Poor Seamanship - Anchoring

[Hud3]

Originally Posted by Dockhead

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?

That was the anchorage where I kept my boat for the two years it was here on Nevis. According to the locals, it was supposed to be very safe from swells, unless they came from the west or southwest, so I always watched the weather for those. These swells came from the north.

Storms in the Atlantic, way up north off the Virginia Capes and New Jersey, sometimes send swells down here, 1400 to 1500 nautical miles away. The swells are sometimes very noticeable, but nothing like what you see in that photo. That was in March, 2007. That time, a cold front spawned an extremely intense storm, with winds in the 90-100 kt range. It took three days for the swells it generated to arrive, and they arrived overnight. So when I went down to look at the boat in the morning, she was having the time of her life surfing up and over 15'-16' rollers.

Thank goodness she held her mooring. A local fisherman wasn't so lucky. He didn't use any chafe protection at all. He had an anchor out, along with the 1-1/4" mooring pennant run through a chock to a cleat on his bow. His boat took out a smaller pirogue as it washed up on the rocks.

[Pelagic]

Originally Posted by Dockhead

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.

This is the comment that confuses me a bit…..

To my way of thinking …a snubber applied in bridle fashion (as I show here on Stargazer) has the practical application in lowering the angle of pull on the chain’s catenary, removes chain noise being transmitted thru the hull and the bridal keeps the vessel from sheering too much in gusty bullet type winds.

I have never considered it my primary solution for securing the anchor… To me…it is more a comfort … rather than a security thing.

If I find myself caught in an exposed anchorage as Dockhead did, I would actually remove my snubber and rely on my primary chain stopper to maintain quick control over my ground tackle.

There are many types of clamps/ stoppers...as you can see here:

Chain-stoppers - All companies

After all, the breaking strain on your chain should far exceed the shock loads of a lively night at anchor and if you needed to pay out or haul in and leave in the middle of the night…. There are no complications.

I also strongly recommend you maintain that weak link in your chain locker at the bitter end.

Hopefully it will never happen, but for example.... if you had to quickly let go your ground tackle completely to escape a barge or ship quickly drifting down upon you at anchor…. Getting volunteers to go into the chain locker with a knife or wrench, with seconds to spare... might prove difficult.

It has been part of survey recommendations for years and there are good reasons borne from actual events.

Thanks for sharing your night.... many of us have been there..

[btrayfors]

Dockhead,

When you go to fit a chain stopper, beware of sizing issues.

I went with a Lewmar s/s stopper...deluxe model in 3/8" size...and what should have been a 2-hour install turned into a 3-day nightmare over a 2-week period.

Long story short, the 3/8" stopper was too small for 3/8" chain, and Lewmar to their credit admitted that their dimensions to the foundry were wrong. After examining alternatives, they comp'ed me a 1/2" chain stopper for my 3/8" G40 chain, and it works quite well. It is massive, though, compared to the 3/8" model which was too small. And, of course, the mounting bolts have different spacing and are massive -- 5/8" bolts which MUST be Allen-head to fit in the recesses in the chain stopper.

Here's the finished product.



Shop carefully!

Bill

[noelex 77]

Originally Posted by Dockhead

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

Great story.
Try an avoid the temptation to go too thick on the snubber as you loose a lot of elasticity. Avoiding chafe is critical.
I have broken a few snubbers over the years and they have always gone with an enormous bang, which has woken me up. Even so I always have a chain stopper and a line with a hook through the chain for added security. After the chain I have 50 m (150 feet ) of nylon rode and that extra scope if it was let out unexpectedly could often cause problems.

[blahman]

Hey all,

Scary story indeed. Makes me wonder how my system would work out in that case.

Re: Chain safety line

I use a length of 3/4" tubular webbing to secure the end of the chain to the samson posts within the locker. It's long enough to let the chain run out to a couple feet before the anchor roller and has a pelican clip on the end of it for quick-release from the chain. If for some reason the clip doesn't work, the polyester webbing (with a breaking strength of around 4000lbs) is really easy to cut; it seems the optimal material for a safety line on the end of the rode. The samson posts are probably as strong of an object as you could ask for in a boat to make the safety line too.

Are you all suggesting that the safety line at the end of your rode should be strong enough to take all the load of anchoring for extended periods? An anchor rode who's snubber(s) has broken, and who's windlass or object to which the actual rode is made off, has also failed and allowed the rode to run out? If that is the case, I'm pretty sure my webbing would be inadequate; but what are the chances that all of my snubbers will fail, and the windlass and samson posts will get torn off the deck and/or allow the rode to run out, to the extent that one would have to rely on the safety line to hold the boat? It seems like if one ever got into the position where his road has run all the way out, he should focus more on getting out of that place? Thinking about it does make me see that my safety line may need to be upped significantly...or at least quadrupled or something.

Every time we anchor, I put a small float with our boat's name and 35' of poly rope and a boat-snap on the end of it for quickly attaching to the chain, in case we have to let the rode run out. I've always set a good snubber up, but never had additional snubber lines ready to go in case the first one fails...Time to dig out and make up some more.

