Resolute of Thames - The Theroy and the Practice

Those of you glued to our little icon on the yellow brick will, I am sure, have noticed we have not actually been heading directly to St Lucia since about mid night last night. Let me (Colin) try and explain.

Firstly, the shortest route across the Atlantic is, on most maps, not a straight line but what is known in the trade as a great circle route. The construction of a great circle route requires special charts or an electronic chart plotter that can do the maths for you. So we left Cape Verde with a series of marks on our charts that took us first very slightly north and then with a series of small adjustments southward to produce something that looks like a small tangent of a very big circle. Then there is the weather. In theory the trade winds (those constant winds which in days gone by blow our forbearers across the Atlantic) should blow constantly from the NNE as one leaves Cape Verde and then become progressively easterly as one crosses the Atlantic. Should you be so inclined a piece of paper with a Cape Verde and St Lucia sketched on it plus a line going in a slight circle north between the 2 and then a few wind arrows as described above will demonstrate that the natural course to sail inverts the great circle.

So much for the theory.

In practice after messing around with every sail we own (see earlier entry by Gilly-Mate) we settled for 2 headsails only one of which is on a pole and we coaxed the Hydrovane into steering with this combination of sails. In effect this means we have to keep the wind coming from about 15 degrees either side of the back of the boat and to give Harriet Hydrovane a chance and us a comfortable ride we have to make sure that the waves or swell (which are not always coming in the same direction as the wind) are coming more or less directly from behind us. Thus, both sails have some wind and the boat just gets lifted by each wave rather than being knocked off course and one of the sails loosing the wind. The racey sailors will now all be crying why does he not have his mainsail up. Well quite simply, dear reader, because to reef (reduce its size) on our boat requires, in anything other than calm conditions, 2 people on deck and there are only 2 of of us and we have a long way to go.

These trade winds are, again in theory, found in a zone between the Azores High and the ITCZ (inter tropical convergence zone - the doldrums to our forebears). Our forecasts are showing some indications of this but we are now at 35 degrees west and the wind is currently a light North Easterly not even a North North Easterly! Which is why we are going southward. However, those nice people at the WCC who provide us with a daily weather forecast and the maps with pretty wind arrows we get over the radio seem to be telling us that there is more wind to the south of the trade wind belt. So, dear reader, we shall continue our drift south. If the boats to the north start to overtake us please do let me know. At some point we will either find the illusive Easterly Trade Winds or we will have to get the mainsail out and make some sort of effort to arrive in St Lucia rather than Trinidad.
Colin