Stealth mode - New Generation Ropes

[Seaworthy Lass]

Originally Posted by Seaworthy Lass

Dockhead, just mock it up
I made exactly the same incorrect assumption.

SWL

Dockhead, it makes more sense once you consider that the leader is acting to pull the bridle legs together.

[Seaworthy Lass]

Originally Posted by fxykty

Option 2 with a single loop. Please explain how/where you are incorporating a loop. Thanks.

I have drawn a diagram.

In reality the eyes won’t be spread apart, they will be jammed together, so the length is not important as long as they are long enough to enable a strop bend to be made.

The photo shows how the junction will look. It will look just the same whether it is created by the eye of the leader or by a loop. For me, the advantage of a loop is that if/when I estimate it is time to replace the components seeing the toughest conditions, the entire leader does not need to be replaced, just the loop and bridle.

This is just what I personally consider will be best. I recognise other solutions may work equally well or maybe even be better, but I need to make a judgement call and this is it for now:

[Dockhead]

Originally Posted by Seaworthy Lass

Dockhead, it makes more sense once you consider that the leader is acting to pull the bridle legs together.

Well, I did a thought experiment with blocks on the ends of the bridles. So the force of the system is levering the bridle legs together via that part of the leader eye loop which is between the two bridle eye loops?


If that's true, then we've been wasting our time - with a reasonably long leader eye loop, then there's nothing at all wrong with the way my drogue is already built and no need for any of the other solutions we've been working on.

[Seaworthy Lass]

Originally Posted by Dockhead

Well, I did a thought experiment with blocks on the ends of the bridles. So the force of the system is levering the bridle legs together via that part of the leader eye loop which is between the two bridle eye loops?


If that's true, then we've been wasting our time - with a reasonably long leader eye loop, then there's nothing at all wrong with the way my drogue is already built and no need for any of the other solutions we've been working on.

LOL, yes and no. I have been repeating this.

If your leader eye is super long then one problem is almost eliminated - the tearing force at the throat. Putting a loop in the junction eliminates the this issue entirely, even using two cow hitches.

That is why I put 5) in as an option in Fxy’s list a few posts back. The current system is still an option if the leader eye is long enough.

There are other possible issues though. Two cow hitches sit a fair distance apart and when load is on one leg they may be sliding around when made up in slippery UHMWPE, something they may not have done in double braid polyester.

The second issue is the bends are fairly sharp with a proper cow hitch. These hitches are probably being yanked back and forth as load transfers between the legs. I don’t know much about bending fatigue in UHMWPE, but the thought of this does not sit comfortably with me given the constant bending back and forth is occuring at high loads for a prolonged time.

We actually know very little about how well UHMWPE will perform long term in this application.

If the movement with transfer of load can be minimised and the bends can be made gentler why not do this?

SWL

[Dockhead]

Originally Posted by Seaworthy Lass

LOL, yes and no. I have been repeating this.

If your leader eye is super long then one problem is almost eliminated - the tearing force at the throat. Putting a loop in the junction eliminates the this issue entirely, even using two cow hitches.

That is why I put 5) in as an option in Fxy’s list a few posts back. The current system is still an option if the leader eye is long enough.

There are other possible issues though. Two cow hitches sit a fair distance apart and when load is on one leg they may be sliding around when made up in slippery UHMWPE, something they may not have done in double braid polyester.

The second issue is the bends are fairly sharp with a proper cow hitch. These hitches are probably being yanked back and forth as load transfers between the legs. I don’t know much about bending fatigue in UHMWPE, but the thought of this does not sit comfortably with me given the constant bending back and forth is occuring at high loads for a prolonged time.

We actually know very little about how well UHMWPE will perform long term in this application.

If the movement with transfer of load can be minimised and the bends can be made gentler why not do this?

SWL

My red "We've Been Overthinking This!!" warning light is flashing urgently!

[Seaworthy Lass]

Originally Posted by Dockhead

My red "We've Been Overthinking This!!" warning light is flashing urgently!