~A

[FraidNot]

Hmm - a great read, thx guys. I have been using just a 6' nylon snubber with clear poly pipe over for anti-chafe. What length do people use in a blow? Seems like much longer is a good idea?
20' ??

[noelex 77]

Originally Posted by FraidNot

Hmm - a great read, thx guys. I have been using just a 6' nylon snubber with clear poly pipe over for anti-chafe. What length do people use in a blow? Seems like much longer is a good idea?
20' ??

An ideal snubber length (for strong wind) is somewhere between 10 and 15m (30 to 45 feet). The length is not critical, but too short and there is not enough stretch, too long springs the boat too far forward when the gust passes, 6 feet is defiantly too short.
If you need to let out more scope its helpful to lengthen the snubber ( to save motoring forward) and I often use some old halyard (low stretch) to do this (this lengents the snubber but does not increse the stretch).
As an alternative,if you want to let out a lot more chain, let the old snubber go to the bottom (only do this with a rolling hitch, if you use a chain hook you will loose the snubber and hook) and reattach a new 10-15m one.

With a 10m snubber you will be amazed how much it stretches in strong wind so leave a generous loop of loose chain.

Be careful in shallow coral waters that when the wind dies the snubber may chafe on the bottom and may need to shortened.

[Dockhead]

Originally Posted by blahman

Hey all,

Scary story indeed. Makes me wonder how my system would work out in that case.

Re: Chain safety line

I use a length of 3/4" tubular webbing to secure the end of the chain to the samson posts within the locker. It's long enough to let the chain run out to a couple feet before the anchor roller and has a pelican clip on the end of it for quick-release from the chain. If for some reason the clip doesn't work, the polyester webbing (with a breaking strength of around 4000lbs) is really easy to cut; it seems the optimal material for a safety line on the end of the rode. The samson posts are probably as strong of an object as you could ask for in a boat to make the safety line too.

Are you all suggesting that the safety line at the end of your rode should be strong enough to take all the load of anchoring for extended periods? An anchor rode who's snubber(s) has broken, and who's windlass or object to which the actual rode is made off, has also failed and allowed the rode to run out? If that is the case, I'm pretty sure my webbing would be inadequate; but what are the chances that all of my snubbers will fail, and the windlass and samson posts will get torn off the deck and/or allow the rode to run out, to the extent that one would have to rely on the safety line to hold the boat? It seems like if one ever got into the position where his road has run all the way out, he should focus more on getting out of that place? Thinking about it does make me see that my safety line may need to be upped significantly...or at least quadrupled or something.

Every time we anchor, I put a small float with our boat's name and 35' of poly rope and a boat-snap on the end of it for quickly attaching to the chain, in case we have to let the rode run out. I've always set a good snubber up, but never had additional snubber lines ready to go in case the first one fails...Time to dig out and make up some more.

~A

One thing I notice in this post is consideration of the windlass as a structural element of your ground tackle. It is not. I know relatively little about anchoring, but if I know anything, it is not to consider your windlass in this role at all. If your chain is on your windlass, that does not mean that it is "made off" to it.

Certainly, you need to make off the chain in some way before the windlass. I think more or less all of us do this. My previous boat had a chain stopper for this purpose. I have tied a dockline to the chain between the windlass and the bow roller with a rolling hitch, then made off the dockline to a bow cleat. Recently I bought a chain hook with a short strop, and use that. I in this particular case, it was the chain hook and strop which saved my bacon.

How the bitter end is attached in the chain locker is the third line of defense.

[Bash]

Originally Posted by Dockhead

Very interesting idea!

Can you describe your "double snubber"? In what way is it "double"?

I'm talking about an API bridle plate. Maxingout has a photo of his in the second post of this thread: http://www.cruisersforum.com/forums/...wls-27845.html

[blahman]

Originally Posted by Dockhead

If your chain is on your windlass, that does not mean that it is "made off" to it.

Sorry to have been unclear; I realize that the wildcat, even with safety pawl engaged, is not to be used as a to permanently make off the rode. I have a line which I rolling hitch to the rode after the windlass, but before the roller to act as a chain stopper and as a backup to the snubber. Of course, if I'm just anchoring for lunch and conditions permit, I'll just use the safety pawl on the windlass - I do think its adequate for short, supervised use.

I was taught to leave the chain on the wildcat all the time, even when anchored, which makes sense to me. It allows controlled payout and retrieval. Thus, it definitely is structural to my anchoring system; if my snubber and chain stopper both fail, the rode will fetch up against the windlass' brake. The only option would be to leave the windlass' brake and safety pawl disengaged or to pull the rode off the windlass altogether, which I do not like to do; only when hauling back.


As for the safety line in the case of a full pay-out, it seems whatever is there should be strong enough to take the load of the rode, but only for a short enough period for additional pendants, bridals, snubbers, lizards and Egyptian snake dances to be rigged on the rode to ensure it doesn't let go. But those steps should be taken, if at all possible, before the rode gets to that point.

~A

[Talbot]

Originally Posted by MarkJ

?

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

12mm far too small for that use. In any case your reference is to polyester not nylon. I really recommend a study of the property of the different ropes. nylon is used in this area because of the stretchiness.. However the polyester octoplait is better for berthing hawsers as too much stretchiness here is not so good.

