Battle Testing a Jordan-Designed Series Drogue

Trevor’s voyage of 171 days, his first with a series drogue

In 2015 I bought a Jordan-type series drogue for Iron Bark, my 35-ft Wylo-class steel gaff cutter, designed by the inimitable Nick Skeates. She displaces 11 tonnes so the drogue is 97-metres long with 124 cones, as recommended. The drogue was supplied by OceanBrake.

“Iron Bark” in gentler climes off Tahiti

The cones are made of a heavy cloth with a rubberised backing, seamed all round with heavy tapes well sewn on. The bridle and first section of the drogue are 18-mm double-braid nylon with a tail of 14-mm nylon double braid. The splices, seizings and attachments of the cones are all strong, neat and seamanlike.

I thought the whole thing to be exceptionally well made and fairly priced.

Since fitting the drogue I have sailed from Scotland to Newfoundland and Labrador, then south down the Atlantic and around the Cape of Good Hope to Australia, and on to New Zealand, with a diversion to Australia’s tropical north coast along the way. During that time I used the drogue on six occasions. Here is what I learned:

The passage from Scotland to Labrador by the northern route, passing just south of Iceland, produced no wind above 45 knots, which Iron Bark rode out hove-to without resorting to the drogue. Similarly, there was nothing on the passage south down the North and South Atlantic that could not be dealt with by heaving to. It was not until I was south of 40°S and in the Southern Ocean that I first deployed the drogue.

First and Worst

About 435 nautical miles south-southeast of the Cape of Good Hope, in 41°S, 024°E, I ran into an eddy of the Agulhas Current that set northwest at between 3 and 4 knots. This was directly into the wind and predictably produced a lumpy, unpleasant sea. While the wind was moderate this was merely uncomfortable, but the barometer was falling.

The promised gale arrived just after dark and in 20 minutes the wind increased from south force 6 to west storm force 10 (25 knots to 45-55 knots). It was a scramble to strip all sail and run off downwind under bare poles.

The Aries wind vane was unable to prevent Iron Bark from broaching in the steep, breaking seas even after the wind eased to a gusty force 8-9 (35-50 knots), so I streamed the drogue for the first time.

Deployment

I used chain for the tail weight as it is easier to stow, deploy and retrieve than an anchor or a pig of lead

The drogue was stowed in a large sail bag with the weighted end on top and the two ends of the bridle showing. I hauled the bag onto the deck, looped the bridle legs over the bollards on Iron Bark’s quarters, dropped the weighted end overboard, and the whole thing ran out quickly. It is essential that it runs out cleanly since once the first few metres are in the water there is enough strain on everything for any snarl to be a serious matter.

I should have had this drogue years ago…

The effect was immediate; Iron Bark slowed from 3 knots to a little over 1 knot and ran steadily downwind with the rudder lashed amidships. Despite hard knocks from cross-seas there was no sign of broaching. There was nothing more for me to do so I went to bed; I should have had this drogue years ago.

Wind Against Current

Overnight the current dragged Iron Bark 27 miles directly into the wind although she was running downwind at over a knot—the average current was 3-1/2 knots. The effect of such a current on a gale-driven sea is better imagined than experienced.

Steering line

Before deploying the drogue I tied a stout rope to the junction of the bridle legs and the drogue leader. This third leg to the bridle is a lazy line that I kept under just enough tension to stop it fouling on anything without taking any strain. The line makes it easier to get the first few metres of the drogue in on retrieval, but its chief function is to allow me to steer across the wind by up to 30°.

An Interesting Modification

To steer across the wind I take the tension on the lazy line, slightly shorten the bridle leg on the side that I want to turn towards by taking another turn of the bridle around the bollard, then ease off the lazy line. The slightly asymmetrical bridle legs steer Iron Bark across the wind, letting her take cross seas on the quarters.

In the southern hemisphere the wind shifts abruptly from northwest to southwest on the passage of a cold front (warm fronts are almost unknown in the Southern Ocean). Running before the new southwest wind puts the old northwest sea abeam, which can be dangerous for a few hours until the northwest swell eases.

Taking the old sea on the port quarter and the new sea on the starboard quarter is safer and more comfortable. As the old sea dies away and the new sea builds up, course is altered to run more directly downwind by lengthening the shortened bridle leg. Lashing the tiller across helps, too.

Retrieving the drogue showing turning block forward

Retrieval

When the wind eased to 30 knots I set about getting the drogue back aboard. The system that I found worked best was to tie a retrieval line to the drogue with a rolling hitch, then lead that rope through a substantial turning block attached well forward and back to a cockpit winch. Using the winch for snubbing only (no winch handle), I got half a metre of drogue in as the stern dipped on each wave.

