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post #11 of 47 Old 10-30-2017
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Re: What if No-Chain?

Chainless anchor rodes are possible. Such would depend on: 1. the 'penetration power' of the anchor, and 2. the fluke angle of the anchor. Inotherwords, the 'trigonometry' (especially during the 'setting phase') has to probably be equal to a partly chained rode.

The obvious functional 'advantage' of part chain or all chain rode is during the 'setting' (and re-setting under changing wind direction and changing current direction) of the anchor; the chain holds the anchor stock essentially level with the bottom and thus enables an approximate 15 'extra' angle (with 7:1 scope) during the 'penetration into the bottom phase' of anchoring.
In all probability one would have to initially 'set' such a chainless anchor with a ~10:1, or more, initial scope then haul in to ~7:1 ... all to get that initial setting angle of the flukes 'into' the bottom as is done with a part chain rode.

The Fortress double angle (choice of 32 fluke angle for 'sand' and 45 fluke angle for soft mud) would probably be my choice for a chainless rode ... just set it at the 45 angle and forget it; but, use an initial scope of 10:1 for sand and 7:1 for soft mud.
(However, Ive found that double angled Fortress anchors sometimes don't always easily 'reset' during ~180 current and wind shifts, as does the heavily-weighted tip 'plow-type' anchors)

Trigonometric (implied free body force diagram) analysis as attachment. The implication is that added chain gives weight/catenary and thus holds the anchor flukes in a much deeper penetration angle, especially during the 'setting' process. The analysis seems to imply a LOSS of ~10 scope angle due to NO catenary during the initial setting/digging-in phase; hence, the probable need to set such with a much longer scope during the 'setting' phase.
Correction to attachment: (TAN ^-1) 1/7 = .17 = 8
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post #12 of 47 Old 10-30-2017 Thread Starter
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Re: What if No-Chain?

Quote:
Originally Posted by Noelex View Post
There are some cheap Dyneema materials (or more correctly HMWPE as Dyneema is a trade name) appearing on the market because the Dyneema patents are expiring. Acera is one such rope.

These show a lot of promise. The main advantage is better chafe protection than traditional fibre rodes. There are problems that need to be overcome. It floats and the lack of elasticity means a snubber is needed. Attaching the snubber is not easy....
I've been doing some side-to-side chafe testing on abrasive materials, and believe it or not, Dyneema single braids don't do much better than nylon and perhaps not as well as polyester. In a sense, the Dyneema chafe thing seems to be an exaggeration. End to end it runs smoothly, low friction, and thus does not chafe, but side to side across a rock is completely different. This is part the result of a loose construction; tight weaves like WR-2 are much more resistant.

Thus Dyneema may be a part of the answer, but it will need a chafe cover.

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Re: What if No-Chain?

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Originally Posted by RichH View Post
... The Fortress double angle (choice of 32 fluke angle for 'sand' and 45 fluke angle for soft mud) would probably be my choice for a chainless rode ... just set it at the 45 angle and forget it; but, use an initial scope of 10:1 for sand and 7:1 for soft mud....
I suggest you try the Fortress at the 45 degree setting in some firmer bottoms. I think you will find it may not set at all. That has been my experiences, and it is that advice of Fortress that the 32 degree setting is the default unless you specifically know the bottom is very soft mud. But I like the thought process.

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Re: What if No-Chain?

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Originally Posted by pdqaltair View Post
I've been doing some side-to-side chafe testing on abrasive materials, and believe it or not, Dyneema single braids don't do much better than nylon and perhaps not as well as polyester.
Thanks. This type of testing is very valuable, so I look forward to the results.

I am surprised. Cutting the material with a knife especially a slightly dull knife which is not unlike the effect of anchor rope that is caught under a rock suggests the material is much tougher than polyester, but these are just impressions not controlled experiments. Perhaps the perception is wrong.

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Re: What if No-Chain?

I have often thought of using a flat rope nylon webbing rode, for space and weight saving. The cost is significantly more than the nylon double braid I use now with a fortress anchor for my 20ft 3,500lb boat on the mud and sand bottom of the Delaware and Chesapeake.

I have never had a dragging problem and rarely anchor in more than 20 ft depth in the Delaware River and Bay with its large tidal current range.
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Re: What if No-Chain?

