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Old 23 July 2012, 04:05   #11
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Downside of using an anchor line too thick is that in really deep water and big waves and with a strong tide running the amount of drag acting on the line doesent always let the boat ride the waves proper to the point that some boats can start getting swamped .
Best rope for anchoring or veering is nylon as is has a high loading will stretch and reduces snatching action .
Another good thing about nylon is that if anchored up and veering or backing up to something Say a sheer cliff or lee shore to pick up someone , using the high elasticity of nylon if your engine then cuts out or the prop catches a rock the stretch of the line (up to 50%before parting ) ) will pull you back out into deeper safer water .
Nylon is ideal as an anchor line or tow line for a boat but it's not suitable and can be dangerous in long lengths for pulling boats on slipways with a vehicle or tractor especially if the trailer wheels get stuck or bogged down and the wheels then suddenly break out
and yes I have seen a I ton boat suddenly fly up the slipway
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Old 23 July 2012, 09:36   #12
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Originally Posted by m chappelow View Post
Downside of using an anchor line too thick is that in really deep water and big waves and with a strong tide running the amount of drag acting on the line doesent always let the boat ride the waves proper to the point that some boats can start getting swamped .
Best rope for anchoring or veering is nylon as is has a high loading will stretch and reduces snatching action .
Another good thing about nylon is that if anchored up and veering or backing up to something Say a sheer cliff or lee shore to pick up someone , using the high elasticity of nylon if your engine then cuts out or the prop catches a rock the stretch of the line (up to 50%before parting ) ) will pull you back out into deeper safer water .
Nylon is ideal as an anchor line or tow line for a boat but it's not suitable and can be dangerous in long lengths for pulling boats on slipways with a vehicle or tractor especially if the trailer wheels get stuck or bogged down and the wheels then suddenly break out
and yes I have seen a I ton boat suddenly fly up the slipway
Nylon also looses a fair amount of its strength when wet, so needs to be a little bigger to cope with the loss of strength.

The problem of whiplash with nylon is very real, think elastic band breaking, and at the very least if you are in the way, it will sting, or worse.
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Old 23 July 2012, 11:22   #13
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The problem of whiplash with nylon is very real, think elastic band breaking, and at the very least if you are in the way, it will sting, or worse.
Not really an issue with anchoring, as the water will dampen any backlash from a sub-surface failure and the above water length isn't long enough to be a major concern, but it is definitely something to watch for when towing.

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Old 23 July 2012, 11:22   #14
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Disagree as far as the line goes. Assuming a reasonably sized nylon rode, the line should stretch as the boat surges in the swell. Use too large a line (or a low-stretch line of any size), and the boat will not generate the force to stretch the line, resulting in a lot of harsh snatch and jerk stuff as the boat rides on the hook. May or may not be really bad depending on conditions of seas and boat, but can be fairly destructive over time.

Chain, yes, bigger is better as long as it doesn't get cumbersome to the point of not wanting to deploy becuae of it.

Anchor: size ideally depends on the type, which ideally depends on the bottom structure and seas you'll be anchoring in.

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I did say Generally(even underlined it) The gear needs to be relatively matched, i.e. there's no point putting a 2kg folding grapnel on the end of a 20mm dia rope. Neither is there any point putting a 20kg plough on the end of a 6mm bootlace. I had credited the OP with some common sense. The chain plays as large a part in acting as a shock absorber as the rope does, if not more so.
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Old 23 July 2012, 11:33   #15
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The chain plays as large a part in acting as a shock absorber as the rope does, if not more so.
+1

I just had a look on Youtube to see if there is a nice animation of a chain laying on the seabed, showing the anchor as being nothing more than the machine hat holds the end steady. Having not found one, I might see if Brains' underwater camera is available to film some footage of just that.
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