Thursday, March 3, 2011

Deivery Day 20


Sunrise...
A pod of three Sperm whales break the surface near the boat. Their spouts glisten silver in the light of the rising sun.
On the starboard bow a Yellow-nosed albatross paces the boat, gliding serenely and slowly at deck level. Startled Flying fishes scatter across the sea ahead of us and behind us the Petrels weave and swoop in our wake.
Xtra-link is making good speed under masthead asymmetric spinnaker and full main. Another great day in a voyage that has not had more than one full day of rough weather.
There is a misconception that if the race to Rio is downwind and easy the return leg must be upwind and difficult. This is my 26th crossing of the Atlantic and experience has taught me some lessons about making easy, safe and fast passages.
Understanding the causes of the weather is obviously critical and what happens on the voyage from South America to Cape Town is directly affected by things that happen as far away as the Equator and the South Pole. I'm not talking about Zen and the beating of a butterfly's wings, but rather about how much affect the angle of the sun's rays has on the heating of the earth. At the Equator the sun's rays are almost perpendicular, causing the surrounding air to heat up intensely and start to rise into the typical thunder clouds of the Doldrums. At the South Pole the horizontal rays are dissipated through the atmosphere and the cold air sinks to the surface of the Antarctic continent. As the Equatorial air rises it cools and also starts to sink, gradually settling back down somewhere near 30* South. As it settles to the surface the rotation of the earth causes this air to start spinning in an anticlockwise direction, giving the South easters which are common at the start of the Cape to Rio race, the easterly winds that develop in the middle portion of the race and the north easters that are often experienced near the coast of Brazil. As these winds revolve around the centre of the high pressure they begin to warm up again and some return to the Equator to begin the cycle once more, but the rest of the air continues southwards like a great, invisible, rolling wave, hundreds of kilometres across and with an enormous mass. Meanwhile the cold air over the high Antarctic plateau continues to cool and starts to tumble down toward the sea like a mighty avalanche, hitting the coast with fearsome katabatic winds. This avalanche of cold air then continues northwards, rolling and swirling like a tsunami until it collides with the warm air from the north and both air masses start to revolve clockwise around each other in the southern ocean, like two wrestlers looking for each other's weaknesses. The warm, rolling air from the north is what we look for to push us along, smoothly and fast across the Atlantic. Running in the pre-frontal conditions is like surfing a massive wave of air. It is clean, pure sailing, but in the back of your mind you are always aware that the wave is eventually going to break and you are going to fall off. The passage of the cold front, when the cold Antarctic air finally catches you, is like the breaking of the wave, and all of a sudden the wind goes crazy, swirling around and gusting manically, driving rain into your face and spray across the boat.
Pre-departure passage planning, reading such excellent books as Ocean Passages for the World (first published in the 1800s but still highly relevant today), and studying the latest satellite imagery from sources such as ASCAT and EUMETSAT, can be likened to sitting on the beach and studying the set of the waves, learning what has been before and what the present patterns might hold for the future. At sea we analyse the forecast data and run the GRIB files through sophisticated routing data to help us decide the best route through the tumultuous waves of the Antarctic and Tropical air masses. Like the surfer riding his board and watching and waiting for the right ride, we constantly assess how we are performing as we ride the wave of air, and always think of the best position to be in when the wave suddenly does crash over us. We don't want to be too far north, otherwise we never catch the wave and are constantly frustrated by the calms and light headwinds.
But too far south and the power of the crashing wave can be devastating. The old sailors on the clipper ships had a saying referring to the ferocity of the southern
storms: "Below 40 degress south there is no Law and below 50 degrees south there is no God". Our passage homewards has kept us on the side of the Law and of the gods but taken us far enough south that we have had a good ride on the wave of air, which has pushed us further and faster than the boats that remained to the north of our track.
We now have 230 miles remaining to get to Cape Town so hope to be alongside by midnight tomorrow. I will give a more precise ETA before mid-afternoon tomorrow. At the moment we are motorsailing slowly while waiting for the final south easter to build up this evening.
Once we are home Phillippa and I will be back to preparing our boat, Phesheya-Racing, to compete in the Global Ocean Race in September. By completing the Global Ocean Race we will become the first South African team to complete a double-handed race around the world, and the first South African boat to complete a racing circumnavigation in 13 years. For more details about our campaign keep an eye on our website: www.phesheya-racing.com where you can also join our Facebook page.

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