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Originally Posted by Ulladh View Post
I have often thought of using a flat rope nylon webbing rode, for space and weight saving. The cost is significantly more than the nylon double braid I use now with a fortress anchor for my 20ft 3,500lb boat on the mud and sand bottom of the Delaware and Chesapeake.

I have never had a dragging problem and rarely anchor in more than 20 ft depth in the Delaware River and Bay with its large tidal current range.
Unless you cover the webbing, from your hawse hole to the connection to the anchor, you can expect very short service life and significant loss of strength due to the long term UV exposure.
When using nylon 'rope', either 3-strand or double braid, the very same section will be noted have quite severe UV (burn) degradation ... but only on the external diameter.
Polyester probably should be the choice because it withstands UV exposure and with less degradation, much better than Nylon(6); polyester tubular webbing is very 'rare'.

The same UV effect is easily noted in jacklines (used with teathers) when long term / long distance sailing when left on deck for a couple of months exposure.
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Re: What if No-Chain?

Quote:
Originally Posted by RichH View Post
Chainless anchor rodes are possible. Such would depend on: 1. the 'penetration power' of the anchor, and 2. the fluke angle of the anchor. Inotherwords, the 'trigonometry' (especially during the 'setting phase') has to probably be equal to a partly chained rode.

The obvious functional 'advantage' of part chain or all chain rode is during the 'setting' (and re-setting under changing wind direction and changing current direction) of the anchor; the chain holds the anchor stock essentially level with the bottom and thus enables an approximate 15 'extra' angle (with 7:1 scope) during the 'penetration into the bottom phase' of anchoring.
In all probability one would have to initially 'set' such a chainless anchor with a ~10:1, or more, initial scope then haul in to ~7:1 ... all to get that initial setting angle of the flukes 'into' the bottom as is done with a part chain rode.

The Fortress double angle (choice of 32 fluke angle for 'sand' and 45 fluke angle for soft mud) would probably be my choice for a chainless rode ... just set it at the 45 angle and forget it; but, use an initial scope of 10:1 for sand and 7:1 for soft mud.
(However, Ive found that double angled Fortress anchors sometimes don't always easily 'reset' during ~180 current and wind shifts, as does the heavily-weighted tip 'plow-type' anchors)

Trigonometric (implied free body force diagram) analysis as attachment. The implication is that added chain gives weight/catenary and thus holds the anchor flukes in a much deeper penetration angle, especially during the 'setting' process. The analysis seems to imply a LOSS of ~10 scope angle due to NO catenary during the initial setting/digging-in phase; hence, the probable need to set such with a much longer scope during the 'setting' phase.
Correction to attachment: (TAN ^-1) 1/7 = .17 = 8
Quote:
Originally Posted by RichH View Post
Unless you cover the webbing, from your hawse hole to the connection to the anchor, you can expect very short service life and significant loss of strength due to the long term UV exposure.
When using nylon 'rope', either 3-strand or double braid, the very same section will be noted have quite severe UV (burn) degradation ... but only on the external diameter.
Polyester probably should be the choice because it withstands UV exposure and with less degradation, much better than Nylon(6); polyester tubular webbing is very 'rare'.

The same UV effect is easily noted in jacklines (used with teathers) when long term / long distance sailing when left on deck for a couple of months exposure.
All true.

The other problem with webbing is cleating (tends to jam) and handling (hard to grab, and smaller boats this is a manual operation.

At one point I tried using 1/4-inch Amsteel as a leader. I was doing some testing regarding depth of set and holding vs. rode diameter (a smaller rode lets the anchor go deeper). There were a number of problems with this, but the most immediate was braking the anchor out. The stuff is horrible to handle under load, very difficult to cleat successfully, and you had to be VERY careful with you fingers around a load line.

The point is that for a small boat the line has to be comfortable and secure in the hands. Saving weight is great, but the 100 feet of line only weighs 5-10 pounds; saving a few more pounds at the expense of safety (both cutting and fingers) proved to be a poor trade off in my case.

Yes, I could have used steel cable, which could be used safely on a reel, but this was testing and I didn't have a big reel winch handy. In truth, the short Amsteel leader was OK except for breakout. Also, as I mentioned earlier, bare Amsteel was NOT impressive from a chafe standpoint. As an anchoring leader, it is not much better than nylon in this regard. Strange, but true. It's the loose weave. Weave seems to have more effect of chafe than the fiber type.

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Re: What if No-Chain?

