Jordan Series Drogue experience

[NevisDog]

Originally Posted by estarzinger

.....you do have the option to add some elasticity in the bridle. .......

Great information. So, I'm about to make this decision; for those with experience, you seem to lean towards a preference for Dyneema leader and tail (is this a fair assessment?) but:
- which material do you personally prefer for the bridles?
- do you think Dyneema should be of slightly greater strength than the equivalent nylon (to compensate for reduced stretch) or not?

[UNCIVILIZED]

One thing which perhaps hasn't been mentioned here concerning the spectra debate, is that quite often a JSD on it's bridle alone won't be long enough to be fully 1-2 wavelengths behind the boat, due to the long wavelength of some ocean swells. And in some of the research done on drag devices including by Evans Starzinger, Beth Leonard, & the Dashew's, being able to link multiple sections of rode together has been suggested as a way to deal with this need for a longer overall JSD package.
So that I suppose if one were truly concerned about needing some stretch in the system, a nylon rode could be connected somewhere in the package, at some point between the drogue & the bridle, or the boat's drogue chainplates.

As to what effect it may or may not have I couldn't say. And too, at some point one may not have a choice in terms of what sort of rope to use for this, as only so much large diameter/high strength cordage can be carried aboard any vessel. So part of the "leader" between the JSD & the boat/bridle may wind up being one of your rope anchor rodes. Though I'd try & avoid using 3-strand rope due to it's twisted construction being a possible weak point from the aspect of it possibly hockling, with a resultant huge strength loss.

Some of the above info, & more, is covered in another thread on JSD's about cone shape & construction (materials). It's a fairly recent thread, as in maybe a few weeks ago, in case anyone goes hunting for it.

[estarzinger]

Originally Posted by NevisDog

- which material do you personally prefer for the bridles?

Our personal choice was dacron - lower chafe potential than nylon while better (less slippery) at winching and cleating than bare dyneema. Elasticity was not a big factor in this choice but it is between nylon and dyneema in elasticity - enough to take the edge off a transient shock load.

- do you think Dyneema should be of slightly greater strength than the equivalent nylon (to compensate for reduced stretch) or not?

I personally don't think so, but that is simply an 'educated opinion' rather than 'engineering based'. Practically speaking I would (and did) just 'round up' to the closest dyneema size. If you are sizing for the ballpark 'worst case loads' indicated by Jorden/Ace, you are really well covered for 'severe storm' conditions (where the loads are way less than in the 'worst case'). And my take from use and some limited testing is that the series by design will probably progressively loads and not transient shock load (much).

We don't know very much because the 'worst case' is so very very very rare - it is the 'difficult to know what to do' risk assessment pool with other 'known unknowns'. For cruisers on the 'normal routes' and paying attention to weather routing, even 'severe storms' (are encountered just frequently enough to fully understand and prepare for but) are pretty infrequent.

Originally Posted by UNCIVILIZED

is that quite often a JSD on it's bridle alone won't be long enough to be fully 1-2 wavelengths behind the boat, due to the long wavelength of some ocean swells.

yes, exactly. A 13 second wave period is not unusual and that will (in open ocean) produce (about) a 250m (820ft) wave length. We had the capability (and did when the conditions merited) to run 600ft drogue rodes . . . but you can see that may not even be 1 wave full length.

One of the reasons the series system is useful is that it functions better (than single elements and para's) when it is within the same wave as the boat.

The other thing to recognize about this is that a storm will contain a mix of wave lengths (and directions). It is not all one uniform wave pattern. There are some interesting tactical choices when running with a drogue in a system with two decent size wave patterns from different directions, and these tactical choices will (probably) change during the storm's development.

[thinwater]

In simple theory, farther back is always better. In reality, it is waves from off-axis that create the danger. Therefore, you want some drogues in the water within about 200 feet to provide some breaking when the waves are from an angle.

I personally cannot imagine dealing with Dyneema under load. The grip is horrendous and no sort of grab seems reliable. I would chose polyester for this reason alone. However, this could well be because I have not learned the right tricks.

