On board Besso, day one of the Round Britain and Ireland Challenge is hectic, exhausting and, at times, bewildering.

The start of the race is a flurry of sheets and winches as we tack while crossing the Royal Yacht Squadron line just off Cowes. Our initial tactics are conservative: we don’t want a stiff time penalty for starting too soon. If anything, we err on the side of caution: we’re last over the line and left chasing the other yachts towards the Napoleonic era forts guarding the entrance to the Solent. But as the afternoon wears on we claw back some of the lost distance.

As we tack back and forth south of the Isle of Wight, it’s hard to work out the relative positions of the fleet: it’s like watching a 4x400m relay race before the staggered start has unwound.

The remainder of the day is a disorienting mix: spells of dreamy lassitude followed by sudden bursts of activity. For long stretches of time, we simply sit, or slump, on the high side of the yacht, using our bodies as ballast in an attempt to keep the boat as flat as possible and thereby maximise the efficiency of the sails.

In this posture, it’s all too easy to doze off: a lifejacket makes an excellent travel pillow. But then comes a change of tack and we must suddenly turn ourselves into the coiled springs our skippers have exhorted us throughout training to be.

The combination of action and inaction leaves me drained of energy. Never has grinding winches seemed so tough. I feel as though I’m striving to live on an alien planet with much denser gravity than on Earth.

There’s no let up, though; at least, not yet. At eight o’clock we go into our watch system: four hours on, four hours off by night, six hours on and off during the day. We’ve been divided into ‘Gin’ and ‘Tonic’ watches (no reflection, I must stress, on the sobriety of the crew: the boat is dry for the duration of the race). My watch, Tonic, is on duty first.

The four hours are uneventful. As the sky darkens, we peer at the lights of a handful of our competitors, trying to guess by their colour (white aft, red port, green starboard) what tactics are being adopted.

At midnight we’re relieved – in more than one sense of the phrase. But barely have we stripped off our lifejackets, foulies and fleeces and crawled into our bunks than the yacht changes tack and we must gather our sleeping bags and stumble to the new high side of the boat. We’re so exhausted, though, that sleep comes swiftly in our unfamiliar bunks.

0330 comes around all too soon, however, and we’re roused by Gin (the watch, of course; we only get tea to drink when we go up on deck). It’s tough going back to work after such little sleep, but a beautiful sunrise and the revelation of the gains we have made during the night over our nearest rival, Save the Children, are our rewards.