Possibly correctly. It is nice to get things well engineered though.

I made the decision regarding what to do a couple of weeks ago and I am not stressing over this.

I initially assumed, as you did, that the angle of the leader’s eye was governed by the bridle leg angle, which meant a loop at the junction was essential in this set up. I think it is still a good idea, but a long leader eye may be nearly as good.

That small eye that was depicted early in the discussion rings serious alarm bells for me. I guess the main alert is that if anyone has made up a small eye for the leader and tied on two cow hitches, as in the diagram (not impossible as it looks just like the eye of a thimble), then it needs to be redone.

SWL

[s/v Jedi]

If you take option 1, all you need to prevent sliding of the slack bridle leg(s) is one short piece of small stuff. Just lay the three main parts so that the eye splices are positioned correctly, then tie them together with the small stuff like a shoe lace. A wrap or two and a square knot would do. A little poke and tap with a hot knife to make the knot permanent so it doesn't become undone and there you are. The only force ever on it is that of a slack bridle flopping around.

That said, I would go for #2. The only reason I would prefer it is because it's easier to take apart. I have cow hitched Dyneema loops for a while and never had trouble and always could take them apart again... after some massaging even with bare hands

[Dockhead]

Originally Posted by s/v Jedi

If you take option 1, all you need to prevent sliding of the slack bridle leg(s) is one short piece of small stuff. Just lay the three main parts so that the eye splices are positioned correctly, then tie them together with the small stuff like a shoe lace. A wrap or two and a square knot would do. A little poke and tap with a hot knife to make the knot permanent so it doesn't become undone and there you are. The only force ever on it is that of a slack bridle flopping around.

That said, I would go for #2. The only reason I would prefer it is because it's easier to take apart. I have cow hitched Dyneema loops for a while and never had trouble and always could take them apart again... after some massaging even with bare hands

That seems all correct to me.



Concerning cow hitches and Dyneema -- I am still using the original strops for my sheet lead system, 5 years and God knows how many miles later! Cow hitched to strong padeyes through-bolted through the rail, roughly 1:1 size relationship between diameter of the cordage and diameter of the padeye bail. Tons of force, years under the sun, and no sign of wear or weakening or any kind of deterioration. I think we need to listen to what SWL says about damage from compression loading and unknown failure modes of UHMWPE, but my experience so far is that the stuff is bloody durable! That UHMWPE which is well coated just goes on and on.

[s/v Jedi]

I have 15 year old Amsteel Blue runners that I'm still not replacing. They are cow-hitched around a 3/8" diameter steel link above and have an eye splice to a shackle with block that is 5/16" diameter below. I don't see a single torn fiber, not even on the outside that is severely discolored by UV exposure.

I would replace it for parts where life could be at stake like lifelines. I think a 10 year schedule for that (in the tropics) is safe.

[Breaking Waves]

Was just looking at one of these, and thought of this thread.



If someone wanted a metal solution for connecting the bridles to rode.

The one I was looking at was proof tested to 300,000lbs and weighed 75lbs.

But a machine shop could pretty easily cut a (much) smaller one, more suitable for yachting use, from aluminum plate (or SS). There is no weld strength issue. The inside corners are rounded so you can either splice directly to it or use shackles.

I personally prefer the all textile approach for our drogues . . . but this would be a design if you wanted metal.

[thinwater]

Originally Posted by olaf hart

I suspect an old tyre on a bridle would be effective as emergency steering, it’s a matter of using whatever you have at hand.
We already have a Jordan drogue and an old Seabrake on board, although it does need a new wire ring...

Actually, in calm to moderate weather, an anchor suspended under a large fender works reasonably well. People have sailed long distances on such jury rigs. (Article of mine in last Good Old Boat.) In storm conditions, a commercial drogue would be easier to rig and more stable.

[fxykty]

Hey SWL, I see that you’ve put a whipping on the throat of your shackles. What material and size do you use for that whipping? Is it Dyneema to preserve the slipperiness of the original legs?