Quote:
Originally Posted by Noelex View Post
Thanks. This type of testing is very valuable, so I look forward to the results.

I am surprised. Cutting the material with a knife especially a slightly dull knife which is not unlike the effect of anchor rope that is caught under a rock suggests the material is much tougher than polyester, but these are just impressions not controlled experiments. Perhaps the perception is wrong.
That was my thought as well. The stuff is so hard to cut, I find it hard to believe that it's not more chafe resistant than nylon.

But again, this is just my impression.

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Re: What if No-Chain?

Quote:
Originally Posted by RichH View Post
The obvious functional 'advantage' of part chain or all chain rode is during the 'setting' (and re-setting under changing wind direction and changing current direction) of the anchor; the chain holds the anchor stock essentially level with the bottom and thus enables an approximate 15 'extra' angle (with 7:1 scope) during the 'penetration into the bottom phase' of anchoring.
Chain does help with the initial setting process. As you point out, the catanery is beneficial. This is particularly important in difficult substrates where the anchor may be struggling to achieve the initial bite.

However, in the later part of the setting process the catanary is almost lost, as the force essentially straightens out the chain.


Quote:
Originally Posted by RichH View Post
In all probability one would have to initially 'set' such a chainless anchor with a ~10:1, or more, initial scope then haul in to ~7:1 ... all to get that initial setting angle of the flukes 'into' the bottom as is done with a part chain rode.
With a good modern anchor and a reasonable substrate, there is no need to go with very large scopes to start the initial set, even with zero catenary, but with poor substrates it is a tactic worth considering.

Quote:
Originally Posted by RichH View Post
The Fortress double angle (choice of 32 fluke angle for 'sand' and 45 fluke angle for soft mud) would probably be my choice for a chainless rode ... just set it at the 45 angle and forget it; but, use an initial scope of 10:1 for sand and 7:1 for soft mud.
(However, Ive found that double angled Fortress anchors sometimes don't always easily 'reset' during ~180 current and wind shifts, as does the heavily-weighted tip 'plow-type' anchors)
If the fluke angle is too shallow for the substrate (so using 32 when the substrate is soft enough for 45) the anchor will still work fine, but the holding power will be less than at the 45 setting. On the other hand, using a fluke angle that too steep (so using 45 when the substrate is too firm for 45) the anchor will never set, or if it sets it will rapidly break out and the holding will be very poor. You therefore need to be very careful using these wider fluke angles. You need to be sure that the substrate is soft (and it needs to very soft to use 45) where you will be dropping the anchor.

Formally noelex77, but I cannot access that account.
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Re: What if No-Chain?

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Originally Posted by Minnesail View Post
That was my thought as well. The stuff is so hard to cut, I find it hard to believe that it's not more chafe resistant than nylon.

But again, this is just my impression.
Quote:
Originally Posted by Minnesail View Post
That was my thought as well. The stuff is so hard to cut, I find it hard to believe that it's not more chafe resistant than nylon.

But again, this is just my impression.

Yeah, this was a surprise to me as well. It's tough to cut with knife or scissors. But this has been born out in multiple tests with several related methods. Additionally, Dyneema with a tight (NER's Spectra chafe Sleeve and WR-2) cross weave is quite chafe resistant side-to-side and on rocks and stanchions. It was actually testing regarding stanchion wear with synthetic lifelines that started me down this path. It seems that Amsteel is the wrong material in that application as well.

1. If the abrasive material is stone, it it so much harder than Dyneema it does not matter.

2. If the weave is loose and the material is abrasive (not smooth like a knife, it can pluck fibers out.

3. One of the primary chafe resistance mechanism is retention of cut fibers, that hence become protective, like the tip of a broom. This is the primary function of many anti-chafe coatings, like Yale Maxijacket; they retain the damaged fibers. On a loose weave, this does not happen. On a tightly woven cover, many of the fibers run cross-wise.

I invite others to test this. A simple way is to use a long pendulum with a heavy weight. I believe this better simulates what happens at anchor, with the boat yawing, than industry standard lengthwise chafe tests. The industry tests are great for measuring wear over sheaves and around guides, which is really more representative of how ropes should be used.

I'm not that big a believe in the invincibility of Amsteel. I've seen a lot of seriously fuzzed soft shackles, and one of the shroud tensioners on my boat snapped a month ago because it was rubbing very lightly, side-to-side, on a block. As I said, end-to-end is great.

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