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Old 01-11-2010, 06:53   #31
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No, I was taking the photo.

And biting my fingernails. All was well, though, only a plastic cup or two had rolled onto the cabin sole. Everything else snug as a bug.
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Old 01-11-2010, 06:57   #32
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Hi Mate, Thanks for the response. If I may reply within your post.

Quote:
Originally Posted by Dockhead View Post
That's a great setup. Not practical for my case -- I'm just not going to start drilling holes in my stem -- but if you've got it then you've got a perfect setup.

My roller sits out about 20cm from the stem and I drilled a hole about 15cm out.

Another advantage you have is that the vector of force from your snubber will be applied lower down. A lot of stress resulted -- I was feeling it and thinking about it all night -- from the fact that the chain pulling tight against the snubber tries to pull the bow down, and maybe just at the moment when the bow is being lifted by a swell.

Yeah this has to be a dampening effect - and why I use the longer snub to try and keep the chain low, deep in the water.

I've had an idea to improve chafe resistance of my snubber, short of making swiss cheese out of my stem:

Make a bridle of stainless steel cable with two loops to slip over either bow cleat.

Steel cable goes over the bronze bow roller (the spare one) and terminates in an eye and a shackle. The snubber, a heavy three-strand nylon job, is shackled to that via an eye splice. And is rolling-hitched to the chain six meters or so further down.

That way, the nylon doesn't touch anything, and all the chafe is taken care of by steel cable running smoothly over the bronze bow roller.

How about that?
SOunds great - go for it. Would the stainless still chafe bronze? Many people like twin snubs as a kind of 'flopper stopper' alternative as well as being a snub.

Can you shackle the snub at the roller? Weld a loop underneath to take the load?

My main rationale was to eliminate any movement over the roller - (chafe and noise) The short one is a 3 strand 24 mm nylon line. The longer snub is plaited line about 25mm.

My 'experiment' is always up for improvement so I would love to hear how you go.

You must have had a sleepless night that night.
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Old 01-11-2010, 07:05   #33
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I notice silence from my part of the world on this excellent post so I will chime in. First-- Good On You for deciding to leave the dock in the first place.
Second- You rigged a snubber and a backup and the boat stayed on the hook. Nothing wrong with that.

You have a 25 ton yacht that just needs a bigger snubber that can stand more snatch load. Perhaps if it was a bit longer it would have had more stretch and not parted?

I guess I am a nervous nelly on the hook but I would not have been able to sleep under those conditions and would have been up all night fussing and drinking coffee.
Thank you for an excellent post.

Todd
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Old 01-11-2010, 07:15   #34
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I don't think I could stand the grinding of the steel cable against the bronze--wouldn't it be like sitting in a dentist's chair for hours?

Simple chafe protection works pretty well with nylon or polyester line. My boat rode out these breaking swells for 10-12 hours with 5/8" double braid polyester wrapped in an old towel where it went over the anchor roller. I had a second one rigged in reserve, a bit slack, but the first held just fine. I was on a mooring, but it would seem that the same would apply to a snubber on an anchor chain.
Good God Hud -- that is something to be anchored in. I'm afraid that would rip your bow roller right off. It's inspiring that your set up survived that.


A steel cable running over a bronze bow roller shouldn't grind -- the roller will roll. I would think it would be nearly silent if the roller is well lubricated (and I recently greased mine).
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Old 01-11-2010, 07:18   #35
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Originally Posted by IdoraKeeper View Post
I notice silence from my part of the world on this excellent post so I will chime in. First-- Good On You for deciding to leave the dock in the first place.
Second- You rigged a snubber and a backup and the boat stayed on the hook. Nothing wrong with that.

You have a 25 ton yacht that just needs a bigger snubber that can stand more snatch load. Perhaps if it was a bit longer it would have had more stretch and not parted?

I guess I am a nervous nelly on the hook but I would not have been able to sleep under those conditions and would have been up all night fussing and drinking coffee.
Thank you for an excellent post.

Todd
Thanks. I did NOT sleep all night. I was awake listening and brooding. At one point the boat was rolling so violently that I had to get rid of a glass of water next to my bunk for fear it would be slung around the cabin. The next morning you could see how the swell was breaking just beyond where we were anchored -- surf's up!

Well, yes, certainly, I need a bigger (and newer) snubber. And I need to avoid anchoring in conditions like that. I'll know better next time. And I need some really solid backup to prevent a runaway chain if all else fails.

Cheers, Dockhead
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Old 01-11-2010, 07:22   #36
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Originally Posted by rusky View Post
Hi Mate, Thanks for the response. If I may reply within your post.



SOunds great - go for it. Would the stainless still chafe bronze? Many people like twin snubs as a kind of 'flopper stopper' alternative as well as being a snub.

Can you shackle the snub at the roller? Weld a loop underneath to take the load?