[NevisDog]

Originally Posted by thinwater

... you want some drogues in the water within about 200 feet to provide some breaking when the waves are from an angle.

This came through clearly in the DDDB - too long a rode and there is no protection when hit by a breaking wave from the side, as the long rode then has soooo much slack. I think this was perhaps Jordan's whole point, in that the JSD still functions within the same wave trail, whereas any single drogue (or para anchor) is forced to the surface and can be hurled forward by a breaking wave.

"I personally cannot imagine dealing with Dyneema under load. The grip is horrendous and no sort of grab seems reliable. I would chose polyester for this reason alone."

Interesting - voice of experience instead of (me and others) theorising. But the other advantages are significant and now we must choose. I found the other thread Uncivilised mentioned and with the low-cost version of HMDPE now available, I'm tempted to go that way and worry about the increased difficulty of retrieving a much more slippery rope once the storm is over - I guess that's the only time handling really comes into it?

[UNCIVILIZED]

If one cares to look, there are dozens of discussions on this & directly related topics, going back at least a decade here on CF. Seaworthy Lass compiled a good list of resources in another JSD thread recently, including links to a few of them. But when I did a search on Dyneema Anchor Rodes, plenty of threads on JSD's, Dyneema, & Drogues in general, were listed along with the primary search header phrase.

I'm in agreement about being concerned about pulling in the drogue only after the storm has passed. Especially as Dyneema is several orders of magnitude lighter when "wet" than Nylon or Dacron. And I'd think that by throwing a couple of extra wraps around the winch to compensate for it's slipperyness, you could pull in the Dyneema by hand just as you would Nylon or Dacron. As winching it with a self tailer is out due to the cones. But gardening gloves with the heavy rubber palms & fingers add a huge amount of grip when handling lines. So plan on using a pair for this task. And they even help folks that have hand strength or dexterity issues, with regular, non-Dyneema lines.

[Dockhead]

Originally Posted by NevisDog

. . . Interesting - voice of experience instead of (me and others) theorising. But the other advantages are significant and now we must choose. I found the other thread Uncivilised mentioned and with the low-cost version of HMDPE now available, I'm tempted to go that way and worry about the increased difficulty of retrieving a much more slippery rope once the storm is over - I guess that's the only time handling really comes into it?

I'm a theorizer like you, since I've never used a JSD, so take this with a big box of salt, but I have not found single braid Dyneema so hard to handle. Yeah, it's slippery, but it works fine on a winch with a couple of extra turns. It's harder to get a grip on a smaller diameter line, of course, which compounds the slipperiness issue, but rope which is light and flexible is EASIER to handle in respects excluding grip. I love the lightness and flexibility of Dyneema, one reason why I have changed almost all of my running rigging to Dyneema.

Imagine a polyester double braid rope a couple sizes bigger, and soaked in seawater -- yeah, that's not so pleasant, either, is it?

[Mycroft]

Here are some pictures of my setup. The large blue eye was on a fishing boat and my inspiration for attachment points on my 20-ton double-ender.

The final attachment point installed with backing plates and 8 x 3/8" bolts.

The Ocean Brake deployment bag with my Ace Dyneema drogue in place. It rolls up like a sleeping bag and attaches to the bottom rung of the stern pulpit. The attachment thimbles are then attached to the plates and the end thimble is attached to my small stern anchor.

Not looking forward to the trial, retrieval, and restow.

[Seaworthy Lass]

Originally Posted by NevisDog

I found the other thread Uncivilised mentioned and with the low-cost version of HMDPE now available, I'm tempted to go that way and worry about the increased difficulty of retrieving a much more slippery rope once the storm is over - I guess that's the only time handling really comes into it?

I have found another source of low cost HMWPE rope: Stirotex from Premium Rope here in the NL. It is available unsheathed or with a polyester cover. Premium could not give me an exact price when I quizzed them about it at HISWA, but said it was roughly half that of dyneema.

Acera is still the winner price wise and is what I am planning to use for our series drogue. For those of you who missed it, this is the thread discussing Acera:
http://www.cruisersforum.com/forums/...es-190315.html

SWL

[SecondBase]

Originally Posted by DefinitelyMe

Wonderful post, thanks very much.

