Drogues, what do you think?

[GHA]

Not sure you read the articles carefully then. Refers to Susie Goodall trying a drogue, and then changing to less drag of ropes and going faster which she said was better. And can’t get much more extreme than the pasting in the Southern Ocean that battered that fleet.
And worth reading the full Yachting World article if you can find it. The people slowing seemed to get at least as badly pasted as those who kept moving, not least as keeping moving gets passed by much less waves and less impact. I think the winner, who fared better than most, may have been one who practised the keep moving approach. Worth reading the full article

Found some YM stuff, all here > Golden Globe Race - Yachting Monthly
" The people slowing seemed to get at least as badly pasted as those who kept moving", maybe not >
What can be learned from the 2018-19 Golden Globe Race?
"The biggest reason for yachts to withdraw was due to being rolled, by up to 360°, violently pitchpoled in waves, or severely knocked down during Southern Ocean storms."
Pretty much what the JSD is designed to prevent. Afaik no boats have been lost trailing a jsd, seems reasonable to think that many or maybe all the GG losses could have been avoided. Not much data to go on so a fair bit of assumptions to go on but still.....
Not that anything is a magic bullet, you're gonna get hammered so a few 1/4" ply washboards aren't going to cut it..,

 

[GHA]

This came up in feedly >

Best practices in deployment of the Jordan Series Drogue
https://forum.oceancruisingclub.org/Attachment380.aspx

Often wondered why people didn't deploy them 'back to front', apparently it works well keeping the tail onboard til last so says Susanne Huber-Curphey.

 

[Kukri]

I won’t call Steve Brown “a relative novice”! But yes, it’s an excellent review, and yes, there are four - four! - CCA Blue Water Medallists taking part.

As I’ve said before I find the OCC stuff consistently excellent but I also like AAC - well worth the modest sub. - because the OCC information is “from the horse’s mouth” and is in “ raw” form whilst with AAC John and Phyllis add their own commentary which is consistent and clear and once you “come to know them” you can use what they say as a yardstick to evaluate ideas and equipment.

 

[zoidberg]

Don Jordan used 3-strand nylon rope, as that was what was available to him 40 years ago. It was bulky and heavy - especially when it had absorbed its own weight in seawater - in the diameters he recommended to sustain the Peak Load, and difficult to recover. He chose to 'step down' his ropes' diameters in stages along the length of the rode to save weight and gain some economy. That introduced several splices and, by at least one manufacturer, superfluous double-figure- of-eight knots. That certainly weakened such rodes to a significant extent ( see Marlow Ropes diagram above ). It is practicaly impossible to gauge the strength of each spliced loop without testing to destruction, but it is logical that some are better than others.

Today's available ropes are much stronger than nylon, and far lighter. There seems no justification now to split the length of the rode into sections, introducing weaknesses. Opinion is split between selecting a polyester doublebraid continuous rode, or a much lighter and far stronger UHMWPE singlebraid continuous rode. See Suzanne Cuber-Humphrey's yellow Acera in pic above. Southern Ropes 'Stealth Super 12' is also very highly rated.

There has been some reports of considerable difficulty in recovery of such 'slippery rope'. Others have managed well enough. A technique has been developed - and reported in AAC/Morgans Cloud - which facilitates the securing of 'nipper-strops' for easier winching-in.

Experienced people are sharing and addressing perceived problems, resulting in answers and improvements. That surely was aero-engineer Don Jordan's intention.

 

[thinwater]

Don Jordan used 3-strand nylon rope, as that was what was available to him 40 years ago. It was bulky and heavy - especially when it had absorbed its own weight in seawater - in the diameters he recommended to sustain the Peak Load, and difficult to recover. He chose to 'step down' his ropes' diameters in stages along the length of the rode to save weight and gain some economy. That introduced several splices and, by at least one manufacturer, superfluous double-figure- of-eight knots. That certainly weakened such rodes to a significant extent ( see Marlow Ropes diagram above ). It is practicaly impossible to gauge the strength of each spliced loop without testing to destruction, but it is logical that some are better than others.

Today's available ropes are much stronger than nylon, and far lighter. There seems no justification now to split the length of the rode into sections, introducing weaknesses. Opinion is split between selecting a polyester doublebraid continuous rode, or a much lighter and far stronger UHMWPE singlebraid continuous rode. See Suzanne Cuber-Humphrey's yellow Acera in pic above. Southern Ropes 'Stealth Super 12' is also very highly rated.

