Rope Rode - What Type (do you have)? What would you prefer?

[Dockhead]

Originally Posted by estarzinger

For me nylon all the way on the main rode, because if any rope goes out at all, it is usually a shortish section and I prefer it to act as a good snubber. Rarely, did I lay out much rope on that rode - I guess really only when I was backing into a shore tie and I wanted to drop my anchor way out because of the harbor configuration.

Yea, I guess I could put a nylon snubber on, but if I'm going to have rope out it seems like an unnecessary step.

For a secondary rode, I can see the argument for polyester, because usually you have enough out to create enough elasticity (similar to my argument for para-anchor rode). But idk, if given a choice I think I would still go nylon, in order to be as soft as possible on the anchor.

Dashew makes some what seem to me like pretty strong arguments against nylon rodes in this:

dashew-right-rode-2.pdf

Among other things, he says that nylon is approximately 10 times more vulnerable to chafe than polyester.

I use polyester for all my non-chain rodes, personally. I find that they give plenty of stretch, at least on my boat. I always use much more scope with rope rodes, than I do with chain, which also helps with stretch.

[thinwater]

Originally Posted by estarzinger

... For a secondary rode, I can see the argument for polyester, because usually you have enough out to create enough elasticity (similar to my argument for para-anchor rode). But idk, if given a choice I think I would still go nylon, in order to be as soft as possible on the anchor.

Just to clarify, I was discussing kedge only, as in hauling a boat that is stuck in the mud. The assumption is that waves and surge are insignificant (which certainly may not be true).

For anchors, primary or secondary, nylon makes more sense in most cases.

Dashew is a smart guy who also enjoys being a contrarian. He correctly observes that nylon has some short comings, but he falls short of making a strong argument for all cases. He states there is no scientific design basis, which is silly; myself and others have done a lot of load testing, and it follows very predictable principles. He correctly states that 2-3 times as much polyester is need to provide the same stretch, which is impractical for smaller boats in smaller harbors.

I have varied with testing (load cell) that in shallow water, all-polyester rode gives greater impact loads than all chain, because the rode is too short to stretch and there is no catenary. It is a real jackhammer, and you can prove this for yourself. In deep water, say backing 200 feet of chain, the catenary provides a great deal of shock absorption and you would only be able to measure the difference in horrendous conditions, after the wind has straightened the rode. Then, polyester can be made equivalent to nylon by deploying 2-3 times as much, which is perhaps only the difference between 250 total feet of rode and 300 feet; not a big deal. In 30 feet of water, with 200 feet of chain out and 100 feet of rope, it probably makes no practical difference in load and polyester is more durable. But I've never wanted to anchor in 30 feet. 6 feet is my average.

So for a big boat, anchoring in deep water, with a lot of chain out, polyester has real advantages. It was used on oil platforms (mostly replaced by Dyneema). But for small boats anchoring in tight places, nylon is still the better choice. Dashew brings up important issues, and I understand why it works for him, but he has not discovered a new truth for the average sailor. Most of use need either stretch or catenary, and generally a combination of both is most versitile.

[Dockhead]

Originally Posted by thinwater

Just to clarify, I was discussing kedge only, as in hauling a boat that is stuck in the mud. The assumption is that waves and surge are insignificant (which certainly may not be true).

For anchors, primary or secondary, nylon makes more sense in most cases.

Dashew is a smart guy who also enjoys being a contrarian. He correctly observes that nylon has some short comings, but he falls short of making a strong argument for all cases. He states there is no scientific design basis, which is silly; myself and others have done a lot of load testing, and it follows very predictable principles. He correctly states that 2-3 times as much polyester is need to provide the same stretch, which is impractical for smaller boats in smaller harbors.

I have varied with testing (load cell) that in shallow water, all-polyester rode gives greater impact loads than all chain, because the rode is too short to stretch and there is no catenary. It is a real jackhammer, and you can prove this for yourself. In deep water, say backing 200 feet of chain, the catenary provides a great deal of shock absorption and you would only be able to measure the difference in horrendous conditions, after the wind has straightened the rode. Then, polyester can be made equivalent to nylon by deploying 2-3 times as much, which is perhaps only the difference between 250 total feet of rode and 300 feet; not a big deal. In 30 feet of water, with 200 feet of chain out and 100 feet of rope, it probably makes no practical difference in load and polyester is more durable. But I've never wanted to anchor in 30 feet. 6 feet is my average.

