Jordan Series Drogue experience

[leftbrainstuff]

Originally Posted by mikereed100

Disclaimer: This is an account of a single deployment of a JSD, with conclusions drawn by a troubled mind. As such, it is presented not as dogma, but as a basis for discussion.

We recently had occasion to use our JSD in force 9 conditions off the coast of Japan. We were eastbound 5 days out of Yokohama when we were overtaken by the remnants of TS Leepi, which had become a fast-moving extra-tropical cyclone. The wind was in the high 40's, gusting into the mid 50's with seas of approximately 5-7 meters. The boat was under autopilot, our speed was 9-11 knots under bare poles and, although an occasional breaker would push the stern around a bit, the boat was handling the conditions comfortably, taking the seas in a dignified manner off the starboard quarter,. However, as the wind continued to build, the boat began to plane on the gusts. The autopilot continued to handle it well but the sun had set, the wind was building and it was time to slow the boat. We had pre-rigged both the JSD and parachute anchor prior to leaving Japan. I chose to deploy the JSD rather than the parachute anchor as we were traveling in the same direction as the weather with 4,000 miles of sea room and I expected the gale to pass by us quickly. Deploying JSD off the stern was simply a matter of dropping the chain overboard. The drogue ran out smoothly and behaved brilliantly, slowing the boat to 3.5 – 4.5 knots as the stern lifted gently over the seas. We turned off the autopilot and settled in. The gale continued for 2 hours then began to abate. By sunrise the wind had dropped to a light breeze and we retrieved the drogue and carried on.

A few points are worth commenting on.

First, the forces exerted on the boat by the drogue were truly impressive. The pull from the JSD, while gradual, would cause us to stagger if we were not holding on.

Second, one often hears that a disadvantage of the JSD is that they are difficult to retrieve, but in this particular case we found it fairly easy. Before deployment I had rigged a long pendant to one of the bridle arms. When it came time to retrieve the drogue we simply led this line forward to the bow roller, released the bridle arms and motored slowly forward, pulling the drogue in by hand. The whole operation took about 15 minutes.

Third, and most surprising, was that when we retrieved the drogue in the morning we found that most of the cones had frayed badly, particularly those closest to the boat that, presumably, were subjected to the most stress and turbulence,. The leading edges were most affected, but the trailing edges were frayed as well. This was after only 2-3 hours of gale force conditions.

Fourth, I was a bit surprised at our speed while lying to the drogue. After reading many accounts of monohulls lying to a JSD I expected our speed to be around 2-3 knots. We averaged 4 knots, which may have contributed to the rapid degradation of the cones.

Things I will do differently in the future;

I will replace the nylon rodes with Dyneema (SK-75). I believe the elasticity of the nylon rode allowed the boat to acclelerate on the gusts before all the cones were brought into play and the boat could be slowed. Many believe the elasticity of the nylon is a crucial component of the drogues function, providing elasticity and decreasing shock loads as with a parachute anchor. However, in the case of a drogue, I believe that the elasticity of the nylon is unnecessary as the resistance of the drogue is limited by it's smaller surface area in comparison to a parachute anchor. Further, as the boat is moving the rode is under constant tension so there is no shock loading even as waves strike the stern. In addition, it is possible that an elastic rode may ultimately result higher loads on the boat. Recalling that Force = Mass x Velocity squared, the loads multiply very quickly if the boat is allowed to accelerate. I believe that, in our case, this contributed to the fraying of the cones closest to the boat. I will likely keep the nylon bridle arms, but only as they serve double duty as anchor bridles and docklines. (As an aside, our 22mm, 3 strand nylon bridle arms were both badly hockled. I will replace them with double braid nylon in the future.) Weight is another consideration. Our drogue consists of 167' of 3/4” and 167” of 5/8” nylon double braid, with 45' bridle arms and 20' of 10mm chain attached to the end. This is very heavy, bulky and clumsy to move around deck. When wet, it is more that I can manage without pain medication. Dyneema would be far less bulky and much lighter, particularly as it does not hold nearly as much water as nylon. When sized for equivalent strength, Dyneema single braid can be found for roughly the same price as Nylon double braid..

I will also consider adding more cones. We used 150 cones, the recommended number for a multihull our size, but I feel that the recommendations for multihulls, with their greater windage, may be not be conservative enough. We have about average windage for a bridgedeck saloon cat our size, but the JSD still allowed an average speed of 4 knots. This speed may have contributed to the rapid fraying of the cones.

