IT’S one of the most common, not to mention ridiculous, sporting conversations held throughout Pembrokeshire every September.

When two non-triathletes briefly discuss Ironman Wales, one will invariably say: “I’d be fine on the swim,” before justifying the boast with tales of retrospective school swimming badges or regular morning visits to the pool at the local leisure centre.

Admittedly, it was a theory I used to apply to myself, before a 750-metre sea swim in Solva harbour a few years back left my legs every bit as wobbly as my eyesight.

So at least I was under no illusions about the size of the task when last month, I met Claire Stubbs for our third and final training session before she set off for Kona, Hawaii, to compete in the 40-44 years old category in the World Ironman Championships.

Our previous sessions, that had covered both the running and cycling disciplines, had seen me just about hold my own despite Claire’s obvious compassion for my slower pace.

But today was going to be different. After all, keeping track of a superior athlete when road running or moving on a bike is one thing – but doing so with water filled goggles and crashing waves impeding you is another.

Claire meanwhile, who will be competing in Hawaii on October 8th, was at the time in the process of tapering down her distances in all three training disciplines to ensure she was in 100% condition before travelling to the World Championships.

In June, she spent 10 days warm weather training in Almeria, Spain, while victory in her age group at the recent Saundersfoot sprint distance triathlon suggests she’s on course, literally, to fulfil her ambition of reaching the finish line in Kona.

However, she admitted to me that her recent preparation had been tinged with frustration when Ironman Wales, an event she has made no secret of her love for, again came to Tenby on September 18th.

Claire competed in the event in both 2014 and 2015, the latter performance qualifying her for Kona, but given the close proximity of the event to the World Championships, was forced to spectate this time around.

“We had friends staying who were taking part so Steve (Claire’s husband) and I were up from 4am to support them,” she said.

“I really enjoyed it and watched the whole day. But I was also frustrated and a bit jealous of everyone because I wanted to be out there myself.”

I’ll be honest, as we arrived at North Beach, Tenby, on this particular early Thursday morning, one thing I didn’t feel towards Ironman athletes was jealousy.

However, I could at least take solace from the fact that the weather gods had been kind. Far from the horror tales of ‘UFC on a waterbed’ and ‘an underwater royal rumble’ that Ironman competitors had described to me in the past – today the sea was calm, the sun was out, and it seemed as if the pair of us had an ocean to ourselves.

And thankfully, I’d managed to borrow a wetsuit off friend Anthony Hayward, himself a keen triathlete who took part in the 2015 Ironman Wales event. So at least I looked the part, even if I didn’t quite feel it.

The early stages proved a false dawn, as I managed a steady pace and a rhythm that I could at least partially relate to my occasional morning swims in Haverfordwest Leisure Centre.

It’s fair to say, my stability didn’t last long.

I soon discovered what the term ‘hit the wall’ really meant as my arms suddenly felt like lead, front crawl became breast stroke, my breathing patterns became frantic, and the safety of the beach appeared miles away.

The clear waters that morning allowed me to see all that was swimming alongside and beyond me. Had the infamous Tenby jellyfish decided to make me a target, they wouldn’t have had to exert themselves too much to catch up.

Claire briefly slowed down in order to instruct me on my breathing, and of course allow me to catch up, and the scale of the task that Ironman competitors face in having to maintain a good pace for 2.4-miles was suddenly hitting home.

And so was the difficulties they must encounter when sharing the water with around 2000 other swimmers. Even with just two of us, and with my sense of direction and composure both long gone, I occasionally found myself crashing into Claire.

What of course didn’t help, was my purchase of what I considered to be a cheap yet decent enough pair of goggles the previous day, which I found myself having to empty every few seconds as they filled with sea water.

I guess in terms of both expense and training, there really are no short cuts for Ironman preparation.

Eventually I made it back to the safety of the harbour, having done little more than half the full Ironman distance. And just as well, as any attempts to complete a second lap would probably have resulted in a wake call for the local RNLI.

However, the ordeal didn’t quite finish there, as my spinning head and ‘jelly’ legs contributed to a more than unsteady walk back to the car park – whilst the coffee I drank an hour later tasted like it might as well have been mixed with sea water as opposed to milk.

Claire on the other hand, looked like she'd just emerged from a relaxing hour in a hot tub.

But on a serious note, her ordeal next weekend will be anything but comfortable, as for a start, Kona rules forbid athletes from wearing wet suits.

“I’ve done a couple of sea sessions in my swimsuit and it’s been freezing,” she admitted.

“Although the water should be warmer out there. Mind you while we worry about jelly fish, over there they worry about sharks.”

And I thought I’d just had it tough.

Those who have followed Telegraph Sport’s first two features on Claire, will be fully aware she’s not the type to lose sleep over competition. Her attitude to endurance events is refreshingly laidback and fun loving - and intricate training schedules and obsessive dieting are not for her. She sticks to what works, and thus far, it has served her pretty well.

But ahead of what she describes as ‘a once in a lifetime event’ for her, surely some nerves must be kicking in?

“Not at the moment,” she insisted.

“But maybe when I get out there (Hawaii) they will.

“I’ve been checking the conditions and the winds are very strong. It’s going to be a real challenge.”

But it’s not one that Claire is tackling entirely alone.

She has made no secret of her gratitude to husband Steve, son Tom and daughter Jazz, who have not only supported her throughout her preparation (they are travelling with her to Hawaii) – but have even joined her during training sessions.

Claire herself previously she told me: “I couldn’t have done all this without them and I’m so glad they can be there with me in Kona.”

And regardless of how she goes on October 8th, her meteoric rise to a World Championship competitor, after only deciding to take up endurance events whilst watching Ironman Wales ‘on the beer’ in September 2013, will always go down as a remarkable achievement.

Personally, she’s also given me a fascinating insight into just a snippet of the training required to conquer a 2.4-mile sea swim, a 112-mile bike ride, and a 26.2-mile marathon, not to mention all in one day.

But I suspect unless you’ve competed in such an event yourself, you can’t truly appreciate the dedication that athletes like Claire put in, and the extreme pain they put their bodies through to excel and for that, they all have my full respect and admiration.

Oh, and next time someone casually tells you they would be fine on the Ironman swim – unless they’ve trained intensely in the sea for the past few months………don’t believe them.

Throughout the year, Claire has been fundraising for the Tenby RNLI and has currently raised more than a £1000 for the charity. Anyone wanting to find out more about her efforts, or is willing to sponsor her, can contact her on the Claire4Kona Facebook page, @Claire4Kona Twitter page, or via petal9060@gmail.com. She is grateful to Nd Toy and Partners Insurance; The New Inn; The Nook; Rembrandt Jewellers; Tenby House Hotel; 1 Formula Fitness; and Steve Davies, managing director of Pure Healthcare Staffing, for their help with sponsorship and her preparation.