When the rolling hitch reached the turning block, I:

  1. belayed the drogue using a short line attached to the quarter,
  2. slacked off the retrieval line and hauled it and the newly-retrieved length of drogue aft,
  3. reattached the retrieval line with a rolling hitch,
  4. took up the slack on the winch,
  5. detached the short belaying line,
  6. and repeated the exercise.

A vessel of Iron Bark’s size gets 7 or 8 metres of drogue back on each cycle using this system; a larger vessel proportionately more, a centre cockpit vessel less.

Initially, I led the retrieval line directly to a cockpit winch. This had the lowest friction but meant the drogue streamed out almost abeam as I hauled it in, leaving Iron Bark rolling and lurching beam on to the old sea. Worse, I was trying to haul the boat sideways into the wind to get the drogue back—an impossibility.

Retreiving the drogue using the aft stanchion as a fairlead

So I led the retrieval line aft using the stern rail as a fairlead. This kept the drogue streaming astern and made hauling it in much easier. Using a stanchion or pushpit as a fairlead is fine on a metal vessel; a fibreglass or wood yacht might need to use something more substantially attached to the vessel.

Once the drogue was aboard, I flaked it into its bag ready to be used again, weighted tail end on top and bridle on bottom, but with the bridle ends showing and ready to attach to the stern bollards before deployment. Getting the bagged drogue down below was much harder than getting it out as the nylon double braid was now sodden and heavy.

Deployments Two and Three

I used the drogue on another two occasions before reaching Fremantle, each time in winds that were only sustained force 8 (35-40 knots), perhaps just reaching force 9.

As the wind was fair I would normally have run on under storm jib or bare poles in those conditions, but by this time I was over 100 days out from Newfoundland and Iron Bark’s bottom was so foul that the Aries could not cope, allowing her to broach repeatedly.

The drogue solved the problem of broaching at the cost of losing a day’s run each time.

Slight Deterioration

I inspected the drogue on arrival in Fremantle and found a couple of the cones were slightly frayed, but not enough to be worth worrying about. At this stage the drogue had had a total of 32 hours, a little more than half of that time in gale conditions.

From Fremantle I sailed north and spent the southern winter poking around northwest Australia before returning to Fremantle. The return passage entailed thrashing 1600 miles to windward (sailing 2800 miles to do so), not the best point of sail for a smallish gaff cutter, but with no weather that could not be dealt with by heaving to. During this time I built a deck locker for the drogue to eliminate the need to drag it up and down the companionway.

More Roaring 40s

In December 2016 I left Fremantle hoping to get around Cape Horn to the Falklands before winter set in, with the option of diverting to Tasmania or New Zealand if I was delayed.

The passage would be largely in the Westerlies of the Southern Ocean and likely to be a rough one. I was 900 miles southwest of Cape Leeuwin and south of 45°S before I found the Westerlies, but then they filled in with a bang and gale followed gale.

Although the first gale was only a sustained strong gale force 9 (40-45 knots) gusting 50 or 55 knots, I deployed the drogue, as much for comfort and to get some rest, as for safety. The wind dropped to below gale force after 12 hours but remained too strong for me to get the drogue back in for another 14 hours.

We were never heavily pooped…

The next depression was onto us within 24 hours and the wind quickly built to north-northwest violent storm force 11 (60-64 knots). I let the drogue out again and Iron Bark ran steadily on with no sign of broaching. The drogue sometimes held the stern down enough for the top of a wave to fill the cockpit but we were never heavily pooped.

The seas were huge, majestic and terrifying, and worthy of all that has been written about the greybeards of the Roaring Forties. They never cease to overawe me and are far bigger than anything I have ever seen in the North Atlantic.

Vane Gear Damage

Some were so big that Iron Bark almost becalmed in the trough. When that happened the tension came off the drogue, and on three occasions there was enough slack for one leg of the bridle to take a turn around the Aries servo paddle. Twice I managed to free it; the third time I was not quick enough and the whole lower leg of the Aries was torn off.

The shear coupling in the Aries paddle proved to be stronger than the shaft it was meant to protect; clearly a design flaw in the Aries. In the short term the loss of the Aries did not matter as it was not connected and the tiller was lashed.

After 18 hours the wind eased enough for me to start retrieving the drogue. It looked quite ragged with many cones frayed and some completely burst.

A Rethink

Having lost my self steering, I had to reconsider my route. Although I can get Iron Bark to steer herself on all points of sail without a self-steering gear this requires trimming the sails for balance rather than speed, which slows her down by about 1 knot. Getting around Cape Horn before the onset of winter was unlikely so I decided to divert to New Zealand.

I had barely made that decision before the next depression brought another force 11 severe storm. I deployed the drogue again, this time for 21 hours. We rode through it safely, but I thought we ran a little faster than previously, presumably because many of the cones were damaged. The drogue was certainly easier to retrieve because of the reduced drag from the damaged cones.