When we rebuild the drogue we will reinforce the edges of the cones. This could be done either by hemming or gluing a strip of cloth to the edge with GM 5200 or similar. It is possible that a simple bead of 5200 along the edge could be sufficient. My wife put ours together from a Sailrite kit, which uses lightweight ripstop polyester for the cones without reinforcement. Had the gale lasted longer, it is conceivable that the cones could have failed completely. This gale occurred in the first week of a five week passage and, had we needed the drogue again, it would not have been available.

Good report.

Interesting observations about the kinetic energy and cone fatigue.

A 4 x increase in kinetic energy from 2 to 4 knots due to the velocity of the boat. It sounds like you experienced enough accel and decel motions to induce strain based fatigue into the load carrying elements.

If you were sizing components for 2 knots then this might explain the line wear and tear. Miners law kicks in and the ultimate tensile strength decreases over time. Testing some of the lines to failure against new line would confirm this hypothesis.

I wonder if the base of the cones was resonating and that led to the rapid failure. Like luff flapping.

You could test for that simply. Perhaps towing a single cone behind your dinghy with a go pro filming it from behind at different speeds. Might be a good validation test prior to use.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[Jim Cate]

Interesting observations about the kinetic energy and cone fatigue.

Here's some anecdotal evidence to support this theory:

We use a small series drogue when towing our 3.5 m RIB in order to keep it from surfing into our stern when sailing downwind in bigger seas. It only needs two cones of the regular size to accomplish this.

Our first construction used nylon ripstop, 1.5 ounce weight. They didn't last very long before becoming shredded. I believe this is due to us towing the dink at speeds of 6-7 knots, far faster than the design speed for a series drogue on a yacht. We then constructed cones of heavy vinyl coated fabric, and they have lasted for years and hundreds of miles.

So, in the example quoted above (and a very useful report it is!) I suspect that adding additional cones and reinforcing the leading edges of the cones (ours, btw, were hemmed... didn't seem to keep them from destruction in our case of severe overspeed) would help keep them intact for reuse. The combination of slowing the boat meor and reinforcing the wear areas should be a big improvement. Not an easy task, though, removing all of them, hemming and replacing!

Cheers,

Jim

[Yukon Cornelius]

Originally Posted by CarinaPDX

Yes there were many problems with the racing boats in the '79 Fastnet. One in particular was the failure of carbon fiber rudders, new at the time. But that is a bit misleading in that the main problem was lack of judgement by the skippers. Many kept sailing (or at least tried to) after being hit by the strong winds and building seas. Others abandoned their boats when they could no longer sail due to rudder or mast problems, and instead went into the flimsy liferafts. There is always a chance of things going really badly, but it is the response that determines the outcome.

Ted Turner won that race, although few remember. When he realized that the conditions were becoming dangerous he shortened sail and hove to, getting underway once the front passed. Good seamanship is what matters in the end.

Greg

Where did you read that? If he hove-to during that race, he'd never admit it. Ted's famous quote was "...we just kept going at 10 knots". Here is a great little movie that Gary Jobson just released about the '79 Fastnet:
30 for 30 Shorts: Ted Turner’s Greatest Race «

[CarinaPDX]

I read it in an article at the time and never forgot it. Interesting that the story is different now. Perhaps what I read was that the sails were shortened. In any event he reacted before conditions built too high, while those that didn't paid a steep price.

Greg

[tominny]

Regarding the fraying of the cones closer to the stern:

The cones are spliced into the main line with several length of webbing before the cone body and the again after the cone body. If the fore and aft attachments are closer to each other than the stretch of the line this would transfer the load onto the cones. Conceivably, this could contribute to their fraying where the load on the main line is highest, i.e. closer to the stern.

[morganhenry]

I have run across many mentions of using Dyneema line but not a description for how to splice the cones onto the line. Does anyone have experience with the particulars of splicing into Dyneema without a cover? Or suggested links? I have just begun to build a JSD using the Sailrite kit. Much thanks!

[estarzinger]

^^ we used dyneema rode on our series drogue. There is no real trick to attaching the cones . . . Just take each tape thru the single braid and then back thru a couple cm's away and then tie a stopper knot in the tape.

Regarding cone material . . . Unreinforced 1.5 oz spin cloth is simply too light. 3oz Dacron is rather better. And even with that it is nice (but a lot of extra sewing) to hem the edges

[morganhenry]

@estarzinger thank you for the prompt reply. Your response gives me pause. I'm about to start fabrication with the Sailrite kit but have a great deal of respect for your experience. If the Sailrite material is too light in your experience than it seems like a waste of a great deal of time to go forward with this project.

[estarzinger]

^^ is the sail rite kit really 1.5oz nylon? If so, ask them to cut cones for you from 3oz Dacron. The extra material cost is not much, and it can be done with the same plotter with the same cutting file, so they can surely do it for not much extra cost/effort.

