Stealth mode - New Generation Ropes

[Seaworthy Lass]

I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.

Gosh, does it really have to be 1000?

[Dockhead]

Originally Posted by Seaworthy Lass

I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.
I must stop flirting.

Gosh, does it really have to be 1000?

.

[s/v Jedi]

Thanks for the kind comments SeaWorthy! It seems that today I'm just tying the soft shackles as presented by those much more involved and smarter than me :-) I had not thought they would improve as much as they did.

On Brummel locks and stitching: Yes I think stitch and long bury will outperform a Brummel splice but like Dockhead writes: how does the stitching hold up over time as compared to the Brummel lock? Clearly the Brummel lock will hold up as good as the line itself, while sewing thread has proven to deteriorate much faster than that, even at V346 size.

When a splice is under load, none of the locks are needed. The drag device is jammed up in a bag most/all of it's life, where the lock for the splice is crucial. While there is no UV damage inside that bag, mold and moisture may wreak havoc and I would feel more comfortable with a Brummel lock.

Which brings me to the next point: assume that the Brummel lock reduces the strength to 85% of the line used. What happens is that the splice still survives destructive testing because another part fails earlier... like where the loop goes around a low friction ring or itself?

About the low friction rings: I love them. But is each one X-rayed to check for consistent molecular structure throughout? I would never use it as the guardian where a single point of failure of it means it's lost to the seas.

About my idea of the Brummel lock in the middle of the bridle: in my proposed setup it's 80% strength retention is not used at all, just it's locking mechanism. All the strength is provided by the Spyderline stitch and seize. As is often the case, these time proven methods are overlooked and their performance underestimated. Check https://www.practical-sailor.com/iss...g_11521-1.html

[Seaworthy Lass]

Originally Posted by s/v Jedi

On Brummel locks and stitching: Yes I think stitch and long bury will outperform a Brummel splice but like Dockhead writes: how does the stitching hold up over time as compared to the Brummel lock? Clearly the Brummel lock will hold up as good as the line itself, while sewing thread has proven to deteriorate much faster than that, even at V346 size.

When a splice is under load, none of the locks are needed. The drag device is jammed up in a bag most/all of it's life, where the lock for the splice is crucial. While there is no UV damage inside that bag, mold and moisture may wreak havoc and I would feel more comfortable with a Brummel lock.

The stitching is not done with thread. It is done with UHMWPE the same diameter as a strand of the rope. This is advised by Timms, who splice Acera for big ship use in diameters up to 80 mm. Samson suggest using nylon or polyester, but this is one instance I prefer to follow Timm’s advice, the manufacturer of the rope I am using. Both of them state the cordage used for stitching is the same diameter as a strand of the line.

Originally Posted by s/v Jedi

Which brings me to the next point: assume that the Brummel lock reduces the strength to 85% of the line used. What happens is that the splice still survives destructive testing because another part fails earlier... like where the loop goes around a low friction ring or itself?

Agreed.
There is a loss of around 10-15% if you are using a cow hitch, so there is no additional penalty with the loss of strength of the Brummel.

Originally Posted by s/v Jedi

About the low friction rings: I love them. But is each one X-rayed to check for consistent molecular structure throughout? I would never use it as the guardian where a single point of failure of it means it's lost to the seas.

Yes. Maybe that is why I am just not pouncing on this idea despite the fact it seems so good. Logically though, there could be a defect in the line, but I guess just one strand may give way. Possibly not a big concern if the system is over specified?

SWL

[Dockhead]

Originally Posted by s/v Jedi

. . . About the low friction rings: I love them. But is each one X-rayed to check for consistent molecular structure throughout? I would never use it as the guardian where a single point of failure of it means it's lost to the seas.. . .

But every element of the system might have a hidden defect. I don't know why we should single out the ring.


But the point is valid, just I think it's wrong to single out a ring as opposed to anything else we use for this crucial junction or any other part of the system.


Maybe this calls for proof testing the entire drogue? Maybe even the anchor points? I was thinking about this the other day.

[Seaworthy Lass]

Flashback to 2013.

This is the thread that Jedi started on soft shackles:

http://www.cruisersforum.com/forums/...es-102779.html

And below is the image that inspired me to give it a go.

Jedi, I love the safety factor of your long tails .
I have preached in the past not to cut off the tails of the diamond knot right at the knot, let alone burning them there.

Very interestingly, I looked at two new catalogues from Southern rope that are titled “Commercial” and “Marine” (ie yachting). Soft shackles in the latter are shown burned off at the top of the knot. In the former they have a decent tail.