There has been some reports of considerable difficulty in recovery of such 'slippery rope'. Others have managed well enough. A technique has been developed - and reported in AAC/Morgans Cloud - which facilitates the securing of 'nipper-strops' for easier winching-in.

Experienced people are sharing and addressing perceived problems, resulting in answers and improvements. That surely was aero-engineer Don Jordan's intention.

One reason to split it into sections is to have one shorter portion that could be used for emergency steering or just slowing. In fact, loosing steering is probably at least as likely as a survival storm and many boats are abandoned due to steering failure. But if it is the tail section of the JSD there is much less load there. So yeah, as much in on piece as possible makes sense. But I think it was the bridle splice (knot) that failed, not one farther down the string. Or am I wrong?

 

[zoidberg]

But I think it was the bridle splice (knot) that failed, not one farther down the string. Or am I wrong?

I queried the lady at a symposium in Southampton, with her sponsors Marlow Ropes. She was quite uncertain of exactly what had failed and where. Do bear in mind she was below when the 'once-in-a-lifetime' Monster Breaking Wave Strike happened, and the JSD had been working well for her for some time - 'hours', she said - before then. She had been tumbled about quite badly, her mast was gone, the boat was still being thrown about, the storm hadn't abated, and it was still pitchblack. She was in shock.

The best understanding she could give us was as mentioned above, and that arrangement had a spliced loop on the front-end of the leader, and a pair of bridle-legs, both with spliced loops ( probably in slightly lighter rope according to Don Jordan's notes ) and, perhaps crucially, each of those overlong spliced loops had a double-figure-of-eight bend in 'em.

So the question is what can we glean from this, and take forward.

Firstly, it seems to me that the 'triple-point' connection can/should be made stronger.
I have a closed tube thimble there, with a 'web-reinforcement' to ensure best 'D:d ' bend radius for the rode-loop and therefore strength. The open-end stainless ones become squeezed out of shape at large loads, and their points damage the rope.

Second, we can use rope today that is far stronger and lighter than DJ had available when he compiled his recommendation-tables. We should use that option.

I have made bridle-arms from rope the same strength as the main rode, I have loop-splices exactly to the rope-makers' best practice, and no superfluous knots. I've chosen UHMWPE singlebraid Dyneema-type rope, which has an MBS of rather more than twice the maximum laden displacement of my boat, and far less bulk to store. One can get Dyneema-cored, polypropylene-sheathed doublebraid to do the job well, too, but that is somewhat heavier and bulkier.

Third, the Jordan Series Drogue is there to do ONE job only - to protect against a Monster Breaking Wave Strike.

It's not there to slow the boat down a bit, nor to double as a kedge line, or..... you wouldn't use a sports parachute to polish the wings of your glider, nor would you leave your parachute at home because it's a bit difficult to repack after use.

Don Jordan was motivated by the 19 deaths in the '79 Fastnet Race, which happened in the Celtic Sea, in August. He didn't set out to provide an answer to a problem deep in the Southern Ocean, in winter. Monster Breaking Wave Strikes can and do happen in most of the seas around us - not often, but in the words of Miles Smeeton, 'Once Is Enough'.

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[thinwater]

...

Third, the Jordan Series Drogue is there to do ONE job only - to protect against a Monster Breaking Wave Strike.
It's not there to slow the boat down a bit, nor to double as a kedge line, or..... you wouldn't use a sports parachute to polish the wings of your glider, nor would you leave your parachute at home because it's a bit difficult to repack after use....

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All true, re. breakage.

I also agree with the comment that the JSD is a single-job device. In fact, it is quite poor at the other functions (slowing, emergency steering), compared to good conventional drogues (Shark, Seabrake, Gale Rider etc.) in terms of utility, durability, and function (I have tested in those functions side-by-side). A JSD is simple NOT designed to operate at higher speeds and provides less stable drag and the cones don't hold up well. But what I mention is the perception and is why sailors may like to break it into sections. Reasons include storage space, cost, and that they don't know that a JSD is poor for other functions because it was not designed for them.

I agree.

---

Why is it poor? It seems like a short section should be good for other things, and I tested with that hope. It did not work as well as purpose built designs, but it could work good enough, I supose.

• Cone that are durable deep underwater at 1-2 knots get beat up running in and out of the surface at 4-6 knots. That is why the cone damage is always in the first section.
• The load on each cone is ~ 4-10 times higher when steering than in a survival storm. Seems weird, but stress is related to boat speed, not the violence of the storm.
• They are less efficient at speed because they are too close together (they run in each other's turbulence). This is less of a problem at low speed.
• A JSD runs deep. A steering or slowing drogue runs practically on the surface. Big difference in design environment.

