The (Almost) Wreck of the S/V Sail Quest

Last night we anchored in Allen's Cay. This is a fascinating collection of 22 cays, that has a fairly sheltered harbour between them. While you may be sheltered from wind and waves, it's not sheltered from current. In fact, the current comes through in some very strange patterns.
We dropped anchor in the north east corner of the anchorage, near the ruins on Leaf Cay, and set the anchor well, or so we thought. Come the middle of the night we wake because the wind is blowing backwards on the boat, not from the front. We get up to see what is going on and find the anchor has been dragging. When we tried to pull the anchor up, we found that the chain was totally twisted as for several hours we had been circling around our anchor. Kyle, Rebecca, and I are trying to untwist the anchor chain and get the anchor up, when Charlena says, in an alarmed voice, "Are we suppose to be that close to the rocks?"
"Where's the light... Kyle, shine it over there... F__K!!  STARTING ENGINES!"
Less than a boat length away, is a 3 meter high wall of rock with waves breaking on it. No time for the glow plugs, straight onto the starters. Seconds later, the twin diesels fired up and I threw them into reverse and increased throttles to max 3200 RPM. We started backing away from the rocks, dragging the anchor as we went.
We moved off a safe distance, and I throttled down, staying on the helm to keep us in position, while Kyle & Rebecca were now able to recover the anchor.  With only the light of a flashlight to guide us, we turned and crawled slowly forward, over a sand bank and over a blue hole.  Safely out of the current now, we dropped anchor again. We were now in a small circle of shallow sand, with a deeper hole in the center (picture a doughnut). This way, if we should start to drag again we would go onto the shallow sand and bottom out.
We set our anchor alarm on to alert us if we dragged again, and for the rest of the night took turns staying up for a few hours watching the boat's position.
The next morning, we were still safely in the same place. Around 7:30 one of the other sailboats pulled anchor and left, so with the sun up, we started up the engines and crawled out of the shallows towards the now vacant spot. We gently grounded twice, but backing up a little allowed us to find a slightly deeper path out. 
Tonight we will again take turns on anchor watch to make sure we don't drag again. But first it's off to the beach to meet some of the local Iguanas.
The Allans Cay Iguanas existed across the entire Bahamas at the time Columbus discovered the chain, but sometime after that they went extinct. Today they exist only on a few islands. Their scientific name, Iguana Iguana, comes from Spanish, which in turn comes from the local Arawak native word "Iwana". These small scaly creatures have only a few centimeters of ground clearance, but can be up to 2 meters in length. While the Iguanas on Allans Cay will come out to the beach looking for handouts from tourists, be careful as they are not tame and can be vicious.
Follow Up:
We stayed for two more (mostly sleepless) nights before calling it quits and heading to a better place, Norman's Pond. More on that in the next post. But we found out why we dragged that night, when we thought we had set the anchor very well. Most places where the ground is sand, that sand is deep. But in Allen's Cay, the bottom has a thin layer of good sand, but it's over a hard clay layer. So while it looks like your anchor has dug in well, it only goes down 20 to 30 cm before hitting hard clay and will just scrape across the surface. Add in the strong currents coming between the cays with the tides coming in and out, and it's a recipe for disaster.  The only safe place to anchor here is at the south end, in the lagoon of the "U" shaped SW Allens Cay.