SWL

[s/v Jedi]

Originally Posted by Seaworthy Lass

The stitching is not done with thread. It is done with UHMWPE the same diameter as a strand of the rope. This is advised by Timms, who splice Acera for big ship use in diameters up to 80 mm. Samson suggest using nylon or polyester, but this is one instance I prefer to follow Timm’s advice, the manufacturer of the rope I am using. Both of them state the cordage used for stitching is the same diameter as a strand of the line.

Okay, that would be fine then, I would be happy with that. I have stitched with the smallest size Spyderline which worked great as well. I believe it is 1.8mm line composed of 1mm Dyneema with polyester cover.

Yes. Maybe that is why I am just not pouncing on this idea despite the fact it seems so good. Logically though, there could be a defect in the line, but I guess just one strand may give way. Possibly not a big concern if the system is over specified?

With rope you not only have all the other strands backing up a failed strand, you can also see failed strands with the naked eye. For metal fittings, X-ray is the only way to know if it's good when life depends on it. I don't know what kind of metal is used for the low friction rings but I think it's aluminium and thus suspect to work hardening and stress cracks.

[s/v Jedi]

Originally Posted by Seaworthy Lass

Flashback to 2013.

This is the thread that Jedi started on soft shackles:

http://www.cruisersforum.com/forums/...es-102779.html

And below is the image that inspired me to give it a go.

Jedi, I love the safety factor of your long tails .
I have preached in the past not to cut off the tails of the diamond knot right at the knot, let alone burning them there.

Very interestingly, I looked at two new catalogues from Southern rope that are titled “Commercial” and “Marine” (ie yachting). Soft shackles in the latter are shown burned off at the top of the knot. In the former they have a decent tail.

SWL

Indeed, I believe the long tails as well as the seizing that locks them together prevent a failure mode completely.

That old thread is funny as I complained about the lack of a stopper knot and then a year later the button knot invention comes up

[thinwater]

A slightly off-topic, half baked idea I offer only for thought.


Sometimes you want an adjustable bridle, typically for steering drogue. What if you anchor the bridle leg to a stern cleat, through the LFR, and then to a winch? only about 60% of the winching effort and 1/2 the load on the winch.


My concern would be chafe, but for a steering drogue that is not so dangerous; at worst, you winch it in and re-rig. I would not suggest this for a JSD. Perhaps a pair of blocks is better.



I have a strong interest in steering drogues because I once bent a rudder and had to use one. It worked out. Without a means of steering you are more or less screwed, on a raft going in circles.

[Seaworthy Lass]

Originally Posted by thinwater

A slightly off-topic, half baked idea I offer only for thought.

Sometimes you want an adjustable bridle, typically for steering drogue. What if you anchor the bridle leg to a stern cleat, through the LFR, and then to a winch? only about 60% of the winching effort and 1/2 the load on the winch.

My concern would be chafe, but for a steering drogue that is not so dangerous; at worst, you winch it in and re-rig. I would not suggest this for a JSD. Perhaps a pair of blocks is better.

I have a strong interest in steering drogues because I once bent a rudder and had to use one. It worked out. Without a means of steering you are more or less screwed, on a raft going in circles.

Lots of my ideas are half baked . But brainstorming is very, very effective within a group. The pool of knowledge is deep. Even if proposals are shot down in flames, they often spark all sorts of other wonderful ideas, some of which are bound to lead to solutions.

I think the key is to put ego aside in discussions like this and not worry if you end up with egg on your face. No room for aggression or scorn in discussions like this either. If all possible ideas, half baked and otherwise are not proposed, it slows the process dramatically.

Now regarding your steering drogue issue. Would not a few LF rings arranged to give you some purchase be useful? That would decrease the load on the winch dramatically.

SWL

[Dockhead]

Originally Posted by thinwater

A slightly off-topic, half baked idea I offer only for thought.


Sometimes you want an adjustable bridle, typically for steering drogue. What if you anchor the bridle leg to a stern cleat, through the LFR, and then to a winch? only about 60% of the winching effort and 1/2 the load on the winch.


My concern would be chafe, but for a steering drogue that is not so dangerous; at worst, you winch it in and re-rig. I would not suggest this for a JSD. Perhaps a pair of blocks is better.



I have a strong interest in steering drogues because I once bent a rudder and had to use one. It worked out. Without a means of steering you are more or less screwed, on a raft going in circles.

Why half baked? I think it's a great idea. Adding purchase will reduce forces and add control. A LFR will make this a doddle. You just need decent fairleads, and if you do any bows-to mooring, then you must have them already . . .

[Seaworthy Lass]

Originally Posted by Seaworthy Lass

Now regarding your steering drogue issue. Would not a few LF rings arranged to give you some purchase be useful? That would decrease the load on the winch dramatically.