Damaged Cones

By this time three-quarters of the cones were moderately or severely damaged and the rest looked as if they would not last through another severe storm. This after 138 hours of use, a little more than half of which was in gale force or above—I cannot retrieve the drogue until the wind is below 30 to 35 knots, so there is a certain amount of waiting about in relatively benign conditions before I get it in.

Onward

Once clear of Tasmania, I turned north up the Tasman Sea and encountered three more gales before reaching Opua, New Zealand, 49 days from Fremantle. None of these gales exceeded force 9 (maximum sustained winds 45 knots) and Iron Bark rode them out hove-to without needing the drogue.

Failure Modality

The cones failed because they are made from a relatively coarsely-woven material with a rubber-like backing. The material relies to a considerable extent on this backing for its strength.

After a couple of uses the cones nearest the vessel and those immediately downstream of the join between the 18-mm and 14-mm rope (those subject to the most violent stress reversals) started to shed their rubberised backing.

After another spell of bad weather, all the cones had shed their backing and those in the high-stress zones had burst. After 138 hours of use, those that had not burst were on the point of doing so.

An analysis of the cone damage.
Vertical axis is the amount of damage on a scale of 1:5.
Horizontal axis is cone numbers starting with number 1 being the cone nearest the boat.
Click to enlarge.

These cones from OceanBrake are very well made of substantial material, fully hemmed and the tapes are well attached. None of the stitching failed; the failure was entirely in the material from which the cones are made.

It may be that no material commonly available can withstand the repeated stress reversals to which these cones are subject in the prolonged bad weather of the Southern Ocean. It is certainly a topic that requires further research.

A Good Response

On arrival in New Zealand, I contacted Angus Coleman of OceanBrake and he immediately offered to do whatever was necessary to repair or replace the damaged cones without charge.

I thought this very generous and asked him to supply me with 60 replacement cones, which I will alternate with 6.5-oz sailcloth cones that I am buying from Dave Pelissier of Ace Sailmakers. This will let me compare the two types of cones.

Not Looking For Trouble, But…

I do not go looking for bad weather and hope it will be a long while before I know which type does best in prolonged severe weather. However, heavy weather is common enough in the higher latitudes of the southern hemisphere (and I still have to get around Cape Horn) for it to be likely that I will have a chance to compare the two types of cones, whether I like it or not. I will report back if/when I do.

Problems and Possible Fixes

Vane Gear

Preventing the drogue from fouling the servo paddle on vessels fitted with a servo-pendulum steering gear is going to be different in each installation. The issue is only likely in the Southern Ocean, as waves large enough for a yacht to be becalmed in a wave trough rarely occur in the North Atlantic.

Attaching the drogue to chainplates that extend well aft of the transom may keep the bridle clear of the pendulum, but long chainplates are going to be subject to considerable lateral strains and require cross bracing. Various other solutions are possible; in my case it was to build a trim-tab self-steering gear that cannot foul, and to do away with the servo-pendulum entirely.

Cone Failure

The problem of cones bursting after repeated use is more intractable. The North Atlantic is a much less harsh place and the OceanBrake cones would probably last indefinitely in those waters. The same is probably true of the 6.5-oz sailcloth cones made by Ace Sailmakers, but I do not yet have any experience with them.

Perhaps there is no material commonly available that is able to withstand the punishment dished out by repeated deployment in the Southern Ocean.

Series Drogues Work

In summary, I think the series drogue is a valuable, perhaps life-saving, aid to small vessels in heavy weather. It is worth its considerable cost and the nuisance of its weight and bulk, despite the problem of the cones having a relatively short life.

I will continue to carry one and do whatever it takes to keep it in good shape.

Further Reading

Disclosure:

When I bought the original drogue from OceanBrake, I was given a discount. Similarly, the new cones bought from Ace Sailmakers were at a modest discount. I do not believe either of these discounts to be outside the normal range of commercial negotiations.

Publisher’s Disclosure

OceanBrake are long-term corporate members and supporters of this site who offer AAC members a discount.

Like what you just read? Get lots more:


Or:


Please Share

Meet the Author

Trevor Robertson

Trevor is an Australian who worked as a geologist for the minimum amount of time necessary finance his voyaging. Iron Bark is a 35ft steel gaff cutter that looks after Trevor in his wanderings. In return he keeps her in sails, cordage and paint that costs more per gallon than rum. Since he launched her in 1997, they have travelled widely, preferring little frequented coasts - Antarctica, Patagonia, Greenland, Labrador, but have spent time in the tropics too. Iron Bark may be the only vessel to have wintered unsupported in both Antarctica and the high Arctic.

32 comments … add one
  • Marc Dacey May 19, 2017, 11:28 am

    What an excellent and informative analysis, one drawn from a real life at sea in truly testing conditions. My takeaway, barring further reporting, is that drogues under the most trying conditions must be considered expendable safety gear, but offer so many advantages otherwise that this is an acceptable element of their use. As for the vane damage, there are some vanes where the paddle can be lifted up and out. Was this an option for you or was the vane still actively steering with the tiller otherwise lashed? I’m wondering if an autopilot could work under these conditions, particularly when otherwise driven under bare poles or perhaps just a reefed staysail?

