A former SAS soldier is fulfilling a decades-long dream by rowing solo across the Atlantic.

Ian Rivers, 55, will set off from New York on Monday, weather permitting, and will spend around three months on his own rowing the roughly 3,500 miles back to St Mary’s in the Isles of Scilly.

“Doing the row solo is the ultimate challenge really because it’s just me with my boat against the elements, the conditions,” he told the PA news agency.

“I’m hugely, hugely looking forward to actually getting under way.”

The seed for the idea of the solo row was sown back in the 1980s when, early on in his 27-year military career, Mr Rivers was staying in Plymouth’s Royal Citadel, which looks out on the water.

“I’d quite often look out there and read about the exploits of ocean rowers crossing the oceans,” he said.

“And I always thought that one day I’d end up in North America – I wasn’t too sure where at the time – and I’d row back home to the Isles of Scilly.”

Around 18 months ago Mr Rivers – who left the military in 2011 after 21 years in the SAS – started planning the trip for real.

To make life more difficult for himself, Mr Rivers, from Hereford, is attempting the journey without the use of GPS to navigate.

He believes he will be the first person to row the full northern Atlantic full route from New York to the Scillies using celestial navigation.

“The way navigation is done now, you jump in your car, you whack a postcode in there, you arrive at your destination, and you’ve missed the journey,” he said.

“The same thing can happen in ocean rowing… you literally put a waypoint in, tell the boat to go there, before you know you’ve arrived there and you’ve kind of missed the experience between going from A to B.

“So for me, because it’s the adventure, I wanted to go back to how seafarers first crossed oceans and actually knew where they were.”

While Mr Rivers will be navigating the old fashioned way using a sextant, there will be a GPS tracker on his boat – although he will not have access to it.

Instead, people at home will be able to follow his progress and compare his actual location to where he thinks he is, his best estimate for which he will submit every day.

While he said he misses the “camaraderie” of the military, he said he never considered doing the row as part of a larger crew.

“If I did it with someone else, I’d only probably row half of it, because the other person would row the other half,” he said.

“When I got to the Isles of Scilly, I’d almost think to myself, I need to go back there and do it myself.

“And the challenge of being on my own…the loneliness or coping with that and psychologically being strong during that period is one of the challenges that I’m actually looking forward to.”

And while he will not have any human company, he will not be completely alone on the boat, thanks to a present from a friend of his.

He explained: “He’s a veteran and his daughter, Penny, who’s 10 years old, she was concerned that I was going to be on my own for that period of time.

“She insisted that I take her teddy bear, which is an SAS teddy bear – you can’t buy them in the shops, you can only get them given to you from people that are serving.

“She’s called him Captain Paddles, and so I’ve got Captain Paddles as a companion on the row back.”

Referring to the film Castaway, in which Tom Hanks’ character starts talking to a ball with a face painted on it, he added: “I think I might have a Wilson moment – if I need to talk to someone, it’ll be Captain Paddles instead of Wilson.”

Mr Rivers has named his Rossiter Ocean 2 boat Sentinel, in honour of the Special Air Service Regiment Association’s (Sasra) mental health programme of the same name, which promotes support between veterans to help recognise mental health issues.

He will be aiming to raise £500,000 for Sasra and St Michael’s Hospice in Hereford.

To donate, go to virginmoneygiving.com/fund/sentinel