So for a big boat, anchoring in deep water, with a lot of chain out, polyester has real advantages. It was used on oil platforms (mostly replaced by Dyneema). But for small boats anchoring in tight places, nylon is still the better choice. Dashew brings up important issues, and I understand why it works for him, but he has not discovered a new truth for the average sailor. Most of use need either stretch or catenary, and generally a combination of both is most versitile.

That all sounds reasonable, but I would only question the assumption that whatever you need, it must be equivalent to what you get from nylon.

I think it varies according to size of the rode and scope. My experience is different from yours because my boat is different. You anchor in 6 feet, but my DRAFT is 7 1/2! And I'm in tidal waters, with up to 13 meters of tidal range in some places. So I rarely anchor in less than 6 meters (20 feet), and 9 is probably average for me, and 20 or 30 meters not unusual. So obviously I will typically have a whole lot more rode out (up to 150 meters of rope; and I have 100 meters of 12mm chain). In this context, polyester works fine. I think Dashew's boats in his usage are similar. If you're anchoring a shallow draft cat in 2 meters of water, obviously this is a very different situation.


Incidentally, I have been experimenting with using the chain with no snubber, and have been amazed to find that the catenary doesn't even begin to come out even in quite rough conditions. The catenary of 330 kg of chain provides a remarkably strong shock absorbing force. This is very different from what I experienced on a previous boat with lighter chain. I find that I don't need a snubber at all in less than 20 or 25 knots of wind. Over 30 knots of course all bets are off, and I have broken stout snubbers in such conditions.

[thinwater]

Originally Posted by Dockhead

That all sounds reasonable, but I would only question the assumption that whatever you need, it must be equivalent to what you get from nylon.

I think it varies according to size of the rode and scope. My experience is different from yours because my boat is different. You anchor in 6 feet, but my DRAFT is 7 1/2! And I'm in tidal waters, with up to 13 meters of tidal range in some places. So I rarely anchor in less than 6 meters (20 feet), and 9 is probably average for me, and 20 or 30 meters not unusual. So obviously I will typically have a whole lot more rode out (up to 150 meters of rope; and I have 100 meters of 12mm chain). In this context, polyester works fine. I think Dashew's boats in his usage are similar. If you're anchoring a shallow draft cat in 2 meters of water, obviously this is a very different situation.


Incidentally, I have been experimenting with using the chain with no snubber, and have been amazed to find that the catenary doesn't even begin to come out even in quite rough conditions. The catenary of 330 kg of chain provides a remarkably strong shock absorbing force. This is very different from what I experienced on a previous boat with lighter chain. I find that I don't need a snubber at all in less than 20 or 25 knots of wind. Over 30 knots of course all bets are off, and I have broken stout snubbers in such conditions.

And this is why any universal answer will be sub-optimal, whether chain or nylon or rope. There is a spectrum of best answers that depends on depth, boat size, exposure, bottom type, crowding, and weather expectations.

Yes, the math says that chain will work quite well out to about 35 knots in 20 feet of water. There is no conflict there.

Over 30 knots you need a long (not stout) snubber to absorb the force, and the chafe gear and angles must be controlled. If you are breaking snubbers below 70 knots, something is wrong with the design. As a cat sailor I am completely dependent on a bridle (snubber), so failure is not an option. We kind of obsess about them. For me, 35 feet and a combined strength equal to the chain is about right.

[Dockhead]

Originally Posted by thinwater

And this is why any universal answer will be sub-optimal, whether chain or nylon or rope. There is a spectrum of best answers that depends on depth, boat size, exposure, bottom type, crowding, and weather expectations.

Yes, the math says that chain will work quite well out to about 35 knots in 20 feet of water. There is no conflict there.

Over 30 knots you need a long (not stout) snubber to absorb the force, and the chafe gear and angles must be controlled. If you are breaking snubbers below 70 knots, something is wrong with the design. As a cat sailor I am completely dependent on a bridle (snubber), so failure is not an option. We kind of obsess about them. For me, 35 feet and a combined strength equal to the chain is about right.