    • Trevor Robertson May 19, 2017, 6:36 pm

      Hi Marc
      Regarding the drogue as expendable is perhaps a bit harsh, but it certainly is a high-maintenance item. A complete set of spare cones is probably a good idea for a long Southern Ocean passage, but unnecessary for the North Atlantic where the distances are less and the conditions not so severe.

      The vane damage issue is going to be different in every installation. In my case I believed there was a greater chance of fouling the paddle stub if I removed the paddle so left the paddle attached. The difficulty of removing the paddle while hanging head down over the stern in rough weather also played a part in that decision. The real problem was the Aries weak link failed to protect the paddle leg.

      There is little reason to have an autopilot or self steering connected while running with a Jordan-type drogue. The boat’s speed is too low for the rudder to be effective in overcoming the drag of all that rope and over a hundred cones. I lashed the tiller and left it at that. Although at times I had the tiller lashed off-centre in an attempt to bring the old sea on to the quarter, I believe that slightly shortening the appropriate leg of the drogue’s bridle had more effect on the course . As in all cases I shortened the bridle leg and lashed the tiller off centre simultaneously, I cannot be certain of what was more effective. I am a practicing coward and find working on deck in those conditions difficult enough to deter experimentation beyond the most essential so will probably never know the answer to that question.

      Yours
      Trevor

      • Matt May 21, 2017, 1:05 pm

        Thanks for these insights, Trevor. A bit of back-of-the-envelope math suggests that your system of steering by adjusting the bridle legs is doing most of the work, and the rudder’s barely contributing at all when the bridle legs are offset. Designing a good way to handle that offset into both the boat and the bridle seems like a very prudent step.

        I’d find it very hard to believe that there is no material that can withstand the punishment these cones see. More likely, the market’s so small that the best material just hasn’t been found yet. One candidate that comes to mind is the high-tenacity polyamide(6,6) that Invista makes for car air bags. Or whatever that fibre is that’s used to make the braided wrapping on fire truck hoses.

        • Trevor Robertson May 22, 2017, 12:20 am

          Hi Matt,

          Thanks for the input about the relatively small effect the rudder has on steering compared to having asymmetrical bridle legs. It is always comforting to have one’s crude first impression confirmed by a more rigorous analysis.

          Some method of shortening one or other bridle leg is a valuable addition to any Jordan drogue installation. How to do so is going to be different in every installation. Those with the bridle attached to the vessel by way of chainplates on the quarters may be able to do it by running the steering line through a block on the chainplate. There are a number of obvious problems that will need to be dealt with in such an installation, but a failure of the block should not be catastrophic. If the block or steering line fails, the ability to steer across the wind is lost when the bridle leg again takes up the strain, but the drogue continues to work as designed.

          I am sure you are correct that there is a better material available for making the cones for a Jordan drogue but I have no idea what that material is. I believe the cones fails because repeated stress reversals cause them to loose the binder upon which the cloth depends for much of its strength. After being subject to 100 hours or so of cyclic wave action, the strength of the cloth is reduced to the point where the cones burst. This is despite the fact that the strain on a 5inch (125mm) diameter cone is small.

          I know too little about the characteristics of modern fabrics to comment on which one(s) are worth investigating further. The critical characteristic is going to be the ability to withstand repeated stress reversals without loosing a significant amount of strength. I imagine it being as similar to the having a sail flogging for long periods without the fabric disintegrating, though this may be an oversimplification. If I am correct, this precludes Dacron with a high amount of filler as well as most high-strength sail laminates because they end up looking like a wet tea towel or delaminate and tear to ribbons if flogged for long enough.

          Any suggestions from anyone who knows more about modern cloths will be valuable.

          Cheers
          Trevor

          • Dick Stevenson May 24, 2017, 3:03 am

            I wonder whether the cones could be made out of webbing rather like mini Galeriders.
            Dick Stevenson, sv Alchemy

          • Ernest May 24, 2017, 7:21 am

            It would be interesting to test how cones made out of Kevlar worked. Despite the hefty price tag it might be viable to have the most-stressed cones (those near the boat) made from a different/better material.

          • Stein Varjord May 24, 2017, 10:07 am

            Hi Trevor

            There are several interesting questions here, and I assume you, and maybe even more, Angus of oceanbrake.com, have been pondering these and other questions for years.

            From reading here and other descriptions and storeys of use, I get the impression that fibre strength might not be the only critical issue here. Loads are apparently not close to breaking points of fibres, and repetitions also seem to be too few to explain the degree of the observed failures.