[Dockhead]

Originally Posted by blahman

Sorry to have been unclear; I realize that the wildcat, even with safety pawl engaged, is not to be used as a to permanently make off the rode. I have a line which I rolling hitch to the rode after the windlass, but before the roller to act as a chain stopper and as a backup to the snubber. Of course, if I'm just anchoring for lunch and conditions permit, I'll just use the safety pawl on the windlass - I do think its adequate for short, supervised use.

I was taught to leave the chain on the wildcat all the time, even when anchored, which makes sense to me. It allows controlled payout and retrieval. Thus, it definitely is structural to my anchoring system; if my snubber and chain stopper both fail, the rode will fetch up against the windlass' brake. The only option would be to leave the windlass' brake and safety pawl disengaged or to pull the rode off the windlass altogether, which I do not like to do; only when hauling back.

As for the safety line in the case of a full pay-out, it seems whatever is there should be strong enough to take the load of the rode, but only for a short enough period for additional pendants, bridals, snubbers, lizards and Egyptian snake dances to be rigged on the rode to ensure it doesn't let go. But those steps should be taken, if at all possible, before the rode gets to that point.

~A

Ah, I see. I do more or less the same. I used to rolling hitch a heavy dockline onto the chain between the windlass and the bow roller, to take any load off the windlass. Now I have a chain hook and strop, which is somewhat easier to rig. I always leave the chain on the gypsy; there is hardly any way on my boat to take it off. But I try to avoid any situation where the windlass might get a load. One advantage of the hook & strop is that it is so simple to rig that you don't mind rigging it even if you are anchored for a half hour for lunch.

As to the last line of defense -- how the bitter end of the chain is made off in the chain locker -- I would like for it to be strong enough to hold the boat for a long time under a lot of load. I am not sure that I would necessarily be aware that things had gotten that far. The other night I was totally unaware that the snubber had broken -- aft cabin and quiet boat.

[Dockhead]

Originally Posted by Tallbot

12mm far too small for that use. In any case your reference is to polyester not nylon. I really recommend a study of the property of the different ropes. nylon is used in this area because of the stretchiness.. However the polyester octoplait is better for berthing hawsers as too much stretchiness here is not so good.

There is also nylon octoplait, which I think is what the person who brought this up had in mind. Sometimes called "anchorplait". Sounds like a great idea for this use.

[MarkJ]

Originally Posted by Tallbot

In any case your reference is to polyester not nylon. .

ooops!!!!!!

12mm White Multiplait Nylon Mooring Anchor Rope Per Metre
Details
12mm white multiplait nylon rope. The 8 strand construction allows the rope to be very flexible, easily spliceable to chain, yet with a high strength and stretch. No need to coil into chain lockers, this rope runs well following chain. Breaking Load - 3000kg
List Price: £1.95
Price: £1.49 (£1.75 Inc. VAT)
14mm White Multiplait Nylon Mooring Anchor Rope Per Metre
Details
14mm white multiplait nylon rope. The 8 strand construction allows the rope to be very flexible, easily spliceable to chain, yet with a high strength and stretch. No need to coil into chain lockers, this rope runs well following chain. Breaking Load - 3800kg
List Price: £2.20
Price: £1.65 (£1.94 Inc. VAT)
16mm White Multiplait Nylon Mooring Anchor Rope Per Metre
Details
16mm white multiplait nylon rope. The 8 strand construction allows the rope to be very flexible, easily spliceable to chain, yet with a high strength and stretch. No need to coil into chain lockers, this rope runs well following chain. Breaking Load - 5300kg

OK.

Now we had a thread somehwere to determain what breaking strength we need?

Its all too much for me so early in the morning - but I want a second snubber soon..

[Dockhead]

Originally Posted by FraidNot

Hmm - a great read, thx guys. I have been using just a 6' nylon snubber with clear poly pipe over for anti-chafe. What length do people use in a blow? Seems like much longer is a good idea?
20' ??

To me that seems awfully short for any purpose or conditions. I have always used about 6 meters -- 20 feet. Judging by some of the comments here, even that may be too short for some conditions.

I think it also depends on how heavy the line is. A lighter line will stretch more and require less length, but then again, will not stand up to heavier conditions.

I am thinking about ordering two snubbers --

One lighter, shorter one -- say 16 mil and 6 meters. For calm conditions.

And one heavier, longer one -- say 20 mil and 10 or 15 meters. For harsher conditions.

They say go down one size from your regular anchor rode size, for a snubber.

The Rocna Knowledge Base (one of the best resources in my opinion) says this:

"Rope used as a dedicated snubber should be sized according to the conditions and the vessel. In general a minimum of 10 m (30') should be employed, or a length of half the LOA of the vessel, whichever is longer. A shorter snubber (depending on the rope diameter) does little with regard to shock absorption, but it will serve the purpose of stopping chain rumble and roller noise."

Snubbers (Rocna Knowledge Base)


Sounds like adding a rubber buffer like this:

Anchors and Chain - Heavy Duty Snubbers

is also a very good idea.