Saturday, July 14, 2007

July 13, 2007 - Enroute to the Tuamotus

We've had a great passage - lots of wind and the seas aren't too built up. We're reaching in a consistent 15 - 20 knots of wind, flying along between 6 and 8 knots. Since the second morning we've had two reefs in the main. Tonight we'll probably drop it and sail under jib alone so that we don't arrive at Ahe before dawn.

The Tuamotus (two-ah-moe-twos) are a chain of 77 atolls historically referred to as the "Dangerous Archipelago," a reference to the number of ships that have met their end here. I can't even imagine trying to navigate these atolls without GPS and radar. That would be no fun atoll (sorry, I couldn't help myself).

So what is an atoll? An atoll is one of the last stages of reef development. Imagine an underwater hotspot. As magma wells up from the ocean floor, it eventually forms a submarine volcano. The volcano breaks through the surface of the ocean and creates an island from the lava flowing out of it. Hawaii is an example of an island at this stage of development. Over time, coral starts to colonize the edge of the island, and a fringing reef is formed. Due to the shifting of oceanic plates, islands slowly subside. For example, Bora Bora is sinking at the rate of 1/2 inch per century. As an island starts to sink, a barrier reef develops atop the fringing reef and a lagoon forms between the barrier reef and the island. Eventually, the old volcanic island submerges completely, and all that is left is the vaguely circular barrier reef, upon which sand and coconuts collect, transforming it into a ring of white sand covered, palm shaded islands around a saltwater lagoon. In Polynesia, these little islands are called motus. The ring of islands, or atoll, often has a navigable pass that lets ocean water, fish, sharks and boats in and out of the lagoon.

With the large volume of water that rushes through these narrow passes as the tides change, the tidal currents can be very strong. It is best to shoot the pass at slack tide. We're aiming to arrive at Ahe tomorrow morning in time for low tide and then wait to enter the lagoon during the ensuing slack tide.

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