Five swimming from Plymouth to Provincetown in hopes of creating new marathon swim in Bay State

By Sarah N. Mattero, Globe Correspondent

Hours before dawn today, five people waded into the waters off White Horse Beach in Plymouth and began swimming toward Provincetown, a 20-mile swim they hope will become the prototype for a new marathon swim event.

The group left around 2:40 a.m. and are hoping to end their swim at Herring Cove in Provincetown sometime between 1 p.m. and 2 p.m. today, according to one of the crew helping support the five swimmers.

Many have attempted the Cape Cod swim, but only one has succeeded. Russell Chaffee, of Sayre, Pa., was 41 when he completed the swim in 14 hours and 40 minutes in 1968.

Today’s swimmers are following the rules set up for those who want to swim the English Channel. They are allowed to wear a swimsuit, cap, and goggles but cannot have any assistance during the swim other than an escort boat. Swimmers can be given food at regular intervals, but are not allowed to touch the boat or crew during the swim.

As of 12:20 p.m., the five swimmers were on the final stretch of their journey, said Terence Burke, a member of the support team for the swimmers who include his sister-in-law, Eileen Burke.

Also in the water is Greg O’Connor, an organizer for the Boston Light Swim, an 8-mile course around several of the inner Boston Harbor islands, and Mo Siegel, Janet Harris, and David Barra. O’Connor is from Boston while his colleagues are from New York.

All five have extensive experience in open water and marathon swimming.