3 strand polyester for a Jordan Series Drogue?

Gitane

Gitane

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I am making a Jordan Series Drogue for my Westerly Griffon which has a displacement of about 6000 lbs.

Most drogue I have read about use braid on braid polyester rope to hold the cones, but 3 strand polyester rope is cheaper.

Would attaching the cones onto appropriately sized 3 strand polyester be adequate? Is there a reason why 3 stranded rope should not be used?
 
It's preferred because it's easier to stow and (correct me if I am wrong) lower stretch?
 
The drogues Are threaded through the rope to secure them in place. The trouble with three strand rope is that the drogues will be pulled down through the strands of the rope as there’s nothing in the construction of the rope to stop it happening whereas the braided rope, with the drogues threaded through the strands of the braid, will not slip down.
 
Some of the 12 strand HMWPE lines (Dyneema is an example) are worth considering. They make the drogue much lighter (they are heavy for large boats which makes deployment more difficult ) and they take up less room. The reduced stretch helps the performance of the drogue.

This can be a more expensive option, but as thinner line can be used, if you source the HMWPE in bulk through fishing supply stores and use lines such as Acera it can be less expensive than braided polyester.

I agree three strand will not work.
 
To give you some idea of the difference the total weight of the line used (not including the cones or the weight at the end ) in the construction of our drogue would be 47kg in polyester and 7.5Kg in HMWPE (for our 49 foot boat). The HMWPE is also stronger has and much less stretch, less chafe and takes up less room.
 
noelex said:
Some of the 12 strand HMWPE lines (Dyneema is an example) are worth considering. They make the drogue much lighter (they are heavy for large boats which makes deployment more difficult ) and they take up less room. The reduced stretch helps the performance of the drogue.

This can be a more expensive option, but as thinner line can be used, if you source the HMWPE in bulk through fishing supply stores and use lines such as Acera it can be less expensive than braided polyester.

I agree three strand will not work.
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Recovery has proven a problem with Dyneema JSDs, ref a recent article on Morgans Cloud. The resolution proposed there is to add pre made stoppers into the JSD line giving nippers something to work against, otherwise they just slip under the tension.
 
I’d agree that a subscription to AAC is well worth while if you are thinking of JSDs.

I would not use three strand for a different reason - years ago I was shipmates with a traditional type sea anchor on a three strand warp. As the load came on, it began to spin like a top, as the warp tried to unlay itself under load, and then it stopped for an instant and started to spin the other way, and so on. I think a warp doing this would just wrap the series drogues round itself so that they became useless.
 
RobbieW said:
Recovery has proven a problem with Dyneema JSDs, ref a recent article on Morgans Cloud. The resolution proposed there is to add pre made stoppers into the JSD line giving nippers something to work against, otherwise they just slip under the tension.
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Thanks for the note. Let me stress I am no expert in drogue use.

I have not read the article by MC, but this is a known issue if you want to retrieve the drogue when conditions are still strong. This is also true for polyester, but the slippery nature of HMWPE does add to the problems although the line size is more appropriate for the winch. The difficulties are especially pronounced especially if you contemplate doing this single handed.

There are a few potential solutions. A retrieval line from the bridle junction to the boat is essential to help start winding the leader on a winch. It then helps to have a set up where large powerful winches can be used for the retrieval and where it is possible to feed the line around multiple winches to increase the friction.

The other problem to consider is drogues generate enormous forces when in use so the attachment points need to be considered very carefully. Chafe protection is also needed anywhere the drogue contacts the boat.
 
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Kukri said:
I’d agree that a subscription to AAC is well worth while if you are thinking of JSDs.

I would not use three strand for a different reason - years ago I was shipmates with a traditional type sea anchor on a three strand warp. As the load came on, it began to spin like a top, as the warp tried to unlay itself under load, and then it stopped for an instant and started to spin the other way, and so on. I think a warp doing this would just wrap the series drogues round itself so that they became useless.
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Thanks for the reply. but sorry, what is the AAC?
 
noelex said:
Some of the 12 strand HMWPE lines (Dyneema is an example) are worth considering. They make the drogue much lighter (they are heavy for large boats which makes deployment more difficult ) and they take up less room. The reduced stretch helps the performance of the drogue.

This can be a more expensive option, but as thinner line can be used, if you source the HMWPE in bulk through fishing supply stores and use lines such as Acera it can be less expensive than braided polyester.

I agree three strand will not work.
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Can you expand on the fishing supply stores and Acera?

