8mm Anchor chain?
- Thread starter Niander
- Start date
Storyline
Well-Known Member
Maybe that statement is true on the south coast but it is not applicable in Scotland. This summer was the first in maybe 5 years when we did not have at least one gale with a period of a few hours of >35kn winds. There are two particular problems, a lot of low lying islands and also steep mountains that can cause katabatic winds. Do take your point about the dangers with heavy tackle but in a way that means you tend to be more careful and think more before doing anything. In my experience accidents tend to happen when you are not concentrating. I think our sailing would be compromised if we carried lighter ground tackle than we have now......
I'd humbly submit that most cruisers will never experience winds, at anchor, above a continuous 35 knots and carrying heavier tackle than that needed to cope with those conditions is likely to cause more injury, (back, fingers, hands, feet) than safety AND, in many cases, cripple the vessel so equipped.
Just a point of view...
vyv_cox
Well-Known Member
The welds in the 1.5 metre length of that particular chain all had the same appearance. Instead of a typical 3-4 mm length of increased diameter the welds looked like two trumpet-like belled ends back to back. In my later testing some welds failed transverse to the wire, whereas other chain failed in a very ductile manner at the contact with the next link. Although the failure loads were similar I instinctively prefer the latter.
None of the chain I tested was marked in any way. Most of it was Chinese made, although imported by UK chainmakers. Two or three were European made but not Maggi.
Most of the Chinese chain was well into Grade 40 spec. Bradney Chain told me at the time that the chain they imported was made on the newest and best machines in the world, German made and staffed (at the time). William Hackett bought out Bradney shortly afterwards and I assume their chain is sourced from the same Chinese machines.
JumbleDuck
Well-Known Member
I don't. I wonder if the benefits of a snubber depend on the hull shape? I have a very traditional curved stem, and when the boat pulls back on the chain the bow dips down, providing effective springing through buoyancy. I have never in any situation experienced the jolting reported by some people.
doug748
Well-Known Member
That is only because you have not experienced the jolting reported by some people.
It you did, I have no doubt you would get that odd length out of the back and attach it.
I have only done it once or twice in earnest; tho I have recently devised an exciting new snubber with a rubber thing in the middle which will replace my usual tawdry length of polypropylene.
It you did, I have no doubt you would get that odd length out of the back and attach it.
I have only done it once or twice in earnest; tho I have recently devised an exciting new snubber with a rubber thing in the middle which will replace my usual tawdry length of polypropylene.
vyv_cox
Well-Known Member
As I posted some time ago in this long and interesting thread, the strongest jolting occurs due to fetching up at the end of each yaw. It maybe that your deep forefoot resists yawing more, although mine is nowhere near as shallow as some more modern, flatter hulls. I can watch my snubber stretching to a considerable extent, maybe 30 cm in about 5 metres deployed. It's 11 mm braid on braid nylon.
oldbilbo
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NormanS
Well-Known Member
+1.
In fact, I think the only F10 on the Inshore Forecast, when we were sailing, was at the beginning of October, but with plenty of warning, we made sure that we were in a place where we knew there was good holding.
JumbleDuck
Well-Known Member
Well yes, that's my point, really. Even in bouncy and windy conditions my boat doesn't seem to jolt, so I don't need to take precautions against it. As well as the bow shape it may be that as a relatively heavy displacement (26' and 4 tons, according to the crane) long keeler there may be a bit more inertia so she doesn't accelerate in either direction as much as a lighter boat would when waves pass. Noting Vyv's later point, she doesn't yaw around much either.
As an example, I was waiting for a tide at Isle of Whithorn in the summer when the wind went round to the south, bringing nasty waves with it. Although the old girl was bucking and plunging, there was no jolting and no yawing either. The chain wasn't constantly taut, by the way ... I don't have a windlass but pulling it in by hand was fine if I timed my pulls to the slackenings.
To sum up: some of us don't use rope with chain because some of us have never experienced a need for it.
JumbleDuck
Well-Known Member
I once spent a very interesting night in the Sound of Ulva with F12 forecast for Malin. Luckily the sound is so kinky that there were only ripples, but the chain was bar taut ... that was with 30 fathoms of the stuff out in two fathoms of water.
doug748
Well-Known Member
"To sum up: some of us don't use rope with chain because some of us have never experienced a need for it. "
Even a short length of rope will silence the rumble of the chain as the tide turns on a summer evening. My patent snubber should prove to be an even more versatile item
Even a short length of rope will silence the rumble of the chain as the tide turns on a summer evening. My patent snubber should prove to be an even more versatile item
Rubber snubbers come in a variety of forms but the ones with which I am most familiar are made by, or sold as from, a company called Forsheda and Taylor Made. They are a round 'rod' of rubber with enlarged fittings at each end. One runs a length of rope through the end fitting, wraps the rope round the flexible rod, maybe 3-4 times, and then through the fitting at the other end. Shockles (from America) have something similar.
These devices are heavy and not very cheap.
Comparing 10m of 12mm nylon with these devices and on the basis a veering yacht (10t x 1 knot) develops kinetic energy, 1,250 joules, then you would need 5 of these, medium sized, Forsheda type devices or 5 shockles to convert that kinetic energy of the yacht to potential energy in the rubber components. The one knot speed of a veering yacht is a real guess - anyone who has a better guess - even better has measured it - the information would be most welcome.