I will use a snubber in over 20 knots.

Over 30, I use two mega-snubbers, two 30 meter lengths of 1" three-strand nylon.

I broke a stout snubber, about 15 meters long, in a F8, winds in the 30's. The wind shifted and I lost shelter, and we were experiencing strong snatch loads from the waves. This is the kind of cyclical loading which causes many reported failures in nylon snubbers. In the absence of a better explanation, I tend to believe what Dashew wrote about it, which corresponds to my actual experience and what has happened to various people I know.

I am not really qualified to comment on your setup, as I am not a cat sailor, but I would sure as hell lock that chain off, if I were you. I don't see why this is different from what we mono sailors face. I'm not quite sure whether you said you ARE locking it off somehow or not, but if you aren't, here are some arguments that you may want to be doing so:

1. Why do you think the combined strength of the two legs of the bridle is the operative strength of the system? What about when one leg is carrying the whole load during a veer?

2. Can you be sure that you really know how much cyclical loading the nylon can stand?

3. Can you be sure you understand the dynamic loads? As I found out in my own bitter experience, they may be very different from the calculated static wind loads.

4. Can you be sure you know how much strength is lost from the nylon's being wet, etc.?

5. Can you be sure that your bridle is really immune from chafe? I think a chafe-proof bridle or snubber can be imagined -- IF you have a strong eye on the bow or something which allows you to rig it without passing over or through anything. Couldn't be done on my boat, though, without major surgery. Don't know about yours.


What if your bridle goes "bang", as has happened to so many of us? Would you be happy to just let your chain run out and your boat go onto the rocks?


This is a merely theoretical question, if you are in fact locking off that chain, as I guess you probably are.

[donradcliffe]

Originally Posted by Sunsetrider

Not convinces that all chain benefits outweigh the deficits in small to medium size boats. Lots of weight in the bow, so the only real benefit - once you get 20 or 30 feet beyond the anchor - is brute strength. It will be stretched taut under stress anyway.

I was convinced to go all chain when we pulled up the anchor at Pitcairn after 3 nights. The rode was chafed halfway through, and wouldn't have lasted another night. This was with 60 ft of chain in 35 ft of water.

[Smokeys Kitchen]

40 ft Pacific Seacraft. Nominal 12 ton displacement - closer to 13.5 loaded cruising displacement

Primary rode is 210' of 5/16 HT chain on a 25 kg Vulcan anchor
Secondary rode is 40' of 5/16 HT chain spliced to 200' of 3/4" nylon 8 plait
450 ft total rode

The two rodes are spliced together with an 'H' shaped link between the chains to allow deeper anchoring on our current cruise.

We always use a snubber. Ours is @ 50 ft - same 8 plait with a wichard chain snap shackle on the end. We snub to one of two mooring cleats, just aft of the windless. These are not the bow dockline cleats, but larger mooring cleats through bolted to an integral bulkhead

We shorten or lengthen the snubber according to current or expected conditions. We then back the snubber up with a dyneema soft shackle on the chain attached to the opposite mooring cleat with a dyneema loop. If the snubber failed, the load comes onto the dyneema loop on a different cleat and not the windless.

I also carry 2 more lengths of the 8 plait, each 100' or greater for snubbing in larger conditions or other use. Our stern anchor is a Fortress with 20' of chain and 120' of 8 plait. Our stern tie line is 300' of 1/2" Sampson MFP.

All rodes came with the boat. The extra 8 plait was obtained to match the existing ones and help ease of use for all crew. The MFP line was purchased just as a stern line for PNW use.

[thinwater]

Originally Posted by Dockhead

I will use a snubber in over 20 knots.

Over 30, I use two mega-snubbers, two 30 meter lengths of 1" three-strand nylon.

I broke a stout snubber, about 15 meters long, in a F8, winds in the 30's. The wind shifted and I lost shelter, and we were experiencing strong snatch loads from the waves. This is the kind of cyclical loading which causes many reported failures in nylon snubbers. In the absence of a better explanation, I tend to believe what Dashew wrote about it, which corresponds to my actual experience and what has happened to various people I know.

