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post #41 of Old 11-10-2013
pdqaltair
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Re: Caternary & Chain...

We seem to be all over and around the point here.

We are only discussing one senerio: when dragging is due to wind strong enough and consistent enough that all of the chain is well of the seabed. Testing demonstrated that this starts at ~ 15-20 knots and by the time it's blowing hard (>40kn) the chain has effectively no centenary to absorb shock. Thus, we need enough scope and an effective snubber.

The reason for making the point is that this dragging senario is particularly bad in that it is often...
* too strong for us to make any changes,
* re-anchor or move,
* if we hit shore we may loose the boat, and
* sudden. One minute the chain was helping, the next it is not.
It is also bad because most of us don't experience it often and thus don't get to practice. Practice is high-stakes.

Strategies that have worked for many years in lighter airs and in protected spots fail. They means NOTHING regarding success in stronger winds, since the rules change. The angle of the shank is up and shock absorption fails, both at the same time and with little warning. This is the point.

If you are dragging due to tide shift or in lighter winds, there are more serious problems. Lotsa chain isolates us from basic unsound anchoring practices, since it will sink in the mud and that helps. There local places I go that have terrible holding but work find if I use a lot of chain. But I know that chain means nothing when it blows hard... I will be off and drifting, so I make other plans if wind is expected.

(when asked how he reached the starting holds on a difficult rock climbing problem that clearly favored taller climbers - he was perhaps 5'5")

"Well, I just climb up to them."

by Joe Brown, English rock climber




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