Finally, optimum rigging for a steering or slowing drogue is very different than for a JSD. Long subject.

 

[Kukri]

I very much agree with the observation in AAC that few of us worry as much as we should about our rudders.

Very few GRP rudders are as good as they were when new. Most leak, and have corroded internally

 

[Fascadale]

In light of what I have recently read I think I may need to now update and improve my 9 year old, and thankfully unused, JSD

My JSD incorporates traditional stainless steel thimbles with long slices in braid on braid. There seems now to be some criticism of these thimbles. What is their recommended replacement?

I also built the JSD with two separate bridle legs, each with a thimble at either end. The leader, also with a thimble at the “boat end” then shackles onto the two bridle legs

I designed it this way so that the bridle legs could stay permanently rigged when at sea whilst the main part of the system remained in a locker until required. (small cockpit)

With the new knowledge and experience we now have of JSDs is my bridle/leader system up to the job? Can it be improved? And how? ( Other than updating the thimbles)

There also now seems to be uncertainty about the weight of chain to put at the far end.

34 ft boat, about 14000 lbs, 100 (iirc) droguelets, originally built for a 26ft boat

Thanks

 

[zoidberg]

I may need to now update and improve my..... JSD.... (which) incorporates traditional stainless steel thimbles with long sPlices in braid on braid.

I also built the JSD with two separate bridle legs, each with a thimble at either end. The leader, also with a thimble at the “boat end” then shackles onto the two bridle legs. I designed it this way so that the bridle legs could stay permanently rigged when at sea whilst the main part of the system remained in a locker until required. (small cockpit)

With the new knowledge and experience we now have of JSDs is my bridle/leader system up to the job? Can it be improved? And how? ( Other than updating the thimbles) .... uncertainty about the weight of chain to put at the far end.

34 ft boat, about 14000 lbs, 100 (iirc) droguelets, originally built for a 26ft boat

I certainly won't seek to prescribe the answers you seek, or infer I 'know'.... It's early am, so here are a few 'first reactions' to your request.

Don Jordan himself warns against the use of the 'open' type of thimble, for under heavy load they distort, their trailing edges/points can press hard against the highly loaded rope. Slicing part-way through is a strong possibility.

He advocates a 'closed' style of thimble, which is reinforced across the narrow neck. There are multiple types available,. Two examples are shown below. It is important for optimum strength that the thimble maintains an appropriate 'D:d' bend ratio in the rope as specified by the manufacturer, and does not present any sharp edges. The original arrangement of interwoven cinch hitches does not develop the maximum strength in the connection.

These are not the only types that may prove suitable; they are simply some examples for which I have imagery.

Your boat is, you say, 'about 14,000lbs'. It seems important to ensure you use a realistic Laden Displacement - and not a builder's Light Ship figure - in determining what minimum strength rode you need, and how many cones.

Don Jordan's recommendations are shown in the following diagram...

It therefore seems clear that a 14,000lb boat requires rather more than 100 cones. 'OceanBrake' of Dorset suggests 107 cones . Should your Laden Displacement turn out to be closer to 20,000lbs, then 116 cones is recommended. 'OceanBrake' should be able to sell you extra cones, should those you have remain in good condition. There would be little difficulty in attaching a 'tail' carrying those extra cones onto your existing rode, if still up to the task.

Your plan to have the bridles pre-rigged and attach the leader and the rest of the kit when wanted, is reasonable. I would ask you to satisfy yourself that the shackles you choose for this are well up to the job. Many will not be.
I'd also encourage you to consider the use of 'Improved Soft Shackles' for this. They can be made up easily, and long enough, to pass a couple of times around, joining the leader to the bridle-arms thimbles. With some anti-chafe tube slipped on, such should be far, far stronger than the spliced loops - and 'bulletproof'.

Opinion differs on how best to deploy the things - whether to put the tail-weight in first, swiftly followed by the rest.... or, as Suzanne Cuber-Hurphey prefers, slip the leader out, then the section carrying the 'nearest' drogues, with the tail-weight last.

Many users have a Deployment Bag, into which the JSD is loaded in sequential loops. This seems to be best loaded when laid-out flat on a pontoon, and not in a cockpit. Others now prefer a tubular bag - like a sail bag or a large drybag - into which the JSD is loosely stuffed, with the appropriate ends kept to hand.

