We spent a lovely few days visiting the Island of Anegada in the British Virgin Islands. After a full day at anchor in the Settling Point anchorage, we started the following day at a lovely snorkeling beach, Loblolly Bay, where we met two nice couples from North Carolina.
Onward we explored to Cow Wreck beach, a long expanse of white sand beach with just a few folks. Our new Tar Heel friends recommended we try the conch fritters at the beach bar, which we did. The fritters were superb and when we tried to pay the waitress, she informed us that the North Carolinians had very graciously bought our lunch! Southern hospitality beyond the call, but it was greatly appreciated and we enjoyed more conversation with them on the beach afterward.
Back to the Settling Point Harbor in the late afternoon, we found Sila had dragged and was entwined with a catamaran in the anchorage! Uh oh.... Steve and Deb on Alternate Latitude, a lovely charter boat, were profoundly calm and gracious as we untangled the boats and sorted out the chaos. We also appreciated the help from unknown cruisers who tied the boats together neatly with fenders as none of us were aboard when it initially happened.
What happened? We had set the anchor on 3/4 power reverse as we always do in firm sand and then Sila had sat unmoving for 36 hours before we left the boat. All of this was without a peep from the anchor alarm, which we typically set to alert us when we move more than 2/100th of a nautical mile. So initially we were baffled about why our anchor dragged but on reflection, my error became apparent.
We had anchored in a very shallow spot, about1.8 meters deep and were on 7.6 meters of chain. Subtracting the 1.2 meters of height for the bow roller off the water this left us with 6.6 meters of chain out, a bit over 3:1 scope. Three to one scope isn't ideal but should be sufficient for a calm anchorage on an anchor that has been firmly set... But... And there is always a but...
After we set the anchor, I always go forward and attach a snubber line. A snubber is a stretchy piece of three stand nylon line that we use to absorb the anchor load rather than lie to chain alone, which can shock load the anchor. I attach the snubber by choking up on the chain, securing the line with a rolling hitch and then veering some chain until it is loose and the snubber takes the load. This process can "use up" some chain, maybe even two meters worth if one isn't thinking about it. In deeper water with lots of chain out, the change in rode length is nominal and doesn't change the effective scope.
In very shallow water, subtracting 2 meters from the scope when I tied on the snubber and just a touch of tide, meant that we were actually on 4.4 meters of rode in 2 meters of water. So having firmly set our anchor I choked, and choked us up to 2:1 scope. This is insufficient! Sila was most likely steadily and gently lifting her anchor out of the firm sand for 36 hours until it released and we dragged our way through the harbor. Such fun to be "that guy," however the damage to Alternate Latitudes wasn't too bad and in the end it was a gentle lesson relative to what could have been.
All this was also a good example of over-confidence, aka the "familiarity error" in decision making. In the last 10 years, we have never dragged our anchor once set. On Sila we have a modern design anchor that is large for our size boat: an 82 pound Spade. As a result, we have found the anchoring even easier. Inside this great anchor and rode setup lies the seeds of over confidence in which I indulged; Lesson learned.
Also, if you are going to drag your anchor and tangle up with another boat in the harbor, I strongly recommend Steve and Deb on Alternate Latitude. I can attest that they remain calm under pressure, wear difficulties lightly, and are solution oriented when problem solving. Also their boat is well found, nice looking, comfortable, and their passengers were all having a great time aboard. All to say, any readers looking to charter on a captained boat in the Caribbean ought to take a careful look at www.usvicatamaran.com or email them directly at alternatelatitude@gmail.com. Great folks and a nice boat. We look forward to running into them again but I hope it will be with a bit more grace on our part next time. - Christopher
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