Joy Smith's Blog

The Gulf Stream has always been an enigma to me, even though I’ve traveled it several times. Oh, I know it affects weather and that it’s considered nautically challenging and can be disastrously rough at times, but that’s about it. Recently I set to work trying to make sense of it all, initially stymied by the scientific lingo, and was not only fascinated by its the intricacies, but now I understand how yachtsmen use its power to win races.

The Gulf Stream is the most influential of the four currents that make up the North Atlantic Gyre, a huge oceanic circulation system driven by wind and the earth’s rotation. It is shaped by the continents in the west and the Sargasso Sea in the east. Located in the Atlantic Ocean, The Gulf Stream originates in the Gulf of Mexico (thus the name “Gulf” Stream), exits through the strait of Florida and follows the eastern coastline of the United States and Newfoundland. This constantly moving and changing body of water within the Atlantic Ocean runs 40 to 50 miles wide with a current of 2.5 to 3 knots, a speed boost when you are running with it. Its position shifts to the north at the onset of winter and to the south for the spring and summer seasons.

Scientists worry that global warming will melt the artic cap, diluting the salinity of the Gulf stream waters, and making them so light that they won’t sink and head south. It’s frightening to learn that a shut down of the Gulf Stream would chill the North Atlantic, causing temperatures in Europe and North America to drop by 5 or 6 degrees F, 5 degrees shy of ice age temperatures.

Navigating the Gulf Stream has been a yachtsman’s challenge since the early 1500’s, when sailors noticed that in certain areas, where the water was warmer, their boat speed increased. There was no means to record this until the development of the thermometer, which allowed them to measure temperature change and seek the warmest waters. Using the thermometer, Ben Franklin made the first attempt at charting the Gulf Stream, but it wasn’t until infrared cameras were available to take aerial photographs that it was possible to document the latitude and longitude of its hot spots.

In the North Atlantic, it’s probable you are traveling within the Gulf Stream when instruments registering water temperature show an increase of 60 to 70 degrees. Yet, the Gulf Stream is constantly moving and changing. In some cases, The Gulf Stream wanders from its main body, creating a bend or loop, aptly named “a meander.” A meander can extend over 100 miles before rejoining the Stream and has northbound and southbound legs. In a northbound meander, the warmest water and the fastest current is usually near the northern side of the stream. In a southbound meander, look for it on the east side.

If you are traveling between the northeast and Bermuda, the Gulf Stream appears wider than normal, because it encompasses a meander. The key to managing this trip is to use Gulf Stream charts to identify the latitude and longitude of the area where the meander begins, at the bend, or “knuckle,” and to set course toward it. Once you’ve turned at the knuckle, carefully monitor the water temperature. If the temperature drops, it could mean you have chosen the wrong leg of the loop. If it holds steady, adjust your course to find areas with the warmest water.
Once you have this meander thing down pat, we can move on to eddies, for these are runaway sections of meanders. When a meander increases so much that it breaks away from the main body of the stream, it captures a cell of water and whirls around it in a circular motion. The Gulf Stream sheds close to 60 cold and warm water eddies per year; both types are documented on Gulf Stream charts, appearing as small “storms,” with the fastest speed at the perimeter and in the eye, stillness. If you are going against the flow of an eddy, the seas will become noticeably lumpy.

If you are traveling with a cold eddy, which is circular and rotates counter-clockwise at 2 to 4 knots, you will find greatest speed at the outer third of the eddy. Cold eddies tend to drift to the southeast a few miles a day. Warm water eddies are weaker, spinning clockwise-- the opposite direction of a cold-water eddy-- at 1 to 2 knots. These drift to the southeast, and when traveling south to Bermuda, it’s easy to confuse a warm water eddy with entering the main body of the Gulf Stream.

The most popular means of keeping abreast of Gulf Stream current flow is to consult Jennifer Clark’s website (http:/​/​users.erols.com/​gulfstrm). Before you set out, also check the marine weather forecast for the duration of your trip--from the Connecticut area, for example, it takes 4 to 6 days to cross to Bermuda by sailboat. When a storm is predicted, have the good sense to wait to depart, especially if the wind is coming from the northeast. Winds opposing the Stream’s direction create standing waves, causing lost rudders, broken masts and blender-like conditions aboard. The strait of Florida, the 50 mile span connecting to the Bahamas, can be particularly feisty, as a current from the Caribbean and one north and east of the West Indies join to pour through this area.

Understand that the challenge of traveling within the Gulf Stream is not survival, but figuring how to use it to your best advantage. When planning a crossing, do your homework to make your experience a positive one. Banged up boats and crew are no fun, and repairs are costly. Only depart in favorable conditions, use your instruments to gain speed by locating the warmest waters and travel as much as possible with the flow of the current. By doing so, when you and your boat arrive intact at your destination, you’ll be able to celebrate your success, instead of moaning over your disasters.