As to the 'right' tail-weight, opinion seems to have concluded that the weights suggested by Don J. are too light for the conditions in which a JSD will earn its keep, although there is no handy table published. I'll stick my neck out and suggest that 35-40lbs of chain in loops will be somewhere close to optimum..... but there will be other ideas.

There needs to be a Good Plan for recovering the thing, but that's for another day.

For what it's worth....

 

[Fascadale]

I certainly won't seek to prescribe the answers you seek, or infer I 'know'.... It's early am, so here are a few 'first reactions' to your request.

Don Jordan himself warns against the use of the 'open' type of thimble, for under heavy load they distort, their trailing edges/points can press hard against the highly loaded rope. Slicing part-way through is a strong possibility.

He advocates a 'closed' style of thimble, which is reinforced across the narrow neck. There are multiple types available,. Two examples are shown below. It is important for optimum strength that the thimble maintains an appropriate 'D:d' bend ratio in the rope as specified by the manufacturer, and does not present any sharp edges. The original arrangement of interwoven cinch hitches does not develop the maximum strength in the connection.

These are not the only types that may prove suitable; they are simply some examples for which I have imagery.

Your boat is, you say, 'about 14,000lbs'. It seems important to ensure you use a realistic Laden Displacement - and not a builder's Light Ship figure - in determining what minimum strength rode you need, and how many cones.

Don Jordan's recommendations are shown in the following diagram...

It therefore seems clear that a 14,000lb boat requires rather more than 100 cones. 'OceanBrake' of Dorset suggests 107 cones . Should your Laden Displacement turn out to be closer to 20,000lbs, then 116 cones is recommended. 'OceanBrake' should be able to sell you extra cones, should those you have remain in good condition. There would be little difficulty in attaching a 'tail' carrying those extra cones onto your existing rode, if still up to the task.

Your plan to have the bridles pre-rigged and attach the leader and the rest of the kit when wanted, is reasonable. I would ask you to satisfy yourself that the shackles you choose for this are well up to the job. Many will not be.
I'd also encourage you to consider the use of 'Improved Soft Shackles' for this. They can be made up easily, and long enough, to pass a couple of times around, joining the leader to the bridle-arms thimbles. With some anti-chafe tube slipped on, such should be far, far stronger than the spliced loops - and 'bulletproof'.

Opinion differs on how best to deploy the things - whether to put the tail-weight in first, swiftly followed by the rest.... or, as Suzanne Cuber-Hurphey prefers, slip the leader out, then the section carrying the 'nearest' drogues, with the tail-weight last.

Many users have a Deployment Bag, into which the JSD is loaded in sequential loops. This seems to be best loaded when laid-out flat on a pontoon, and not in a cockpit. Others now prefer a tubular bag - like a sail bag or a large drybag - into which the JSD is loosely stuffed, with the appropriate ends kept to hand.

As to the 'right' tail-weight, opinion seems to have concluded that the weights suggested by Don J. are too light for the conditions in which a JSD will earn its keep, although there is no handy table published. I'll stick my neck out and suggest that 35-40lbs of chain in loops will be somewhere close to optimum..... but there will be other ideas.

There needs to be a Good Plan for recovering the thing, but that's for another day.

For what it's worth....

Thanks for such a comprehensive reply?

The listed displacement for my boat is 11,800 lbs so hopefully 14,000 lbs “heavy” is about right, but yes a few more cones would be an easy addition

I like the closed thimbles. None of the ones I have found on Google say whether they are 306 or 316, A2 or A4. But perhaps not critical in kit that is not permanently rigged.

Deploying the drogue is going to be an adventure. In an earlier life I worked on fishing boats: “shooting the gear” was one of the most hazardous activities. My JSD is flaked into a wide mouthed duffle bag. Fingers crossed.

Glad to hear the shackled three way joint is still up to standard. I’ll have a think about the soft shackles

As you say retrieving the JSD is another matter. Time and a bit of effort, prussiks and winches.

I am also thinking about strategies to protect my Aries from the bridle legs. At the moment I’m thinking of some sort of extendable fibreglass/carbon fibre rods.

But after all the thought and effort I hope never to use the JSD????

 

[penfold]

Caught out in 8 gusting 10 on a delivery we were bare poles; tied all our mooring warps together(about 200m in all, 20mm braid) and streamed them in a big bight with a waterfilled jerrycan on the end, worked quite well on a 40' light-ish displacement boat. Drogues are a waste of money unless you are an adrenalin junky and plan on being out in that weather a lot.

