What size for snubber?

[Jim Cate]

Originally Posted by Andrew Troup

Jim

Vibration from either the rode or the deck could do the trick to defeat the metal-to-metal contact at the loaded tooth, and get things rolling.

The vibration would probably need a significant component at a critical frequency to get the thing resonating.

I'm even more amazed than I was if the wormwheel does not have rolling element bearings - are you certain they're plain bronze?

Yep, having just rebuilt my vwc1500, they are indeed plain bronze.

Jim

[Jim Cate]

Originally Posted by noelex 77

I am very surprised as well.
I understood the worm drive was self locking and could not be reversed. Presumably this applies at least up to the rated load of the winch. There is no other locking mechanism on most designs.

Are you sure it was not just the clutch that was allowing the gypsy to spin?

Yes, quite sure. The whining noise that I mentioned in the first post relative to this event was the motor being turned (fairly fast) by the exiting chain.

I can't guess at the load being applied, other than to say it was a lot!

An interesting experience and an interesting discussion...

Cheers,

Jim

[Mattyb]

After reading through this thread I have decided its time I better get myself some nylon rope not just for a snubber but I am living in north west Australia and am right in the cyclone area. Going by what has been said an the ratings I have seen on the rope I thought 3 strand nylon at 12mm would be best as an anchor snubber and also to tie off to the mangroves when a cyclone hits but after having seen it in the shop now she looks mighty thin!!! I have a 36ft ferro around the 13-14 tonne mark. Any thoughts or experience with tying off to mangroves? I thought this thread would be the appropriate spot to put this but if not I can make a new thread. Cheers

[Andrew Troup]

Thanks for the confirmation, Jim, that's sobering.

Originally Posted by Mattyb

...I have decided its time I better get myself some nylon rope not just for a snubber but I am living in north west Australia and am right in the cyclone area. Going by what has been said an the ratings I have seen on the rope I thought 3 strand nylon at 12mm would be best as an anchor snubber and also to tie off to the mangroves when a cyclone hits but after having seen it in the shop now she looks mighty thin!!! I have a 36ft ferro around the 13-14 tonne mark. Any thoughts or experience with tying off to mangroves? ....

Ideally you want to use a number of light lines, 12mm 3 strand nylon sounds good to me. You wouldn't want to be putting more strain on the individual mangroves than that line would cope with. Think of a spider's web: the multiple strands spread the load due to their elasticity. (In this case, there'll be some elasticity in the trees themselves, but more can only be a good thing)

I was following a well-built fellow sailor through the forest on the windward side of Niue once when he came to an abrupt halt, much like a Navy jet making a tailhook landing on a carrier.

We were so busy looking at the multitude of amazing spiders' webs in every direction and of every conceivable design, that he'd failed to see a spider's web across our track.

The web consisted of many many thick strands (by spider web standards) ... mostly unidirectional.... between two stout trees.

We looked around nervously to see what sort of spider could weave such a prodigious web.

Among the shadowy roots of a nearby coconut tree we spied a pair of eyes sizing us up. What was unsettling beyond my powers of description was the distance between those eyes.....


To cut a long story short, it turned out to be a decent sized coconut crab that belonged to the eyes, but presumably not to the web. Not to say he wasn't above having first dibs on any catch, though ...

[carstenb]

I don't have anywhere near the amount of anchoring experience that most of you here do. Certainly not in the adverse conditions you are referring to. I do like Evans use of a climbing rope. These are very elastic and very strong. My boat is a 40 ft weighing in at say 11 tons (metric) fully loaded. I have a 23 kilo Bruce and plan to buy a 30 kg Rocna before setting out on RTW. 5/8 chain, 100 meters of it.

Here's the question: If I assume that the snubber will stretch approximately 25% and I'm in say 10 meters of water, using 8:1 scope. Then a 20 meter snubber? And a 5 meter loop of chain? Let's also assume I tie off each end of the snubber to my forward cleats, thereby establishing a bridle, so now the total length of the snubber is 40 meters (although still only 5 meters of stretch??). For the sake of argument, I will have adequate chafe protection.

What size number rope? Is the above a sound proposition? What, if any modifications should be made?

[Dockhead]

I am glad some of you have had good experiences with your windlasses holding up to anchoring loads. It's a merely theoretical question for me because my windlass, a Lewmar Ocean 3, has a clutch which lets go under any kind of snatch load, protecting the windlass, I guess, which is probably not as robust as some others. But in any case, I would never let any windlass take those loads -- if the snubber is broken, the snatch loads transmitted through a heavy chain would break anything, I guess, including a bow roller or a cleat. A windlass, any windlass, is an awfully expensive and awfully fragile cleat, like using binoculars as a hammer for driving nails, as far as I'm concerned.

As to snubbers taking loads of windlasses -- again, if they are sized properly for snubbing, they will not be strong enough to belay the chain. If they are sized to be as strong as the rest of the ground tackle, they won't snub. I really think everyone needs a separate means of belaying the chain ahead of the windlass. And a means as strong as the rest of the ground tackle -- otherwise, it will be the weak link and all the rest of the strength of your ground tackle is useless.

