Four Royal Navy submariners are attempting to cross the Atlantic in the world's toughest unsupported rowing race.
The team, known as 'HMS Oardacious', is hoping to raise £100,000 for a military charity by rowing 3,000 miles from La Gomera in the Canary Islands to Antigua in the Caribbean.
As submariners, the team are used to the challenges of the ocean - spending months at a time under the waves with no contact to the outside world.
But now they are training for their biggest challenge yet, and for a change, it is above the surface.
Lieutenant Hugo Mitchell-Heggs says the team's day jobs should mean they are well prepared.
"We are used to a watchkeeping routine, and we've operated in scenarios where we've experienced tiredness and sleep deprivation," he told Forces News.
"It'll be something that will hopefully prepare us for this one."
Over the last year, the team has been training hard across the UK.
The Talisker Whiskey Atlantic Challenge is regarded as the world's toughest rowing race with teams facing 40 feet waves, as well as sleep deprivation and seasickness.
Petty Officer Dylan Woods said: "It's a physically arduous challenge, but I'm personally quite worried about the heat.
"A lot of our training we've done in this part of the world and the heat isn't as much of an issue."
Watch: 2018 competitors, 'Men Of Oar', showed Forces News how they will be living at sea.
But as all good teams do, HMS Oardacious are already looking at ways to keep morale high.
"There's humour side of it - you should be able to laugh at every scenario," said Lieutenant Mitchell-Heggs.
"No matter how bad it gets, you should always find the humour in everything, so that will lend itself really well to the challenge itself."
The team will depart from La Gomera on 12 December, where the challenge of the Atlantic Ocean is in their hands.