SWL

What type of rope would you be using? Drag is much higher if it is not slippery. Regarding LF rings, they are not designed for lots of movement of the line, particularly if any movement is via an acute angle over the ring. I trialled a Bullseye incorporated in a soft shackle on our yankee sheets on our last boat. It was the highest load I could think of on board. The dyneema actually melted as it went over the LF ring (the weave itself looked unchanged). So although I would not discard an LF ring in this application, be prepared to check for degradation of the line if you are using the LF rings in this application.

SWL

[thinwater]

Originally Posted by Seaworthy Lass

What type of rope would you be using? Drag is much higher if it is not slippery. Regarding LF rings, they are not designed for lots of movement of the line, particularly if any movement is via an acute angle over the ring. I trialled a Bullseye incorporated in a soft shackle on our yankee sheets on our last boat. It was the highest load I could think of on board. The dyneema actually melted as it went over the LF ring (the weave itself looked unchanged). So although I would not discard an LF ring in this application, be prepared to check for degradation of the line if you are using the LF rings in this application.

SWL

Yes, all of that. I use LFR and understand. It was just a thought I had when reading the prior LFR discussion on this thread.


What I am not fond of is an adjustable bridle that consists of a main line deflected by a block on a second line. First, the apex angle cannot be less than 60 degrees in theory, and in practice closer to 90 degrees due to friction. The reasons should be obvious and were discussed above. Second, if the boat yaws strongly to one side (odd wave) there is nothing to stop the bridle from shifting to balance the angles on each side of the block. Depending on the boat, this can pin the boat on one side (been there, done that). In strong weather, the winch may not be strong enough to pull the bridle back to center.



Tried it, not a fan, and I encourage you to try it in fair weather. IMO, if it is remotely long enough to work, it becomes unstable. You really don't want to try it for a steering drogue in strong weather. Use a gripping hitch instead.

[Breaking Waves]

Been away - long drive, not sure what I have missed but chaff seems the issue of the day. I might ask a simple question does anyone have a photo actually showing significant chafe at this cow hitched connection point? I remember when people did not want to use rope to chain splice because they thought there would be a lot of chafe at the connection link, but it turns out there is essentially zero (when properly done). So I am just wondering if we have any empirical evidence there is an actual chafe problem here?

Also, with all the various textile solutions - you can certainly put chafe sleeves on. This is dead easy on a loop splice, a little bit more tricky on a doubled over grommet (but still doable - see various discussions about Yale loups ). You could even put doubled chafe guards on.

This is just an opinion but I doubt you will find a more reliable solution than spliced loop bridles with chafe covers, prussic hitched on a tripled loop/grommet with chafe cover. The triple loop with give quite a bit of meat for the prussic hitches to crunch on - I would guess these hitches will not move much once tight except in that once a lifetime breaking wave initial load.

Originally Posted by Dockhead

Bullseye ......There's no throat tearing, so it will simply be as strong as the splices.

perhaps, perhaps not.

With SWL's loop connection idea there are no theoretical engineering concerns and there are probably no significant hidden "got-ya's" because quite similar constructions are used in commercial high load/safety applications (high load slings and loops and quite common).

The Bullseye is certainly very attractive and quite creative, and also can be made very strong by picking the line size. However SWL correctly say there is no data/calculation on how strong or reliable it actually is. There, in fact, are theoretical engineering concerns, where the strands bear on each other - that is likely a 1:1 bend (a bend with 10 degrees or more of deflection) with the associated (50%ish) significant strength reduction and there could also be some rubbing (which might create heat or chafe) between the strands if the load is not steady on the ring. Empirically I am not aware of a construction like this used in the 'serious commercial' applications - that may be because it is flawed or it may be because no-one thought of it - IDK. From a practical standpoint, in the vast majority of yachting applications, it is almost certainly just fine because the base case (using normal size cordage) will be quite strong no matter the above concerns. But the fact we don't know how strong it, we have no calculation, makes it difficult to properly size for a real super high load safety/survival type applications like the drogue.

[Breaking Waves]

Originally Posted by Seaworthy Lass

Samson recommend a throat proportion of 3:1 and preferably 5:1

I have never seen thimbles with a 5:1 ratio. I would be wary of thimbles in this application as well, even if there is no risk of chafe.

SWL

I also generally like Samson's recommendations, and 3:1 is often achievable, but the 5:1 recommendation is odd because (as you comment) it is not followed with any of Samson's own thimbles and by very few spliced loop commercial applications. I guess either it is an 'aspirational' recommendation or somehow got mangled/taken out of context in editing.

BTW, if you want to know what the throat angle will be with a specific bridle geometry, it is dead easy to just make a small scale version and measure. Use say 3 or 6mm dyneema (it does not matter) and tie the loops rather than splice (just for easy/speed). You just need to get the ratio of bridle length to distance between base of bridles (transom width) correct. you can do in 5 minutes pretty much anywhere. The geometry will scale exactly.