My main rationale was to eliminate any movement over the roller - (chafe and noise) The short one is a 3 strand 24 mm nylon line. The longer snub is plaited line about 25mm.

My 'experiment' is always up for improvement so I would love to hear how you go.

You must have had a sleepless night that night.
Oh, I had not appreciated that your hard point is in your roller. Hmm. Have to think about that when I'm next near the boat.

I would not think that a stainless wire rope would chafe on a soft bronze bow roller, which is greased and rolling as the cable runs over it.

Yes, the night was entirely sleepless!
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Old 01-11-2010, 07:24   #37
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No, I was taking the photo.

And biting my fingernails. All was well, though, only a plastic cup or two had rolled onto the cabin sole. Everything else snug as a bug.
How did that happen? I would love to hear the story. Was it a storm from an unusual direction, in an anchorage where you usually have shelter?
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Old 01-11-2010, 08:20   #38
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I will try to be brief.

The snubber is meant to give some give so that when the chain comes up "bar tight" it does not grab the anchor out of the ground.

You said that your snubber was attached to the two bow cleats. Question? How long was the snubbing line?

My boat is 44000 lbs. My snubber goes back to the midship cleats, about 35 feet or more. I have ridden through a cat one hurricane on this with 3/8th BBB chain and a 110 lb claw anchor in good holding. However during the storm I noticed that at times the snubber (3/4 inch three ply nylon) was stretching a good three feet plus. To stop chafe over the roller I put the hot end of the line through about 12 feet of clear plastic hose. The hose usually last about two years.

A friend with a 65 foot heavy steel boat uses 60 feet of 1" three ply nylon for a snubber
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Old 01-11-2010, 08:26   #39
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12mm 3-strand nylon.

rope material was correct - stretch is essential in this situation in order to cope with the snatch loads.

size was much too small to be able to cope with snatch loads anyway.

3 strand is very much NOT the right stuff for this application. high stretch and then tension release leads to a problem with the rope called (in UK) knuckling where one strand twists over itslef and then stops the rest returning to normal rope shape. When the next load comes on the rope, the knuckle is a major weak point as it puts all the weight onto that one strand. The result is rope breakage.

The solution is to use octoplait.

This also an important issue for parachute anchors or any other form of anchoring. 3 strand is cheap, but yesterday's technology. get octoplait. As a benefit is is much easier to handle, and MUCH MUCH easier to coil.
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Old 01-11-2010, 08:48   #40
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The solution is to use octoplait.

.
Quote:
Description Octoplait polyester rope.
Designed for good looks on big yachts. High stretching capacity due to its specific structure. Good traction, abrasion and UV resistance. Flexible and easy to splice.
Ø Break load
10 mm 2000 kg
12 mm 2800 kg
14 mm 3800 kg
is 12 mm enough?
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Old 01-11-2010, 09:02   #41
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there are situations when an undersized snubber is desirable, and situations where you need something that will stand up to a beating. I use a small snubber--1/2" line with a single chain hook--95% of the time because I want the snubber to stretch. I also have a double snubber with 3/4" line that is there for situations such as the one in which Dockhead found himself.

I consider the small snubber a disposable piece of gear, something I figure won't last any longer than a set of jib sheets.
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Old 01-11-2010, 09:04   #42
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Re: attaching an all-chain rode to a bulkhead.

The way I learned things, it's a good idea to have a short loop of nylon between the chain and the bulkhead. That way, if you ever need to cut and run, you've got something easy to cut.
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Old 01-11-2010, 10:40   #43
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You said that your snubber was attached to the two bow cleats. Question? How long was the snubbing line?
6 meters -- about 20 feet.
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Old 01-11-2010, 10:44   #44
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there are situations when an undersized snubber is desirable, and situations where you need something that will stand up to a beating. I use a small snubber--1/2" line with a single chain hook--95% of the time because I want the snubber to stretch. I also have a double snubber with 3/4" line that is there for situations such as the one in which Dockhead found himself.

I consider the small snubber a disposable piece of gear, something I figure won't last any longer than a set of jib sheets.
Very interesting idea!

Can you describe your "double snubber"? In what way is it "double"?
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Old 01-11-2010, 10:47   #45
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Re: attaching an all-chain rode to a bulkhead.

The way I learned things, it's a good idea to have a short loop of nylon between the chain and the bulkhead. That way, if you ever need to cut and run, you've got something easy to cut.
Naturally.

The boat came that way. There is a stainless ring attached to the bulkhead with a through-bolt, to which is attached a nylon line fastened to the bitter end of the chain.

Another thing I need to do -- on the endless list of things to do -- is hang a knife next to it.

But the problem is different -- what if your chain runs away because your snubber broke and other chain-stopping measures failed. That little nylon line will snap. I think about creating a stronger point of attachment and using some really strong Dyneema loops.

It would really suck to wake up on the beach, because your snubber failed and your chain ran out. Nearly happened to me yesterday.
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