The rubber devices are very good for mooring in a marina, as acceleration is low - but not much use in a veering situation.
We have looked at whole range of 'elastic' materials and nylon wins hands down as it will stretch, depends on how it is made, upto 40% - fairly linearly - upto its failure point, measured in a few tons for 10mm/12mm and a lot more tons for 16mm/18mm, the failure point of these rubber devices is around 150kg/200kg.
An alternative to 3 strand or octaplait are the (nylon) snatch tapes used by 4x4s (and the military) to retrieve bogged vehicles. We have seen these tapes used, as a cat bridle/snubber but never tried it ourselves.
Jonathan
These devices are heavy and not very cheap.
Comparing 10m of 12mm nylon with these devices and on the basis a veering yacht (10t x 1 knot) develops kinetic energy, 1,250 joules, then you would need 5 of these, medium sized, Forsheda type devices or 5 shockles to convert that kinetic energy of the yacht to potential energy in the rubber components. The one knot speed of a veering yacht is a real guess - anyone who has a better guess - even better has measured it - the information would be most welcome.
The rubber devices are very good for mooring in a marina, as acceleration is low - but not much use in a veering situation.
We have looked at whole range of 'elastic' materials and nylon wins hands down as it will stretch, depends on how it is made, upto 40% - fairly linearly - upto its failure point, measured in a few tons for 10mm/12mm and a lot more tons for 16mm/18mm, the failure point of these rubber devices is around 150kg/200kg.
An alternative to 3 strand or octaplait are the (nylon) snatch tapes used by 4x4s (and the military) to retrieve bogged vehicles. We have seen these tapes used, as a cat bridle/snubber but never tried it ourselves.
Jonathan
Storyline
Well-Known Member
Even though we have a new gen anchor (Rocna) we have learned to consider the quality of the holding as equal importance to the amount of shelter an anchorage has when anything over a F8 is forecast. It is a pity that the Antares charts have no information on this although I believe they plan to include information about the seabed in each chartlet.
(Apols for o/t)
NormanS
Well-Known Member
No apology needed. Threads evolve. I have found that a good policy when gales are expected, is to choose a sheltered place with good holding (obviously), but in addition having relatively low ground to windward, and high ground to leeward. The wind then tends to pass harmlessly overhead. An exception to this is in the Cuilce in Loch Scavaig, where a F6 SWly outside, becomes a F8 SEly in the anchorage.
duncan99210
Well-Known Member
I've followed this thread with interest. We have an all chain rode with a Rocna anchor and have ridden out some high winds since we left UK, the worst being sustained winds in excess of 50 knots (24 hours or so) in Mallorca. The major problem we have encountered whenever we are at anchor in high winds is veering, not jerking. At the end of the pendulum swing and reversal to swing the opposite way causes the boat to rapidly move from heeling in one direction to the opposite side; no jerk, just a smooth but rapid transition.
In these sort of conditions, the chain and snubber are bar taught although frankly I have not spent much time closely observing how much the snubber stretches as the bow is not a comfortable place to be in these conditions.
If we expecting a big blow, then we will often deploy the kedge anchor at about the same distance from the boat as the bower but at about 50 - 60 degrees from it. This does nothing to stop the sheering - no worse, no better- but gives us a possibly mistaken sense of security.
In these sort of conditions, the chain and snubber are bar taught although frankly I have not spent much time closely observing how much the snubber stretches as the bow is not a comfortable place to be in these conditions.
If we expecting a big blow, then we will often deploy the kedge anchor at about the same distance from the boat as the bower but at about 50 - 60 degrees from it. This does nothing to stop the sheering - no worse, no better- but gives us a possibly mistaken sense of security.
doug748
Well-Known Member
"The major problem we have encountered whenever we are at anchor in high winds is veering, not jerking. At the end of the pendulum swing and reversal to swing the opposite way causes the boat to rapidly move from heeling in one direction to the opposite side; no jerk, just a smooth but rapid transition."
In this case I would be tempted to look at a riding sail. See this video from an very experienced man, our own, ex PIOTA:
You see his design in action at about 7.40.
A few more details here:
http://www.ybw.com/forums/showthread.php?198822-V-Twin-Riding-Sail
In this case I would be tempted to look at a riding sail. See this video from an very experienced man, our own, ex PIOTA:
You see his design in action at about 7.40.
A few more details here:
http://www.ybw.com/forums/showthread.php?198822-V-Twin-Riding-Sail
NormanS
Well-Known Member
My riding sail is very similar, except that as mine is a ketch, the riding sail has slides which fit into the track above the furled mizzen. The "double" sail doesn't flog, as there is wind in it all the time. I tried using a reefed mizzen, sheeted hard in, but there was a bit of noise when the wind filled one side, and then the other. The sail has two distinct benefits, it stops the boat sheering about, and as a consequence, it stops her from heeling over in the gusts, which is particularly important at mealtimes.
duncan99210
Well-Known Member
I hear what's been said about a riding sail and I did look at rigging one but with a split lower half to the backstay it comes into the more hassle than its worth category. In addition as liveaboards we already have too much stuff on board and adding yet more stuff isn't really an option, not for the 3 or 4 times a year when it would make a difference. To honest, I said it was a 'problem'; it isn't really, I was just trying to say that we don't get snatching and jerking, we get veering and heeling. Not a problem, you just live with it......
Niander
Well-Known Member
45 m 8 mm chain from Jimmy green[quality Italian chain] should do it
