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Old 08 August 2011, 16:19   #11
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Thanks guys..I'm taking it all in!...

But there's no way I'll get enough space to rotate round a 6:1 warp in many of the more popular coves...?

(non tidal, protected bay)
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Old 08 August 2011, 17:26   #12
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The 5:1 or 6:1 has nothing to do with rise of tide. I would encourage people to think in terms of 5 or 6 :1 times the maximum depth you expect to be anchored in allowing for any rise of tide.

As the OP says he has no rise of tide the it 5 or 6 : 1 the depth.

The reason for his amount of scope is that your anchor and chain work best with a horizontal pull across the sea bed. They are totally in effective if there is to much vertical pull. As already mentioned the wash of another boat can make this worse.
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Old 10 August 2011, 13:23   #13
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Sibs are really light, but poor ocean conditions can lift half my 4m of chain off the bottom. I can't imagine having any less chain since my boat needs to be at the surface waiting for me where I left it when I return from scuba diving. My anchor is an 8lb (3.62kg) Hooker Danforth style anchor. I have 310ft (94 meters) of anchor rope.

To connect the anchor to the boat I built a bridle that goes from the two d-rings in the front into a loop that passes thru the bow eye. From there I tied a loop into the end. The reason for the loop in the end is that in case one of the d-ring breaks loose, the other will hopefully continue to hold. Thru the loop I pass a locking carabiner, and at the length I want I create an overhand loop in the anchor line, then toss the whole thing overboard. So far it has worked well.

My anchor and line are stored in a milk crate turned sideways in the bow, that is mounted to the front wooden deck (Aluminum rear decks) with eye bolts and held down with giant zipties. It just gets fed (Dropped) down into the milk crate, which is breathable, and so far has not tangled. I do tie the end off to the milk crate and figure if I ever flip the boat the anchor will hopefully self deploy but I doubt it, since the anchor ends slip tightly into the milk crate. Also with the anchor tucked into place it never flies out of place no matter how rough the water gets.

Scope: yeah I use some. It depends on how much wind chop there is, but rarely do I use more than 3:1 and sometimes less if the conditions are benign. I often anchor in 100ft of water and carrying 600ft of rope would be ridiculous. We dive in calmer conditions not hurricanes.
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Old 10 August 2011, 14:58   #14
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... I do tie the end off to the milk crate and figure if I ever flip the boat the anchor will hopefully self deploy but I doubt it, since the anchor ends slip tightly into the milk crate...
I've always thought that was a bad idea, since a picture I saw in a book which showed a capsized dinghy being pulled under by a rising tide - but I suppose the force on the anchor would be huge to pull a SIB under...
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Old 10 August 2011, 15:29   #15
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While the lighter ground tackle is a good idea 3:1 scope isn't, think more in terms of 5 or 6 to 1.


A danford around 2,5 - 3 kilos , 10 meters of chain 4mm, and 25-30 mtrs of 6mm I think is ideal
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Old 11 August 2011, 13:42   #16
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I've always thought that was a bad idea, since a picture I saw in a book which showed a capsized dinghy being pulled under by a rising tide - but I suppose the force on the anchor would be huge to pull a SIB under...
Since we tend to operate fairly close to shore which is typically rocky cliffs with large waves crashing against them I would prefer to have my anchor hit the bottom and stop the boat from reaching shore. This would give me time to hopefully flip it back over. We also have slow tide changes that are not very large swings. Best thing to do is not to flip in the first place though.
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