1.5 oz will handle the "sailing" loads, but the edges with come apart, and they will occasionally tear as you pull them in. It is a huge sewing effort and then a big job to put them all on the rode. So you should get the right material in the first place.

Edit:mmm rereading your post, sounds like you already have the cones. Sorry. Not sure what you should do in that case. I can't quite think of a way to reinforce the edges if the tapes are already sewn on? Can you send it back and get them to make you a "stronger" set?

It (1.5 oz) will work for a "one time use", which is in fact the max most get . . . unless you are going to do a bunch of southern ocean. But after one serious use, you will probably find a bunch of cones that need to be replaced.

I like the sailrite guys. Some of their stuff is a bit under engineered for "extreme cruising" and they are not engineers. But call them and discuss it with them. They have always tried to "make things right".

[estarzinger]

Btw . . . Beth reminds me that I made a "tool" to help putting the tapes thru the dyneema rode. It was just a piece of welding rod (could also have been wire coat hanger) that I sharply bent over (in half) - poke the bent part thru the dyneema, stick the drogue tape in the bend/slot, and pull back thru. It was an early version of what has now become know as a "puller fid". You can buy them now commercially, and for tight jobs of the commercial ones have some merit, but for the drogue tapes the bent wire works just as well.

[MattGrant]

Hi Everyone,
Sailrite uses Maxlite 250 for the cones (years ago we also used a 1.9 oz Nylon). It is 2.65 oz. In our opinion it is the perfect Nylon cloth for this application. Please feel free to contact me if you have further questions at info@sailrite.com.
Best Regards,
Matt Grant
Sailrite

Originally Posted by estarzinger

^^ is the sail rite kit really 1.5oz nylon? If so, ask them to cut cones for you from 3oz Dacron. The extra material cost is not much, and it can be done with the same plotter with the same cutting file, so they can surely do it for not much extra cost/effort.

1.5 oz will handle the "sailing" loads, but the edges with come apart, and they will occasionally tear as you pull them in. It is a huge sewing effort and then a big job to put them all on the rode. So you should get the right material in the first place.

Edit:mmm rereading your post, sounds like you already have the cones. Sorry. Not sure what you should do in that case. I can't quite think of a way to reinforce the edges if the tapes are already sewn on? Can you send it back and get them to make you a "stronger" set?

It (1.5 oz) will work for a "one time use", which is in fact the max most get . . . unless you are going to do a bunch of southern ocean. But after one serious use, you will probably find a bunch of cones that need to be replaced.

I like the sailrite guys. Some of their stuff is a bit under engineered for "extreme cruising" and they are not engineers. But call them and discuss it with them. They have always tried to "make things right".

[joel383]

Thanks Matt for the reply!

[morganhenry]

Sorry for the confusion folks. I was just coming back to post a mea culpa - I had misunderstood estarzinger's comment about 1.5oz not being strong enough material, and assumed he meant the Sailrite kit. It was only after reading the Coast Guard report (on Beth and Evans Home Page) and talking with Matt at Sailrite that I realized my error. My plan is to make the Sailrite kit and heat seal the edges. I've read numerous accounts over the past couple of days on drogues being deployed and it seems that the failures tend to be fraying at the leading edges of the most forward batch of cones. With that in mind I am considering have a batch of cones made from a heavier material for the lead group. Again, my apologies for the confusion.

[acesails]

Ace Sailmakers has been using 5.4 oz Dacron , with a 3/4" hem wide end of cone, to manufacture the Jordan Series Drogue®.

Don was a great friend, met with him many times. Never heard him say drogue good for one use. In fact, he considered it as a piece of equipment that has to be absolutely reliable. Over time, we have increased fabric weight and quality to achieve this.

Jordan series Drogue ® is a registered trademark describing the series drogue invented by Don Jordan as designed and built by Ace Sailmakers, East Lyme, CT.


Thank you
Dave Pelissier
Ace Sailmakers
East Lyme CT 06333

[wsmurdoch]

One of the things that I noticed when I made my series drogue is that cones cut with with the seam edges on the bias of the fabric feel different from cones cut with their seam edges cut along the warp and fill. The stretch properties of cones cut with the two different fabric orientations are different.

The pattern for the cone fabric has the two seam edges 90deg apart. I could lay them out on the fabric any number of ways, but both edges along the bias or one edge on the warp and the other on the fill seemed most "logical". I have never run across this being mentioned.

Is there a right way, a wrong way, or does the layout of the pattern on the fabric not really matter at all?