Here is a photo of mine, made out of 8mm coated Dyneema. It will be used to attach our anchoring bridle to our chain. The 8mm loop just fits through our 12mm chain. It’s about 30cm long, which means long enough to have 24cm tapered buries and not interfering with the chain.



Thanks for your instructions!

[Seaworthy Lass]

Originally Posted by fxykty

Hey SWL, I see that you’ve put a whipping on the throat of your shackles. What material and size do you use for that whipping? Is it Dyneema to preserve the slipperiness of the original legs?

Here is a photo of mine, made out of 8mm coated Dyneema. It will be used to attach our anchoring bridle to our chain. The 8mm loop just fits through our 12mm chain. It’s about 30cm long, which means long enough to have 24cm tapered buries and not interfering with the chain.

Attachment 192652

Thanks for your instructions!

Hi Fxy
I have experimented a bit by adding the whipping at the base of a few shackles. The purpose is to create the greatest diameter for the noose to go around. I have noted that under load the two seperate legs move around so that the noose (the weak point in this design) is passing around the narrowest possible arrangement. The whipping hold the two legs together snuggly and ensures a maximum uniform diameter.

I have simply used waxed 1.5mm polyester whipping twine (Gottifredi Maffioli or Liros).

I have no load testing equipment to test out this theory and I doubt the soft shackles I make are ever taken close to MBS, so it is probably immaterial, but it is fun to play with design .

SWL

[fxykty]

I’m about to receive the Acera Amundsen rope that I ordered from Greenline Fishing Gear for our JSD and I’m starting to think about the actual eye splicing and cone connections.

First off, my Selma fid kit maxes out at 10mm - I’m not sure that I’ll be able to squeeze the 12mm Acera onto it. Will I need a larger fid, or could I just taper the tail to make it fit the 10mm? The 7.5mm fid was too small working with 8mm UHMWPE for the soft shackles I’ve been making.

Second, is there any benefit to making a Brummel lock eye splice with long bury as opposed to a plain long bury eye splice? I like the idea of the eye being locked when the JSD is not fully loaded or cycling between partial and full loads, or in the case of the bridle legs flopping around unloaded. Does the use of the Brummel lock mean that the splice bury does not need to be lock stitched? Are there any negatives to making a Brummel eye splice? Of course, making a Brummel lock with only one free end means inverting the Brummel holes - I’m not sure if that’s possible with larger diameters. Also not sure that a spliced eye will fit through a hole. So it may not even be possible, sigh.

Finally, the joy of attaching six tapes per cone to the rode for 156 cones. I understand the recommendation for Acera is to send the tape through from one side, then back through to the original side, then knotted (figure 8?) to keep it from sliding through. Correct?

[Seaworthy Lass]

Originally Posted by fxykty

I’m about to receive the Acera Amundsen rope that I ordered from Greenline Fishing Gear for our JSD and I’m starting to think about the actual eye splicing and cone connections.

First off, my Selma fid kit maxes out at 10mm - I’m not sure that I’ll be able to squeeze the 12mm Acera onto it. Will I need a larger fid, or could I just taper the tail to make it fit the 10mm? The 7.5mm fid was too small working with 8mm UHMWPE for the soft shackles I’ve been making.

I use wire type fids almost exclusively. I purchased a set of three “needle” style fids from the Dusseldorf boat show a few years ago and have never looked back. The principle can be easily reproduced simply by bending some SS wire in half and twirling the raw ends around a bit of timber to act as a handle. I have done this with some very thin wire to work with 3 mm single braid.

Retrospectively, I wouldn’t bother buying any fids knowing how well this simple system works.

When burying the tails of soft shackles I can get much closer to the base of the stopper with a wire fid than a Selma one. They also work much better for splicing double braid polyester. The only thing I use my Selma fids for now is when I am passing one bit of braid perpendicularly through another (eg when creating an eye).

This is what a “needle” fid looks like. I now taper the tail before threading it through the eye, as it then buries very smoothly: