Tuesday, December 22, 2009

Bahamian Moor

The boys and I motored around Nantucket Harbor looking for an anchoring hole. No dice, and finally the harbormaster directed us to the northern edge of the anchorage, a little southwest of First Point. There was open water there, but there was also about three knots of current.

The bottom is hard sand, good holding bottom. But I knew when the current reversed the anchor would likely trip and maybe it wouldn't reset.

A Bahamian moor was the obvious answer. We lowered the anchor, paid out the appropriate scope, settled back in the current and made sure the anchor was set. Then we paid out the same amount of rode again, lowered the second anchor, and pulled ourselves back up to the midpoint between the two anchors.

A few hours later the current had reversed and we lay to the second anchor. The first anchor remained dug in and we didn't have to worry about whether it, or the second anchor, would trip out as every six hours the current reversed.

Our swinging radius was much reduced, which was a good thing so long as the radius more or less matched that of nearby boats. We used a Bahamian moor once in a narrow tidal river where not only was there a reversing current, if we swung much we'd probably ground on nearby flats.

I take both anchors to the bow. I doubt there are many circumstances in which it would be appropriate to secure one anchor to the stern and another to the bow.

If you lay to two anchors for several days and the winds shifts around the compass your anchor lines could twist. Some books talk about joining both rodes, for example with bowlines secured to a big shackle and swivel, and laying to a single line, to eliminate this twisting. Sounds complicated but I could see how this could be correct sometimes.

I used to worry when anchoring this way that at slack water the rodes might hang up on the keel or the prop, but nylon sinks and I believe it hangs below the keel until the current sorts itself out. Perhaps if I had a fin keel with a separate rudder I would weight the rodes 30 or so feet out from the boat so they hung straight down when under no strain. I carry a few short lengths of chain for that sort of thing.

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