Also would you not want stretch in your line?
 
gregcope said:
Can you expand on the fishing supply stores and Acera?

Also would you not want stretch in your line?
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We purchased our Acera through a commercial boat supply store (mainly the fishing industry) in the Netherlands.

The fishing industry uses miles of this stuff. The big help is that dyneema lost its patent a few years ago (at least that is my understanding) and so the number of companies (many of them very reputable manufacturers) producing these ropes has increased enormously. Many these are not interested in selling small quantities via yacht chandlers so it takes some searching to find, but given the advantages in series drogue construction it is worthwhile. HMWPE can be purchased from these sources often at a similar or lower cost than equivalent strength polyester from conventional yacht chandeliers such as Jimmy Green, but HMWPE was developed in the Netherlands so perhaps this is not valid everywhere.

It does sound wrong that stretch would be a bad property of the rope used in series drogue but all the evidence is in agreement that stretch is bad. Basically any stretch enables the boat to develop momentum when travelling down the face of a wave and then the drogue springs forward as the boat decelerates. The drogue itself has enough (too much?) inbuilt give because the cones will slip through the water.

Manufacturers offer the finished JSD with both polyester and HMWPE line (at higher cost), but recommend the latter.

Note: My wife is really the expert in this matter, but she does not contribute to this forum. I am only passing on the details I have absorbed from her in the hope that it is helpful. As these drogues are safety items it is important to have the best information.
 
I'd second advice about not using three strand because of the risk of it twisting the JSDs when deployed and the difficulty of flaking it for stowage and deployment. I used octoplait for my JSD to combat these complications.
The drogue and bridle for my 10m boat are manageable in octoplait. But I wouldn't want to be manhandling all that much more in the conditions that call for deploying a drogue. Worth looking into high modulus lines if your boat is above, say, 12m
 
The advice I had from oceanbrake was that you wanted some stretch as the loads could be considerable. Also Don Jordan recommended it.

I can see the attraction of HMWPE for weight, size and chafe resistance.

Any references for using HMWPE?
 
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gregcope said:
The advice I had from oceanbrake was that you wanted some stretch as the loads could be considerable. Also Don Jordan recommended it.

I can see the attraction of HMWPE for weight, size and chafe resistance.

Any references for using HMWPE?
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My information is the same. A dyneema drogue will potential impose huge snatch loads on the drogue and hence the chain plates (for the drogue) and the vessel - making it most uncomfortable even if nothing else. You need the elasticity to absorb the energy and smooth out those loads. If chafe is an issue then a dyneema bridle would suffice. If you down size, because you use dyneema it would be very difficult to handle by hand during retrieval. To me and advise from a cross section of parties suggests that dyneema is the exact opposite to what is needed and would be downright dangerous considering the loads on the chain plates. You could use a nylon bridle (and dyneema rode) but the loads on the bridle would also be huge and lifespan might be compromised.

Thinwater conducted some tests on drogues, he actually used a cross section of devices, his summary is in Practical Sailor - I'll see if I can find the link. I think drogues etc have been topics of discussion in Cruiers Forum a number of times, they have a good search engine.

There have been a number of articles in PS, referenced in the article linked below:

How Much Drag is in a Drogue? - Practical Sailor

If you make a very simple google search there are a number of references.

I think in addition to the drogue you need to seriously think of how/where you are going to attach the drogue and this has also been a topic of discussion (I think again on CF) and maybe here. But Thinwater has looked at the subject and once you have established how to build the drogue and what type then raising another thread specially focussed at the chain plates would be useful.

We have only been caught once sailing, across Bass Strait, once with winds of 55 knots. We were caught in a small low pressure cell, too small to be forecast, and we travelled in the cell, in the same direction and at a similar speed as the cell. . It is not pleasant, at all, and higher wind speeds would be awful. The vessel copes its the crew who are the weak link. Such conditions are best avoided. We did not use a drogue.

Jonathan
 
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Gitane said:
Hoping to cross the Bay of Biscay this summer. Weather and my nerve permitting.
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I asked because one chap I spoke to expected to sail in the southern N sea. The thought of a ship coming ( which would be quite possible in a very busy area) when he had a drogue out had me wondering if he had thought through how long it would take to get one of these things in.
I have never really studied them or their use, but if a ship did head towards one, then there is no way that a yacht could get out of the way.
A good watch & radar would, I imagine, be essential . And dare I say it- A handful of white flares - for the watch keeper who is half asleep.
Does the Bay of Biscay get that busy- i do not know? I assume one would be well outside & on a line that ships would use.
 
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