Star partners Iain Percy and Andrew ‘Bart’ Simpson may share a common goal, but they represent two different sides of the same coin.

Percy, lean and chiselled, standing 6ft 2in, brought a new level of physical fitness from the Finn into the Star and proved a wake-up call for many helmsmen in the fleet. Straight- leg hiking became his trademark and his six year dominance of the class brought two Gold and four Bronze medals in the Star worlds between 2002 and 10, two Golds in the Europeans and an Olympic Gold in 2008. Simpson is just 1in shorter, but his extra 13kg represents a beefy stature, a physical reflection of the more grunty nature of his role aboard the Star.

Percy the thinker, Simpson the doer is an easy and understandable conclusion to reach for looks and basic stats alone – but it’s the wrong one. The reality is the reverse.

The pair have known each other since childhood, on and off the water, which has led to the fostering of a close, unspoken understanding that has allowed a subtle, sophisticated blend of teamwork to develop.

Percy is a confident speaker, intelligent, articulate and always ready to front up to the press, even when things have gone badly. After a disastrous 2004 Olympics, when he finished 6th, and a chaotic America’s Cup campaign in 2004-7, his quick-witted, frank public appearances gave a clear indication of a mind that is constantly buzzing with ideas.

Behind the scenes, it is Simpson who provides the calm, considered rationale.

Both studied economics at University, both use their analytical skills to unpick the details of a complex and technical boat, but each use their ability in different ways. For Percy, the solution to a problem could just as easily come from exploring the boundaries, as from the more likely middle ground. When it comes to developing a strategy, he takes a relaxed approach, preferring to let the best ideas rise to the top.

“I like to keep our debriefs informal, usually over dinner or tea,” he says. “I like to sleep on various scenarios, especially if I think I’ll be stressed the next morning.”

Percy is an avid BBC World Service listener who admits to leaving the radio on overnight while he sleeps. In his intense, determined, performance- obsessed world, it is perhaps the only time he gives his mind to absorb, reflect and develop. But it clearly works.

At their winter training camp in Portugal, Iain Percy and Andrew Simpson share a crew house with their training partners, their coach and data analyst. The living area looks like a cross between a boatyard with comfy chairs and an internet café – laptops, iPads and iPhones litter the room along with data loggers, chargers, batteries and Pelican cases. Outside on the balcony, wetsuits, spray tops and rash vests hang from the railings, while shoes and sails sprawl over the terracotta tiles.

A dispute with the landlord over costs means the heating has been turned off in their stone-walled, stone-floored Mediterranean-style house, which now acts like a refrigerator. The cold, the clutter and the collective focus on performance analysis, technical development, data logging, physical training and the odd period of blue-sky thinking, creates a team buzz that you can’t miss.

The atmosphere is akin to student digs, but each day is filled with ideals, goals, views and debate. It’s stimulating stuff, yet running quietly underneath is a continuous distillation of ideas and assessments as to the direction the programme is taking and the decisions to be made. This is Simpson’s domain.

Simpson is not your typical sailor, but he is typical of many sailing Olympians whose long-term dedication to a campaign sets them at odds with amateur sailors. As a training partner to both Iain Percy and Ben Ainslie he has watched and helped them both collect their Olympic medals. So it was no great surprise when his turn came in 2008 that he knew the form and came away from his first Olympics with a Gold medal.

Among his ambitions he lists a job in the City; among his interests, playing the stock market. Quietly spoken, disarmingly polite and diplomatic, Simpson is easy to underestimate. You sense he likes it that way.

Recently married to Leah Simpson, he’s clearly besotted with family life and his eight- month-old son as he flicks though the family snapshots on his iPhone. His dry, razor sharp wit comes through as he describes his favourite non-sailing item as a knife and fork.

It’s easy to see how his character complements that of his best friend Percy. They have similar minds, identical degrees, both rate the Finn as their favourite boat and delight in straight leg hiking their opponents into their wake. They are the perfect fit, both for each other and for the boat.