Saturday, April 08, 2006

Energy Boost

At Sea, 24 49N 080 26W

We're getting an energy boost today but not from drinking Gatorade. We're riding the Gulf Stream. It's great in these conditions. The winds are only 13 knots from the south, but we're moving 6-7 knots eastward. Soon we'll begin turning north. I can't say for sure how much boost we're getting, the knotmeter is gunked up with barnacles again, so we only have speed from GPS. My guess is 2-2.5 knots boost. It could be as much as 4 knots in the right conditions.

Our nice southerly winds are reputed to turn northerly on Monday so we won't be able to make it up the coast in one passage. We'll put in (hopefully) at Lake Worth (West Palm Beach) or Fort Pierce. Darn, if we had only left 24 hours earlier we would have had a shot at a nonstop passage.

The Gulf Stream is one of the true wonders of the world. It has a major influence on all the world's weather. The Gulf Stream transports heat and salt from tropical waters to subpolar regions. It starts off Northwestern Africa and it passes north of Venezuela it is turned north by Central America where it becomes the Yucatan Current (of which we had some recent experience) It is turned eastward again by the coast of the USA, turned north in the Florida straights between Florida and the Bahamas. It leaves the US east coast and heads for Northern Europe around Cape Hatteras.

The warm water from the Gulf Stream is what makes Western Europe's weather so mild. Think that Rome is at the same latitude as New York but Rome is much warmer.

In the northern Atlantic, the Gulf Stream waters are cooled, and they also get mixed with fresh water from Greenland and the polar region. Cold fresh water is more dense than warm salty water so it sinks to the bottom of the sea. Then the current flows southward following the sea bottom all the way to Antartica, westward across the Indian Ocean and northeastward across the Pacific Ocean. In the North Pacific the water rises to the surface again being warmer and saltier than the surrounding waters. The current then reverses its path, this time on the surface, until it returns to Northeastward Africa.

Because of the Gulf Stream, Western Europe and Western North America have mild climates whereas Siberia and New York have colder climates.

Historically, the Gulf Stream has abruptly stopped and reversed directions several times. The reversal brings on a new ice age. I hope it doesn't happen tonight when I'm sleeping (ha ha).

I wish I knew how many joules per second of energy is transported by the Gulf Stream. Perhaps one of my blog readers can google that question and email me the answer. If we could harness it, we could perhaps supply all the energy needs of the whole North American continent. Of course if we harnessed more than a small fraction of the Gulf Stream's energy we would cause massive climate changes.

Hmmm, another interesting engineering project. If the Gulf Stream current boosts Tarwathie's speed from 5 knots to 7 knots, how many joules per second (watts) of energy am I harnessing? I think that answer is somewhere around 5 kilowatts.

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