Newcastle’s Herbert Smith added sit-ups to his daily exercise regimen a couple of years ago. Last summer, Smith, 75, was glad he did — for an unexpected reason.

In an 80-year-old, canvas-covered, square stern canoe with an outboard motor, the former captain of Boothbay Harbor charter boats Appledore and Eastwind made a mistake, a nearly fatal one, as he describes it in his non-fiction book, “A Moon and Square Stern Canoe.” The short book picks up where his last, “Creative Anticipation,” leaves off. That one details Smith’s long recovery from a 2004 car wreck. 

The incident last July as Smith headed solo to Camden, on one leg of a trip to Roque Island, left him unhurt, and thankful.

“It was miraculous. If I hadn’t worked on (the sit-ups), I wouldn’t be talking to you. I’d be at the bottom of Penobscot Bay,” Smith said Sunday. He also credited a survival instinct he said God instilled in him and faith his parents gave him.

In the interview, as in the book, the Coast Guard and Merchant Marine veteran recalled getting up to stretch his legs and then sitting on the canoe’s starboard gunnel. That was the wrong place to sit, he said; the canoe heeled and his back landed in the water; he clung to the gunnel, then did the “extraordinary sit-up” that saved him, landing him fully back in the craft.

Wife of 42 years Doris Smith said she would have wondered what caused her husband’s death if he’d never returned. “It would have been terrible for me. But he’s got to do what he’s got to do. I think he’s a lot more courageous than I am.”

She would rather be in a plastic kayak than a wooden canoe and isn’t comfortable with some of the adventures her husband takes. But that’s what he loves and if being out on the water ever claimed him, at least she would know he was doing what he wanted instead of sitting home watching television, she said.

“I couldn’t have said to him, ‘Don’t do it.’ That’s his life. And isn’t it better to have died doing something you enjoy?”

The day of the incident, she met her husband in Camden as planned; then she saw his wet clothes and learned about the mishap. The couple headed home to North Newcastle Road and later returned to Camden to trailer the boat to Jonesport where they had a camping reservation. Then they fulfilled his 30-year dream of visiting Roque Island. He’d wanted to ever since a friend told him about the place. The book notes that as they headed away from the island, Herbert Smith wondered if it’s better to leave a dream unfulfilled. Asked about that, he said he still wonders. Roque Island wasn’t a let-down, but the dream was done, he said. “Just to keep striving toward it, that’s the enjoyment of it. After you’ve achieved it, it’s over.”

“Creative Anticipation” carries the message that anticipating something good can help it to happen; “Moon and Square Stern Canoe” imparts further advice, along a similar theme, to always have goals. “Keep your goals going. Dreams never run out at any age ... I hope people get that from (the book),” he said.

Smith also hoped readers will enjoy the book’s many local references that were part of the trip, including Sheepscot Village’s reversing falls and Boothbay Harbor’s Townsend Gut.

His close call in the canoe has not deterred Smith from further outings in the 1936 craft named Christy. Next summer, he plans to take it to Stonington. “So, there’s another dream.”

Smith used acrylics for a painting on the new book’s cover depicting a canoe on a moonlit shore. He said Sherman’s Books and Stationery in Boothbay Harbor and the store’s other locations will carry the book.