The Banks

At Sea, Bahamas Banks
27 00.84 N 078 00.72 W

The Bahamas Banks are fascinating. I wish I knew more about their geology and history. I promise, the next time I get to the net I'll bone up. For the benefit of readers who don't know, I'll explain what I know.

You have seen pictures of the wonderful buttes in the American West. A butte rises out of a flat desert floor. The walls rise almost vertically. The top is like a flat table. That is what the Bahamas banks are like, but the scale is huge. The walls of the banks rise almost vertically 2000 feet.
The table-like top is a hundred or more miles across. The remarkable thing is that the level of the table top is about 10 feet below sea level. In a few places, the level is a bit higher or lower, resulting in islands and holes, but the vast majority lies just below the surface.

I'm skeptical that it is mere coincidence that the top of the banks lies just below sea level. I wonder if there isn't some feedback mechanism that keeps it that way. I also wonder about the past, when sea levels were higher and lower. Were the banks high and dry at times, and deeply submerged others? I'd like to know.

The shallow flat top also contributes to the fantastic clarity of the water here. The daily tides surge and ebb bringing fresh cool waters from the deep and flushing away soiled and warmed water. I would also like to know how quickly the water turns over on the banks due to tides.

We can anchor almost anywhere on the banks in mild weather. In heavy weather on the banks one is completely exposed to wind and to the wind driven choppy waves, but the huge ocean swells are stopped at the barrier reefs.

Out on the banks the bottom is almost all white sand. We can see clumps of grass and the occasional sponge but there's not much life. I don't think there are many fish either. Predator fish prey on herbivore fish, and there's not much plant life to feed the herbivores.

We're headed for the Sea of Abaco on the northeast corner of the Bahamas. There, a ring of barrier islands protects us from the sea. The sea is deeper than the banks, perhaps 20-25 feet deep in many places. This protected inland sea is perfect for day sailing. Numerous protected anchorages are available if the weather turns bad. There is also more life of all kinds here than on the banks. Just outside the barrier islands are barrier coral reefs. Alas, most of the coral is dead. The few remaining
live spots will be our destinations for snorkeling. Just beyond the barrier reefs is a huge trench, 1500 feet deep.

The Gulf Stream flows northward both east and west of the Bahamas. That helps to make the climate very pleasant. It is warm in the winter. In the summer it is 10-15 degrees F cooler than Florida. They say that it is extremely pleasant to spend the summer in the Bahamas, as long as the occasional hurricane doesn't bother you.

There is very little rain here except in September, I'm told. Almost all houses have downspouts and to catch the rain and cisterns to store a year's water needs. In some of the biggger places, they now have reverse osmosis desalinization plants to make fresh water. Cruisers like us who don't have on board water makers are forced to pay 20 cents up to 50 cents per gallon for (poor quality) fresh water. We use fresh water very sparingly.