I am not really qualified to comment on your setup, as I am not a cat sailor, but I would sure as hell lock that chain off, if I were you. I don't see why this is different from what we mono sailors face. I'm not quite sure whether you said you ARE locking it off somehow or not, but if you aren't, here are some arguments that you may want to be doing so:

1. Why do you think the combined strength of the two legs of the bridle is the operative strength of the system? What about when one leg is carrying the whole load during a veer?

I do not think that. It was simply a way of stating the design basis. However, on a cat, the bridle angles is wide enough that true single leg loading is unusual. Additionally, with a snubber, the load is much less than the chain strength because the ride is much smoother than all-chain. The ABYC chain strength numbers--and good design--assumes that the chain may have to operate without a snubber. But that has very little to do with snubber loads and design.

I have two snubbers. The lighter one (BS + chain) and a heavier one (BS each leg + chain). However, the greater problem where I sail is anchor dragging in mud, so the lighter snubber is nearly always the better choice (lower forces). And there is no reason not to rig both with a few feet of slack between them. This can be done on the fly, since I generally keep a bit of tail on deck.

2. Can you be sure that you really know how much cyclical loading the nylon can stand?

Yes, there are many sources of engineering data on this. Google. ABYC rates the WLL of nylon at 9% BS (indirectly, based on relationships to test data), but this depends on the weave, chafe, and how many cycles you want to endure.

3. Can you be sure you understand the dynamic loads? As I found out in my own bitter experience, they may be very different from the calculated static wind loads.

For my boat, I have measured them in an open rodestead (10 mile fetch). Since they square very well with ABYC and because other investigators have done the same, I think so. But you are free to buy a cheap load cell and measure your own. If you are in a breaking wave zone, yeah, that is bad.

4. Can you be sure you know how much strength is lost from the nylon's being wet, etc.?

Yes.

5. Can you be sure that your bridle is really immune from chafe? I think a chafe-proof bridle or snubber can be imagined -- IF you have a strong eye on the bow or something which allows you to rig it without passing over or through anything. Couldn't be done on my boat, though, without major surgery. Don't know about yours.

Yes. That is a very important part of the design. I have never chafed a bridle. I'm sure that could require modifications for some boats. That means the boat designer goofed, since anchoring is very important.

A simple solution is to use a short length of something chafe-proof--Dyneema covered in chafe gear--through the chocks. Anyone can do this.

What if your bridle goes "bang", as has happened to so many of us? Would you be happy to just let your chain run out and your boat go onto the rocks?

A chain should always be belayed by some strong secondary means, even if only by lashing the bitter end to something stout. I do not believe anyone suggested otherwise. If I said cat sailors depend on the bridle, what I meant was that the boats will yaw without one. But the chain is also belayed. As you point out, this is just... obvious.

xxxxx

[Dockhead]

Originally Posted by thinwater

xxxxx

OK, that all sounds quite reasonable. Thanks for the interesting discussion.

Also, I found your actual measurements of dynamic loads as corresponding well to AYBC to be a very valuable data point.

As to chafe, I also came to the conclusion that Evans' method with a Dyneema leader would be the best for my boat, in case I needed to anchor in a hurricane (fat chance at 60N ) or otherwise had a big concern about chafe. I do not however believe that there is any 100% sure way to avoid it on my boat. I lead my snubber over my second bow roller directly aft to an inner forestay chainplate. Normally it wouldn't touch anything except the smooth bronze roller. But in a violent storm with violent yawing, all bets are off as the boat lashes around. I have chafed through or almost through an expensive Dyneema sheet, with just a couple of hours slight contact with a loose cotter pin on a shroud. Dyneema is far better, but still not immune to chafe. Maybe a wire rope strop would be better for this.

[lancelot9898]

I haven't read all the responses, but one thing that I view as a negative with 3 stand nylon is the amount of stretch. Now, it can be a positive by reducing the dynamic loads on the boat(and anchor) during wave action or wind gusts, but I can tell you that I will no longer stay aboard during a hurricane. I was anchored(with a brand new Tayana-37) about 25 years ago in a protected cove with 60 feet of 3/8 inch BBB chain spliced(with an I splice without the thimble) to 5/8 inch three strand nylon. I was on a single 35 lb Cqr anchor and probably had 100 feet of nylon out in addition to the chain. There were wind gusts throughout the night that were in the 90 knot range and when the gusts subsided the built up energy contained in that nylon would propel the boat as if we were sailing. Kinda like releasing a rubber band. The nylon was doing it's job, but it was a very unpleasant night and day.