            Flogging sails have been mentioned. A flag is another example. The fibres do get punished by the flogging, of course, but what seems to be the mechanism of the destruction is that the fabric gets loose and falls apart. Much like most knots on a rope will also come loose if they get enough shaking.

            So, if we assume that good fibres​ are chosen, we’d look for a way to keep the weave stable when exposed to lots of flogging. Melting the edge and sewing it too was already done with these cones. The only way to get more stability seems to be either to partially melt the cloth, laminate it somehow, impregnate it somehow or to use some weave method that has locking knots as part of the weave. I have no idea if that exists.

            One more possibility is to make the cones from more rigid materials than cloth. Some sort of PEHD maybe? That might prevent flogging. On the other hand, it seems quite unpractical, probably impossible in actual use, but maybe they could be stored stacked in eachother or such. I just wanted to mention it. Maybe it triggers somebody’s imagination. 🙂

            Perhaps some intermediate method could have merit. What about having a few battens in the cones? Battened sails withstand flogging much better.

      • Marc Dacey May 21, 2017, 7:29 pm

        Thank you for the further elucidation, Trevor. Good points, all.

  • Eric Klem May 19, 2017, 2:11 pm

    Hi Trevor,

    Thanks for the excellent accounts of the use of your drogue. The durability problems seem unfortunate but if it makes such a big improvement in comfort and safety, occasional maintenance may be what is required as you suggest. Hopefully the ACE cones hold up better. This also makes me wonder how well normal drogues such as the Delta would hold up.

    I am curious as to why nylon double braid was used instead of something stiffer such as dacron or even dyneema? If I understand the design correctly, the give in the system comes from the cones pulling through the water and not stretch but that any stretch results in potential energy being stored in the system which can pull the boat backwards when the load eases causing the drogue to react more slowly on the next wave.

    Thanks.

    Eric

  • Trevor Robertson May 19, 2017, 6:39 pm

    Hi Eric,
    Until I try them, I have no way of knowing if the ACE cones will last any better than the Ocean Brake cones, but my first guess is that there will be little difference in longevity – I will let you know if/when I have had a chance to find out.
    OceanBrake uses nylon double braid rode because that is what Dan Jordan specified. I believe the reason for using nylon because it handles shock loads better than dacron, and the shock loads on the drogue in a storm are considerable. Dyneema was not generally available when Dan Jordan designed the system so he did not experiment with it, but may work. I have considered replacing the 14mm nylon tail section with dyneema to reduce the weight and bulk of the drogue but am reluctant to take the step. It is not cheap, but more importantly there is no going back on the decision in the middle of a severe storm if it does not work.
    I have no experience with single-element drogues, but over the past 20 years, whenever I have met anyone who has used a single-element drogue in the Southern Ocean, I have quizzed them on its performance. Some worked better than others but none seem to have lasted more than 12 hours in storm conditions (force 10 and above) before failing completely. That leaves us with some sort of series-element drogue system, and the Jordan-type seems to be the best of them.
    Yours
    Trevor

    • John May 20, 2017, 7:23 am

      Hi Trevor and Eric,

      I understand from Dave Pelissier at Ace that he discussed spectra as an alternative with Don Jordan towards the end of his life and that Jordan had no problem, based on his research, with that substitution. I also understand that Dave has made quite a few JSDs with at least some spectra and had good results.

      That said, I have not talked to anyone who has used a JSD made from spectra.

    • Eric Klem May 22, 2017, 2:25 pm

      Hi Trevor,

      Thanks for the reply, lots of good information.

      The combination of your, John and Angus’ comments on line material are interesting. I certainly would not want to be the first person to try a major design change in southern ocean conditions. It would be very interesting to examine the dynamic effects of stretch in the system. With a low-stretch line such as dyneema, the shock absorption capability would be lower. With high stretch, the load would ramp up more slowly and it might allow the boat to accelerate to a significantly higher speed before being pulled through the wave. I don’t have a handle on what the numbers are for this so can’t say anything more than that. Given that Jordan saw no issue with spectra, it is definitely intriguing although I hear Angus’ concern over cost.

      For several years, I have been somewhat bothered by how we try to do shock absorption on boats. We are pretty good at putting in springs such as nylon line but we are poor at putting in dampers. Watching a lot of boats anchored on long nylon rodes, it often looks to me like a car hitting a bump with worn out shocks where it keeps bouncing for a while due to underdamping. In the case of a JSD, the drogue itself represents a decent one way damper and the question is how to tune the spring.

      Eric

  • Scott A May 19, 2017, 7:00 pm

    Hi Trevor,

    Thank you for the detailed and informative chronicle of your experiences using the JSD. Since you mentioned you now intend to carry spare cones on passage, could you speak a bit more on the time required to replace damaged cones along the drogue? Is it a matter of splicing them into the line, or is there sewing involved? Much thanks!