 

[zoidberg]

Being located 'On the Clyde', penfold, you'll be aware of the expression 'The best-laid plans o' mice and men gang aft a-gley...'

 

[Poey50]

Caught out in 8 gusting 10 on a delivery we were bare poles; tied all our mooring warps together(about 200m in all, 20mm braid) and streamed them in a big bight with a waterfilled jerrycan on the end, worked quite well on a 40' light-ish displacement boat. Drogues are a waste of money unless you are an adrenalin junky and plan on being out in that weather a lot.

Summary: we cobbled something together and survived so that proves something.

 

[thinwater]

Thanks for such a comprehensive reply?

The listed displacement for my boat is 11,800 lbs so hopefully 14,000 lbs “heavy” is about right, but yes a few more cones would be an easy addition

I like the closed thimbles. None of the ones I have found on Google say whether they are 306 or 316, A2 or A4. But perhaps not critical in kit that is not permanently rigged.

Deploying the drogue is going to be an adventure. In an earlier life I worked on fishing boats: “shooting the gear” was one of the most hazardous activities. My JSD is flaked into a wide mouthed duffle bag. Fingers crossed.

Glad to hear the shackled three way joint is still up to standard. I’ll have a think about the soft shackles

As you say retrieving the JSD is another matter. Time and a bit of effort, prussiks and winches.

I am also thinking about strategies to protect my Aries from the bridle legs. At the moment I’m thinking of some sort of extendable fibreglass/carbon fibre rods.

But after all the thought and effort I hope never to use the JSD????

The one thing I don't understand is the implication that you have assembled the gear but not test deployed it. I hear that one a lot. Would you not, at the very least, go out on a breezy (not story) day and deploy it, perhaps bare poles but at full throttle? And then recover it? All under conditions where mishaps will not be serious, you can critique the performance, and modify anything that was problematic.

 

[Fascadale]

The one thing I don't understand is the implication that you have assembled the gear but not test deployed it. I hear that one a lot. Would you not, at the very least, go out on a breezy (not story) day and deploy it, perhaps bare poles but at full throttle? And then recover it? All under conditions where mishaps will not be serious, you can critique the performance, and modify anything that was problematic.

Absolutely agree. Planning to do exactly that after the boat goes back in the water. Looking forward to it.

 

[zoidberg]

It seems, from a quick search on Google Images, that many suppliers do 'closed thimbles' - e.g Ronstan, Premium Ropes - although intended for wire rope.

The British company S3i do them in A4 Stainless - Heavy Duty Closed Body Thimble in 316 Grade Stainless Steel A4-AISI

Now, I don't know whether there is any reason NOT to consider the use of such, but a query to some decent riggers - e.g. AllSpars, Jimmy Green Marine - and/or the company should provide a reliable answer, as could our 'pro testers' Thinwater and Neeves.

Then there's this:

Stainless Steel 316 Captive Thimble Marine Grade

Stainless Steel Marine offers a variety of stainless steel thimbles, including commercial, heavy duty, standard, mil. spec and fed. spec. They accommodate various marine and industrial projects. The Captive Thimble is made from Grade 316 Stainless Steel for corrosion resistance and durability. Its primary function is to hold the wire or fibrous rope “captive” while preventing chaffing, making it ideal for in-water boat towing applications.

 

[thinwater]

Actually, the most common use of tube thimbles here is Dyneema tow cable.

 

[Poey50]

It seems, from a quick search on Google Images, that many suppliers do 'closed thimbles' - e.g Ronstan, Premium Ropes - although intended for wire rope.

The British company S3i do them in A4 Stainless - Heavy Duty Closed Body Thimble in 316 Grade Stainless Steel A4-AISI

That's what I use for my 8mm Acera Amundsen.

 

[Roberto]

If one chooses a Jordan drogue type, besides chainplates, warp and splices some serious thoughts should be given to the cones resistance. Three cases I am aware of where the cones were destroyed, one reported on OCC Flying Fish (see attached picture of the page)


A second case during the 2017 Ostar storm, the link below shows a 49' Najad, pictures alone tell something about the conditions she endured, I met Keith the skipper and he said he also used a JSD, but it lasted just a few hours, all cones shredded
OSTAR - Barca superstite a Horta
Third example a Bavaria I met, they also reported "exploded cones".
They were all commercially made JSD; using spinnaker cloth would seem too weak, though in the picture above they seem to be made in normal dacron sailcloth.