eliot with a boathouse at Kittery Point, builds the 18-foot fiberglass, 48-pound Echo; and now the 58-pound Islander, a model with closed cockpit, two hatches suitable for carrying a week’s camping gear. You can race these shells, which are beamier than traditional competitive shells used on flat water, but the emphasis is on simply rowing for pleasure, or short, island-hopping cruises.

The Echo and Islander feature fold-away rigging for the oars, a system that leaves fewer parts and fewer things to do to prepare for a row.

Doug Martin designed the first Echo, and works in partnership with sister Lorna Martin Perry and her husband, Ted, who started East/West Custom Boats in Eliot in 1978. Doug and Lorna are the children of Arthur Martin, who in the 1960s designed a seagoing ocean shell for his own use around home in Cohasset, Massa-chusetts. Even before that he built kayaks with his children, in the 1950s.

The father worked for John Alden Associates, and the owner of that yacht company, the late Neil Tillotson, gave Martin permission to use the famous Alden name.

When Arthur Martin rowed around in his ocean shell, people stared, and asked where they could get one. In 1971, Martin moved his family and his shell business to Kittery, where he built hundreds of oceangoing shells.

Meanwhile, Doug Martin designed and built small wooden sail, oar and power boats at Strawberry Banke, a historic area of Portsmouth across the Piscataqua River from Kittery. One of his designs was featured on the cover of Woodenboat magazine. After his father died, the family sold the Alden ocean shell business to Oakes Ames, who built it up and finally sold to Jarvis.

For a couple of decades, Ted Perry built the Alden shells in his Eliot shop. Today, Alden shells are built elsewhere in New England and Canada, while Echo shells are built in town. The rivalry between the neighboring firms is for the most part friendly. Debbie Arenberg, a spokeswoman for Alden, said her first babysitter was Ted’s wife, Lorna.

Over the years, even after his father’s business was sold, Doug Martin stayed interested in sculling. “I had a lot of ideas I’d been working on, and Ted had some space,” he said. In May, Doug’s daughter Anna got an 18th birthday-graduation present of an Echo shell, which she proudly demonstrated on Chauncy Creek, rowing into the fierce chop of the river.

Doug Martin is pleased with his folding rigging design. “I thought it was sort of a gimmick but it’s proved to be much more useful,” he said. He sees recreational rowing shells as akin to mountain biking, and believes “the Echo falls into a distinct little niche.” Unlike traditional shells, his design features a square stern and a bow designed to ride the waves, not nose into them. The bow design comes from a kayak he saw with a bow like a hand with palm up.

Arenberg said she admires Martin’s folding rigging, but in the interests of weight, Alden shells have detachable rowing rigging. Alden shells range from 16 to 26 feet, the latter being the traditional length of a single scull. Most Alden models are fiberglass, a few are carbon fiber, and some Alden oars are carbon instead of wood or aluminum.

One tradition that continues is a 7.2 mile Alden shell race from Portsmouth to Isle of Shoals. Alden also equips shells for blind, deaf and other disabled rowers – including amputees – who compete in an annual championship.

Doug Martin likes to combine technical advances with ancient boatbuilding wisdom. In designing boats, he said, “there is nothing completely original. Things have their antecedents. Martin has studied Inuit kayaks and badarkas. He has built a 35-foot Hawaiian canoe with outriggers and carved decorative bows that Hawaiians say is more traditional than some of their own watercraft.

Recreational rowing shells will be exhibited at the Maine Boats & Harbors show in Rockland, Aug. 13-15; and at the third annual Belfast Small Boat Regatta, Aug. 14.

Alden Rowing and Medomak Retreat Center, a summer camp in Washington, are sponsoring coached rowing with lakeside accommodations, June 24-30.

For information on Alden, the web address is rowalden.com. To contact Echo Rowing, the web site is echorowing.com.