    • Trevor Robertson May 19, 2017, 8:15 pm

      Hi Scott
      I have not yet replaced any cones so am speculating here, but I think it will involve sewing each cone up in place. I think (but do not know) that it will be better to carry the spare cones as flat arcs of cloth, The arcs hemmed with the tapes sewn on, but without the final seam to form a cone from the arc of cloth. The cloth elements can then be wrapped around the warp and the cone formed in place by sewing up the final seam. Lastly the tapes are hooked through the warp and knotted.

      My replacement cones have only just arrived in New Zealand and are at the opposite end of the country to me – a common problem with an itinerant life. I will post a comment once I have replaced some cones, but it may be a while before that happens.

      Regards
      Trevor

      • Scott Arenz May 19, 2017, 10:57 pm

        Trevor, thanks for your reply. I look forward to hearing about how the repair goes, so as to get the full picture of the life cycle of this type of equipment. Perhaps your experiences here will inspire further R&D in what fabrics can be used in the making of a JSD.

  • Bill Attwood May 20, 2017, 4:40 am

    Hi Trevor
    I read your report on your website a little while back. The best description of the use of a JSD anywhere. We built our JSD from scratch, and after threading 120 cones onto the line, I wonder why your replacement cones couldn’t be similarly threaded. I would have thought that hand-sewing each cone after wrapping it round the line would be difficult, time consuming, and would not achieve the security of a machine-stitched cone. I guess the problem might be that pulling a replacement cone over line plus existing cones is impossible. I’ll test my theory this evening.
    😉
    Yours aye,
    Bill

    • Trevor Robertson May 20, 2017, 6:38 pm

      Hi Bill,
      I hope you are right and the replacement cones can be threaded on to the warp. I will be very interested to hear the result of your experiment. I am impressed with your with the patience, tenacity and skill to make and assemble a Jordan-type drogue. I looked at the option and immediately ordered a ready-made one from OceanBrake.

      Threading new cones on from one end of the warp, as you suggest, is the first option I will try when rebuilding my drogue, for the reasons you outline. For a major refurbishment such as I need to do, I think it will be worth pulling or even cutting the splice at one end of each warp if that is necessary to let ready-made, machine sewn cones to slide over the warp end.

      Threading replacement cones on a spectra or dyneema warp should be comparatively easy as it will be over a much thinner line than a nylon warp. This is another argument for using a long-polymer warp in place of nylon.

      If replacing just a few cones at sea, it may be easier to unpick and resew the cones in place, but I have no experience with any of this. Until I get into the job, all I can do is speculate.

      Cheers
      Trevor

  • Stein Varjord May 20, 2017, 5:34 am

    Hi Trevor

    Great story and invaluable education! I have insignificant experience with drag devices and none with JSDs, but for some time I’ve considered the latter as essential gear. Your story has strengthened my conviction and made me more prepared to use it right. Thanks!

    About the fouling of the Aries vane or any other structure in the vicinity of the drogue legs, do you think covering them would be a solution? A canvas or other cover made to fit? Alternatively, maybe just a piece of rope or shock cord from the tip of the exposed item to som other points to stop the rope from coming around it? Spinnaker sheets have a maybe similar ability to jam anywhere and then destroy things when load comes on. On racing boats I’ve found shock cord works well. Any thoughts?

  • Trevor Robertson May 20, 2017, 6:55 pm

    Hi Stein
    Using rope or shock cord to deflect the drogue warp from projections around the stern may work. As always, it will depend on the details of each installation. I gave something similar some thought and decided it would not work on Iron Bark, but it may be effective on your boat. The difficulty of rigging lines over the stern in heavy weather also needs considering.

    I cannot imagine any installation where a canvas cover would work, but that does not mean it does not exist. Again the difficulty and danger of rigging covers is winds of force 10 (with seas to match) needs considering. The drogue is only going to be used in conditions that make doing any unnecessary work on deck is dangerous. The simpler the system the better.

    Cheers
    Trevor

  • Neil Simpson May 21, 2017, 7:07 am

    Hi Trevor
    Thanks for a valuable analysis of a piece of kit I’ve been considering for a while.
    Would a (anchor type) trip line make retrieval easier . . or am I missing something obvious ?
    Cordialement
    Neil

    • Trevor Robertson May 21, 2017, 8:12 pm

      Hi Neil,
      I cannot see any way of rigging a trip line on a Jordan-type drogue that will help retrieving it, other than a short line to the junction of the bridle and leader warp to get things started.

      A trip line to the weighted end of the drogue system will need to be at least as long as the total warp system, which means there will be at least 100 metres of rope streaming parallel to the drogue. This will inevitably tangle with the drogue warp. If by some miraculous chance it does not, hauling the drogue by its bitter end means dragging a huge bight of warp and cones through the water, requiring a far more effort than pulling it in from one end.

