Dean Simpson, 57, from East Broyle, and his 19-year-old son Zac will be part of a squad of former navy seals and diving experts making the 1,350 metre climb on September 1 in a relay up the mountain side.
Proceeds from the unique expedition will be split between the family of Thai diver Saman Kunan, who died during efforts to rescue boys trapped in a flooded cave, the local mountain rescue service and the Historical Diving Society, which is supplying the suits.
The man behind the idea is Dean’s friend of 30 years Ginge Fullen, who is aiming to climb every mountain in the world.
Dean said: “He lives near Ben Nevis, it’s what he sees when he wakes up in the morning and he thought, let’s climb it in a diving suit.
“This isn’t one of the ones you see in the London Marathon, it’s a proper, full-on 80 kilogram suit. It’s going to be horrendous.”
The team of around six climbers will take it in turns to climb dressed in one of two suits, with others helping them in and out of the bulky gear in time for the next handover point, stopping to camp.
As an added challenge, the trek will begin with a five metre dive into Loch Linnhe before the 1,345 metre assent. Dean said the suit helmet alone weighed 25kg.
“We’re thinking about 100 metre stints in two suits,” he explained.
“We think it’ll take about four or five days. It’ll be quite challenging – that’s an understatement – but most of the guys are ex-navy clearing guys, bomb disposal.”
The father-of-two said the team had a connection to the Thai diver, who was a former navy seal, as most of the participants knew each other through the navy.
In his own career, Dean has cleared several thousand mines in Iraq, Libya and Africa and is still involved with diving and clearing work, although he’s now retired from the navy.
He said he had done charity challenges such as a cycle ride from London to Paris, but the climb was ‘a bit of a one-off’.
“I don’t think it’ll be done again,” he said.
So far, sponsors have raised more than more than £1,400. Donate at www.justgiving.com/crowdfunding/subseatosummit