A retired maths lecturer has raised almost $33,000 for charities for the disabled from his book about his marathon swim around Bermuda.

Seán O’Connell, 77, has donated cash raised from the sales of Shark Bait since its publication in 2017 to the Bermuda Physically Handicapped Association and Summerhaven home.

Dr O’Connell said: “I never thought I’d reach this amount of money. It’s beyond my wildest expectations.”

He added that the cash raised rocketed when companies started to buy the book for public schools.

He explained: “The idea would be that they would sponsor books for the schools, and then the money would go to the handicapped and the books would go to the schools.

“But I didn’t think it would reach this level of donations and I was quite astonished, surprised and delighted by the positive response from so many of these firms.”

Dr O’Connell said 28 companies had bought books and the biggest single donation was $2,000 from reinsurance firm Arch.

He added that he was invited to speak at Dellwood Middle School and the Berkeley Institute to discuss the book’s themes of perseverance and the importance of following a passion.

Dr O’Connell said: “The people who are happiest in life are those who have found something they are absolutely crazy about and are willing to sacrifice a great deal for that.”

Shark Bait tells the story of Dr O’Connell’s swim around the island in 1976 after a $1,000 bet with a friend.

The challenge took 43 hours and 27 minutes to complete and earned Dr O’Connell the $1,000 wager and a Guinness World Record the next year.

Dr O’Connell said the swim had been earmarked to help the disabled.

He explained: “I thought if the sharks get me, they’ll take an arm or a leg off and I’ll be handicapped, so I might as well do it for the physically handicapped.”

Dr O’Connell said that the story also had a message for people who had disabilities.

He said: “Handicapped people are so often put down and this was a model message that they should not be discouraged by people telling them what they can’t do, but be fired up by what they can do.”

Willard Fox, the chairman of the BPHA, said Dr O’Connell’s donations had helped fund transport, medical expenses and pensions for the disabled.

He added: “I want to publicly thank Dr O’Connell for all of his fundraising. He has been very dedicated to us.”