      Despite being neither particularly strong nor young, I found recovering the drogue took only about 3 hours of steady, but not exhausting, work. It is probably easier to retrieve the drogue in a seaway than in quiet water because the surge as each wave passes allows me to haul in half a metre or so of warp without undue effort.

      Regards
      Trevor

  • Bill Attwood May 21, 2017, 3:44 pm

    Hi Trevor,
    The test was successful. The JSD line is 20mm and 16mm double braid polyester, “20-fach geflochten”. Sorry but I can´t think of the right english words, but it is relatively loosely braided. I find the tightly braided lines impossible to splice. The lines are well above the breaking strain requirements for our boat, a Rustler 36, plus 1,500 Kg load. The lines have hard eyes at the front and back ends, and soft eyes for the join between (cow-hitched). I was quite surprised that the cones slid easily over the smaller hard eye, and of course, over the soft eyes. I didn´t try them over the hard eye where the bridle is attached, as that would be the wrong end anyway. The drogues are standard as defined by Don Jordan.
    The construction of the JSD was time-consuming but not difficult. Imke and I split the work between us. I made a template for the cones out of thin ply. It was important to make notches on the two perimeters where the tapes were to be sewn, and then to join up these marks before cutting them out. The Nylon came free as offcuts from our sailmaker. I marked them out with a felt-tip, then cut them with a hot-knife on plate glass. Imke sewed them on our Sailrite, using Prittstick to attach the tapes before sewing them. They were not hemmed. To my surprise, the most time-consuming step was the threading of the cones onto the lines. We made a record of the time involved in each step for our friendly sailmaker (he decided, unsurprisingly, that it would not be an economic business for him to offer the JSD). If anyone is interested I can look out these times.
    For the majority of sailors, the JSD would be seen as vastly too expensive, for those who need them, as your passage demonstrates, probably cheap at twice the price.
    It has occurred to me that the problem you experienced of the JSD fouling the self-steering because of the enormous waves might be eliminated if the weight at the end of the drogue was increased. Our JSD bridle is permanently attached to two chainplates, so we can´t play with the bridle lengths to adjust the boat´s aspect to the seas.
    Thanks again for your passage report.
    Yours aye,
    Bill

  • Trevor Robertson May 21, 2017, 8:14 pm

    Hi Bill,
    Thanks for taking the effort to give us that valuable input on drogue maintenance. It is reassuring to think I will not have to hand sew 124 cones to the warp. I am currently beating slowly south along the east coat of New Zealand towards where my new cones are being held, so will soon have a chance to find out for myself how to slide the new cones on to my warp.

    Thanks also for the offering the information on built times for the Jordan drogue. If anyone wants it, this is the obvious place to exchange that data.

    I think your suggestion that adding extra weight to prevent (or at least reduce) the slackness in the warp leader is sound. After demolishing the Aries paddle, I added 5 kg extra weight to the end in the form of a bit more chain. It was hard to tell how effective it was. The warp never fouled again, but of course there was no longer a servo-paddle to foul. It looked to me as if the bridle had less slack in the worst troughs, but that may have been because the seas in the next gale were not so large.

    Thanks
    Trevor

  • Bill Attwood May 22, 2017, 2:17 am

    Another suggestion for a cloth that might be better than ripstop is Hydranet from the German company Dimension Polyant. It’s not so easy to describe, but it uses two different PE strands woven on a special machine, one very fine and the other thicker, and works in a similar way to ripstop. Friends who use it as sailcloth are delighted, as it is extremely robust and holds its shape well. I have some offcuts and will sew up a couple of cones to see how easy it is to handle. But I have no idea how one might test it. It may be the case, as someone suggested in an earlier comment, that the JSD should be seen, at least in part, as a consumable.
    Regards
    Bill

  • Angus Francis Coleman May 22, 2017, 6:42 am

    Dear All,

    First, full disclosure, I made the drogue which Trevor talks about in his article.

    I’ll try and answer any points raised there, but also those here in the comments.

    Before all that I’d like to say that we offer a lifetime guarantee on our cones. If you have any issues, we will replace them free of charge.

    Bill and Trevor, the way we build our drogues means that it is actually fairly facile to thread new cones on. We do not put a splice in the end of each section, instead we have a figure of eight knot on a bight, which is then seized. Once this is removed, you can slide old cones off and new cones on with no difficulty. It is then fairly simple to replace the seizing and knot. Cone replacement need take no longer than 5 minutes per cone.

    Eric, we subscribe to the same approach Don had: If it isn’t broke, don’t fix it. As has been mentioned, dyneema wasn’t as readily available back then, and double braid nylon worked well in the system he designed. We offer dyneema drogues to those who ask for it, but given the price differential, roughly twice the price, we prioritise the double braid. When Jordan encouraged us to start making drogues, his aim was to ensure that they were available to all sailors who needed them, and unfortunately, dyneema drogues are incredibly expensive to produce.