Chain hooks, strops, knots for attaching the snubber is a matter of taste and preference. I don't myself know why anyone makes it complicated. The rolling hitch used by most cruisers works wonderfully well -- molds the snubber to the chain -- the rolling hitch actually works better on chain than it does on smooth objects. I have never heard of one untying or coming loose, and the rolling hitch is a snap to tie or untie. There is no practical limit, as far as I can tell, to the size of the rope you can tie on to your chain using a rolling hitch -- works equally well with large and small lines. For what it's worth, that's my preference!

[savoir]

Originally Posted by carstenb

I don't have anywhere near the amount of anchoring experience that most of you here do. Certainly not in the adverse conditions you are referring to. I do like Evans use of a climbing rope. These are very elastic and very strong. My boat is a 40 ft weighing in at say 11 tons (metric) fully loaded. I have a 23 kilo Bruce and plan to buy a 30 kg Rocna before setting out on RTW. 5/8 chain, 100 meters of it.

Here's the question: If I assume that the snubber will stretch approximately 25% and I'm in say 10 meters of water, using 8:1 scope. Then a 20 meter snubber? And a 5 meter loop of chain? Let's also assume I tie off each end of the snubber to my forward cleats, thereby establishing a bridle, so now the total length of the snubber is 40 meters (although still only 5 meters of stretch??). For the sake of argument, I will have adequate chafe protection.

What size number rope? Is the above a sound proposition? What, if any modifications should be made?

5/8" chain ? ? ? WOW ! Your boat would be perfectly happy with 5/16" . . . . . so would your wallet.

[carstenb]

Yeah, I know. But it came with the boat. No reason to change. It is a bit heavy up front, but I can live with it

[Dockhead]

Originally Posted by carstenb

Yeah, I know. But it came with the boat. No reason to change. It is a bit heavy up front, but I can live with it

100 meters of 5/8" chain? 16mm? Are you sure?!?! That would weigh 600 kilos and take up more space than I have ever seen in the bow of a 40 foot boat! It would completely screw up the trim of the boat if you could even get it on board! Surely it's not 16mm chain.

[noelex 77]

It might be my lousy knot tying ability I have experienced an occasional slip of a rolling hitch gripping the chain, of course under the most unfavourable conditions.
A Klemheist knot is better IMHO. (A Prusik has similar advantages)

The Klemheist is almost as simple and quick as a rolling hitch. It's tied with a separate line and forms a loop. This means that can use a thinner line (especially with a short length of spectra) than the snubber itself making the knot easier to handle and snug up tight. It also is always easy to untie. A rolling hitch around the chain can sometimes be difficult to loosen after it has been subject to high loads.
Give the Klemheist a try if nothing else it gives you a use for all those short rope off cuts that every cruising boat has buried in a locker

[carstenb]

Dockhead, you might be right. Let me check when I get home.

[Mantus Anchors]

I like all said by Klem, When sizing the snubber you want to make sure that the bridle snubber absorb the shock load that comes from gusts and waves.... Also the longer the bridle the better catenary effect bc your chain is lowered and initial load goes into lifting the chain rather than jerking the anchor....
For strength you would want at least 3/4 inch line, 3 strand nylon is a good choice because it has elasticity/stretch.....
And how long?: if you want to absorb the shock of a 3-4 foot wave I would use at least 30 feet. 3 Strand Nylon has 8% stretch at 10% off Ultimate Tensile Strength Load. In addition some of the shock absorbtion will come from the catenary effect since chain is lowered with your snubber.
I hope this helps... I know that I can't promote here but I think its fair to let you know you might be interested in a locking chain Hook.... It will make anchoring just a little bit easier...

[Hudson Force]

Great advice above from GregKutsen, but many are going to do best with different snubber arrangements according to their cruising areas and choices.

Originally Posted by GregKutsen

.......... if you want to absorb the shock of a 3-4 foot wave I would use at least 30 feet..............

Over the last forty years I've anchored out in hundreds of locations on the US East Coast & Bahamas as long as three months in one location and at times with up to a category III hurricane, a couple cat I's and a few tropical storms. I've never dealt with 3-4 foot waves! I am quick to admit to being a conservative "cockpit potato" cruiser and very atuned to the weather and making good anchorage choices. If the wind is piping up; then, I'm in a place with little fetch! I have a bridle arranged pair of three-strand 5/8" 12' snubbers on a chain hook that suits the manner in which I anchor. When I've been anchored in hurricane force winds, always in a researchd hurricane hole, I arrange a series of back up snubbers that will take the strain if the primary fails. I can remember being tucked into a small place around a couple of turns and up a channel inwith 110 kt winds overhead and 6 inch wavelets on my bow.

[jcapo]

Originally Posted by noelex 77

It might be my lousy knot tying ability I have experienced an occasional slip of a rolling hitch gripping the chain, of course under the most unfavourable conditions.
A Klemheist knot is better IMHO. (A Prusik has similar advantages)

Same here. Rolling hitches have come undone at the worst times. I switched to using a prusik and never looked back.

John

[stevensuf]

Also with rolling hitches, taking them off, if conditions turn to the worst can be a difficult thing to do, My snubber consists of 25m of 14mm 3 strand nylon, with a thimble braided on the end and a chain hook attached to the thimble, the chain hook has never came off and is very easy to remove quickly when required.