[ranger58sb]

Originally Posted by donradcliffe

I was convinced to go all chain when we pulled up the anchor at Pitcairn after 3 nights. The rode was chafed halfway through, and wouldn't have lasted another night. This was with 60 ft of chain in 35 ft of water.

Assume you mean the rope portion of your combination rode was chafed halfway through?

What kind of rope? What did it chafe on?

-Chris

[Jim Cate]

With all the talk of super long snubbers, do you not loose the benefit of the catenary weight and length for the portion of the rode between bow and snubber attachment point? If one has, say a 100 foot snubber on say, a 200 foot chain rode, you loose the energy absorbtion of half of the catenary, which as DH points out, is considerable. I wonder where the crossover between loss of catenary and gain of elasticity of snubber occurs?

Jim

[Cheechako]

I like 3 strand because of the ability to braid it quik and easy. I like multiplait nylon because it doesn't tangle like 3 strand. I usually get 3 strand as it backs up my chain anyway. On 47 ft mono and 42 ft cat I used 5/8 three strand for the snubber. Doing it again I would probably use 3/4 for the snubber. Nylon stretches a lot even though it's that big. Don't worry about it not stretching enough... In 35-40 knots of wind I'm thinking the 5/8 snubber (double line cleated) stretched 3-4 ft or so.

[estarzinger]

Originally Posted by Dockhead

Dashew makes some what seem to me like pretty strong arguments against nylon rodes in this:

Attachment 148991

Among other things, he says that nylon is approximately 10 times more vulnerable to chafe than polyester.

I use polyester for all my non-chain rodes, personally. I find that they give plenty of stretch, at least on my boat. I always use much more scope with rope rodes, than I do with chain, which also helps with stretch.

I think the different material characteristics are pretty clear, and as I said above, I agree with him on the para-anchor application, but for ground anchors I'm all in on nylon. It's just reflective of different personal trade-offs, and I can understand the other choice.

[four winds]

I'm not a real cruiser by CF standards. Just a coastal vagabond on the Gulf of Mexico, seven years now fulltime. Usually anchor in about 7-8 ft. of water. Most ever was probably about 14'. Always mud or mud/shells, usually pretty sticky.

Boat is 32', about 14'000 lb. loaded on lift scale at haulout a couple of years ago.

First few years was a cqr, boat length of 5/16ths chain and 5/8ths 3 strand nylon. In those years was several incidents of trouble that usually reset within a boat length. The long 3 strand backing the chain stretched and worked well to absorb the ubiquitous sheering at anchor. But the worn out CQR underperformed. I knew I would upgrade when possible on my budget.

The last 2 1/2 years has been on a new style roll bar anchor and 3/8ths G3, all chain. I'm about caught up on the lost sleep from the CQR days, lol. The anchor is not oversized, but the chain is, in my opinion.

The bridle/snubber is short, 3/4 inch 3 strand nylon. The chain hook lies at the water's surface when slack. It doesn't stretch, maybe an eighth of and inch in strong wind, watching it at the chocks. Never needs chaff protection. After these years of continuous anchoring hardly shows any sign of wear.

From reading this thread I would say it's actually a belay bridle, not a snubber.

Sometimes when I know a storm will come, I'll hitch on a backup snubber after the chain hook in case something fails. And bouy the bitter end of my chain in case I have to dump and run. It seems everywhere I go, when the wind blows boats go walkabout. Just today, winds were over 20, maybe 25 knots for a bit. Two boats moved, one a little, one a lot.

Anyway, it seems my heavy chain for my boat provides all the shock absorbing I need. And I feel good about the large bridle belay. Over 800 consecutive days at anchor and counting. Many times winds over 30 knots. Once last year for over 36 hours, winds peaked around 45 for more than hour with max gusts measured at 78 knots at a weather station one mile away.

Five boats ended up on the beach, two just missed me on the way. I didn't budge. What a night.

Seems different things work for different people, boats, and anchorages. Gotta find what is best for you.

Interesting discussion.


Edit to add,.... correction. Just measured, belay bridle is 1" 3 strand nylon, not 3/4.