    Marc, we are constantly looking for new and better fabric to build our cones out of. The current material has proven to be the best under the conditions we’ve tested it in. Going forward, we are looking at other polyester fabrics (un-resinated dacron).

    We have sold many drogues and had much feedback, and I have to say that Trevor is the exception rather than the norm. However, for all those who plan on sailing the southern oceans, we will be happy to work together to create a solution that will last.

    If anyone has any questions, please feel free to either reply to my comment or email me on info@oceanbrake.com I’m always happy to discuss storm survival issues, no purchase necessary.

    Angus

    • Marc Dacey May 23, 2017, 10:27 am

      Thank you for posting this. It’s a token of your investment in the rather unusual product you make.

  • Drew Frye May 22, 2017, 12:02 pm

    Just a few thoughts on the cone design. As I recall, Don considered his research into materials and construction far from complete.

    No resins or coatings. We all know that resinated cloth resists stretch better, but that the resin does not hold up to flogging. Additionally, when the resin begins to fail it is abrasive to the fibers. I would select a heavy, non-resinated cloth.

    Polyester has a MUCH (5x) longer fatigue life than nylon. Although there are impacts, they are minor, and it is fatigue over 100,000 cycles that matters. There are also high modulous fibers, but I don’t know enough about them to comment.

    What about 4 webbing straps? That would reduce the stress and flexing on the fabric by nearly 50% (it’s not linear). I don’t think there is anything magical about 3 straps.

    A JSD could be made with ~ 6-8 cones of developmental constructions. They could even be “extras” so that failure would not matter, although realistically, the selection of cone number is empirical anyway. Alternatively, build a substantial cyclical loading test rig, such as Jordan did. That was a smart thing, but he did not finish the research. This would be my natural inclination. I have built such rigs for chafe testing. Just a gear motor, a trough, some pulleys, and a weight.

    • Angus Francis Coleman May 22, 2017, 1:46 pm

      Hi Drew,

      As I’ve mentioned above, I’m looking into different polyesters, without any resins, for future cone construction. I’ve been trialing 4 straps vs 3, but haven’t seen any conclusive evidence either way. (yet!)

      A cyclical test rig is all well and good, but unfortunately no simulation ever covers all the eventualities suffered by cones in heavy weather usage.

      Any thoughts you might have on the matter are definitely appreciated.

      Kind regards,

      Angus

    • Stein Varjord May 22, 2017, 5:28 pm

      Hi Drew and Angus.

      On the topic of 3 straps. There might actually be a bit of “magic” about that number. 3 straps will be perfectly balanced in load. Like a chair with 3 legs, which will always have all legs on the floor, even if it’s very uneven. I don’t know if this is relevant in this context, though.

      The reason 4 straps give lower loads on the fabric is​, of course, that the loads are better spread so local peak loads get much lower. That could maybe be done other ways too. Maybe in how the webbings are attached? Maybe a reinforcement, like in sails?

      And thanks to Angus for participating here! It gives the discussion another level of usefulness. In my book, it also gives lots of cred. A maker who has an interest and keeps looking for improvement, is one I trust.

  • Drew Frye May 22, 2017, 7:03 pm

    As I check data, the fatigue life of polyester fabrics is actually many thousands of times better than nylon. You only use nylon when you really need stretch, and then you don’t expect it to last forever unless considerably (over 20x) over strength.
    https://2.bp.blogspot.com/-Fi_lgsXSs2U/UEkwMS4htAI/AAAAAAAABEo/8niFADj6Q6c/s400/rope+fatigue+life.png

    It also strikes me that the cloth weave was rather loose, dependent on the coating for structure.

    I don’t know if the rubber coated cloth was nylon or polyester, but those materials are generally nylon, because nylon stretches and moves better with the coating. But I am guessing.

    This is a tough problem, blending difficult engineering and a tiny market, with the need for compactness and reasonably simple construction to control cost. No criticism is intended, and it is clear that the vendors really care.

    • Angus Francis Coleman May 23, 2017, 3:57 am

      Hi Drew,

      The cloth we currently use, and in fact, the previous few iterations as well, is made from polyester.

      Angus

  • John May 24, 2017, 9:50 am

    Hi All,

    One thing that has struck me in reading the excellent comments to Trevor’s story, and particularly those suggesting ways to improve the longevity of the cones, is that we must be careful not to forget that Trevor’s level of use is extremely rare.

    Most of us will not in our lifetimes put as much wear and tear on a series drogue as he did in two voyages and therefore the present state of the art at both Ocean Brake and Ace will be fine for us.

    And further, let’s not forget that historically, and still to at least some extent today, the biggest barrier standing in the way of wide adoption of this boat and life saving gear is the expense, and/or extreme tedium involved in building it.

    Or to put it another way, let’s not let perfect get in the way of very good.

Only logged in members may comment: