It's dawn on Thursday, another 12 hours of night sailing behind us, and, for almost the first time, one that's been uninterrupted by sail changes, course changes or equipment failures.

Strangely this doesn't mean that sleep has been any less disturbed, night sailing plays tricks with the mind, especially when sailing fast downwind.

We've actually had the steadiest weather conditions of the whole rally, 18/19 knots all night, occasionally increasing to 22kts and sometimes dropping to 16. We've been sailing at an average of 8-9kts boat speed all night (the tracker will show slightly less as we aren't going directly to St Lucia and the speed shown is the component in that direction).

Offbeat revels in these conditions, stable and fast. However the boat is full of noises which play havoc with your perception of the environment, especially on a Nautitech catamaran which has an enclosed saloon, which is great for shelter and security and does provide 360 degree views.

There are three sort of noises onboard; whooshes, bangs and creaks. If you are in the cabins the sound can be very loud, and, as you can't actually see the waves, the sky or the "numbers" (wind speed, boat speed, wind angle), your mind guesses, usually inaccurately, what's happening based on the cacophony of sound.

Everyone on board, me included, has when "off watch", come up to the saloon to find out when or whether we are going to slow the boat down or put a reef in only to discover that sometimes the wind as actually decreased but it's just the noises have changed.

Whooshes are the sound of the water rushing past the hull, as the boat surfs down the face of the wave, in the cabins you can hear an express train of bubbles rushing under the hull as the boat speed increases up to 13 kts before slowing again at the bottom of the wave.

Bangs are when waves hit the hull, as we are nearly directly going downwind these are from waves catching the boat up from behind. Most just lift the stern and gently lower it again but the waves aren't in neat lines, the diagonal ones come between the hulls and smack into the side with a violent jolt, right next to your pillow when sleeping in the rear cabins. Ironically the slower the boat goes the more "bangs" we get. Tonight we've been sailing fast, nearly the same speed as the waves, so few are hitting the boat...hence the visits from the off watch crew (me included!) when the wind is actually lighter.

Finally there are the creaks. There are two varieties: woodwork creaks as the hull moves and the interior walls and furniture rub against each other, each cabin has its own selection of these which you quickly come to recognise. The other variety come from the rig created by the loads of the sails, mast, halliard and sheets. All boat owners listen carefully to these, a change can indicate a potential problem. Tonight though it's been the same sound throughout, a creaking as the spinnaker halliard stretches about 1 cm on each wave, absorbing some of the load on the rig.

Our watch duties are to check the "numbers". Is the wind increasing or decreasing, do we need to change anything, maybe tweak the course by pressing the autopilot buttons or adjust the sails and we need look for ships and other yachts, visually for lights but mostly using the AIS on the chartplotters. Mostly it's just watching, the autopilot does all the steering.

Interestingly each of us on board have found favourite places to do their watch. I tend to sit in the cockpit seats outside the saloon, fresh air but close to the saloon, getting up every 15 minutes or so to look inside and around the horizon; Mike and Sarah, who are doing a slightly longer watch together seem to sit on the seats just inside and outside the saloon doorway able to watch the chartplotter directly; Lucy stays on her feet, mostly by the nav station, but I think Anne-Laure got it right last night, she sat outside clipped on at the helm station away from most of the upsetting "noises" inside, a clear view of the sails, enjoying the wind in her hair, the view of the stars above, and the sound of the waves by her side.