Tuesday, March 13, 2007

Day 6 Finally... wind

The Northeast trade winds
The answer to my question about the depth gauge is that it is likely to be fish swimming under the boat. I am told that sometimes they follow a boat for hundreds of miles. We have been towing a fishing line during the day since we left hoping that one of them would wander back and snack but so far we have only had one bite and no fish caught.
Our course from PV is intended to take us South West so that we cross the equator at about 127ยบ32’ West longitude. This route is predicated on finding the narrowest part of the Inter Tropical Convergence Zone (ITCZ) otherwise known as the Doldrums.
A moment on wind. The air over the equator is warmed by the sun and rises pulling in the air from the Northern and Southern hemispheres. Near the Equator, this rising air is moved sideways by the rotation of the Earth and becomes the Northeast and Southeast trade winds. Where these two wind systems meet (the ITCZ), there is very little wind so we are seeking the narrowest part.
Every day at 6:30 AM PST, a ham radio operator named Don Anderson from Oxnard, California broadcasts a report of weather conditions in the Pacific including a 6 day forecast. By combining his report with an e-mail from the National Weather Service, we can guess several important things: 1. Shape and location of the ITCZ and 2. Location of the Northeast trade winds.
Until today, we have been North of the trade winds. Our wind has been from 1 to 10 knots and the seas have been relatively calm. Our boat speed over ground (SOG) was from 1 to 4 knots meaning we were making about 80 nautical miles per day. From PV to Hiva Oa in the Marquises is 2810 nautical miles (~3000 statute miles) so this would take us 33 days at that rate.
In the early afternoon, today, we found the NE trade wind. The sea became much more active and the wind picked up to 15 to 20 knots. Our boat speed improved to 6 to 7 knots. At that speed and with a remaining distance of about 2400 nm, we would reach the islands in about 16 days. It is nice to feel this wind but the downside is the boat rocks a lot making cooking and sleeping a bit difficult. It’s the silver lining and the dark cloud effect.

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