We lay to a single cone drogue in a force nine in the North Atlantic ten years ago that lasted for about 36 hours. Waves were ten metres. In that case, the nylon rodes (we had two rodes each led to one of the cockpit primaries) were indispensable I feel, however I can see the logic of your decision to replace with dyneema. Perhaps. My concern would be when the waves get bigger than the ones you experienced - we were getting picked up and thrown by some of them. The load exerted on the boat by the waves themselves was erratic, and would still be erratic with a series drogue I think. What we really need is shock absorption coupled with some form of rebound damping. Any ideas for that anyone?

DefMe -

Counter-intuitive but maybe add some more cones and then engine in gear ahead, slowly adding turns, until you hit rebound balance point?

[DumnMad]

Originally Posted by Seaworthy Lass

I have found another source of low cost HMWPE rope: Stirotex from Premium Rope here in the NL. It is available unsheathed or with a polyester cover. Premium could not give me an exact price when I quizzed them about it at HISWA, but said it was roughly half that of dyneema.

Acera is still the winner price wise and is what I am planning to use for our series drogue. For those of you who missed it, this is the thread discussing Acera:
http://www.cruisersforum.com/forums/...es-190315.html

SWL

Actually SWL, I get the impression that your boat has enough inertia(weight) and and crew experience to not need a drogue.

Are you plannining to circumnavigate the Antarctic?

[NevisDog]

Originally Posted by SecondBase

DefMe - Counter-intuitive but maybe add some more cones and then engine in gear ahead, slowly adding turns, until you hit rebound balance point?

This in response to:
"The load exerted on the boat by the waves themselves was erratic, and would still be erratic with a series drogue I think. What we really need is shock absorption coupled with some form of rebound damping. Any ideas for that anyone?"

The DDDB provides a vast amount of knowledge on this - many user reports under extreme conditions, highly recommended (though additional reports, like the OP's, are equally valid). My reading of it was (from memory):
1. Most single drogues are inherently erratic, diving and surfacing under load;
2. The series drogue provides both damping and shock absorption.
Consequently, the assumption that the load from a series drogue would be equally erratic may be quite incorrect. From earlier posts here, extra cones are only suggested for cats with unusually large windage? Adding too many cones is never recommended. (I hope that's a fair summary.)

[Seaworthy Lass]

Originally Posted by DumnMad

Actually SWL, I get the impression that your boat has enough inertia(weight) and and crew experience to not need a drogue.

Are you plannining to circumnavigate the Antarctic?

The challenge of Cape Horn is seductive

[UNCIVILIZED]

Originally Posted by Seaworthy Lass

The challenge of Cape Horn is seductive

SWL, as you've probably figured, I think that JSDs are probably one of the better bits of storm kit to have been created in a while. And reading the case studies on the DDB website is supremely educational. So I thought to pass along a nugget of info that I picked up there (& from other multihull sailors).

Which... is the motive force behind this post. In that whether you, or anyone else, is going to be rounding the Horn, or just doing a lot of offshore passaging. From where I sit, it only makes sense to have a Plan A, & Plan B, etc. for slowing the boat down & making her easier to steer. Or to sit out the worst of one of Neptune's ornery "moments".

Something which is mentioned with some regularity in the DDB. Especially as at times one's primary drogue may get irreperably damaged, or have to be cut away for some reason etc. And also that sometimes you don't want to slow the boat down quite as much as a JSD does. To which effect, some boats have multiple types of drogues onboard to match conditions. Be they commercial products, heavy warps, an old car tire, or all of the above plus a JSD.

On this, I'd be curious to hear stories from folks who've been out there in these kinds of situations, & their experiences as relates to the above & in general.

[Lantau]

Originally Posted by wsmurdoch

The two stern cleats are 10 inch with four bolts each. The metal backing plates are larger than the spread of the feet of the cleat. The displacement of a PSC 34 is 13,500lb. The design load for that displacement per Figure 26 of the 5/87 CG report is 11,200lb. Per p.59 the required fitting strength is 70% of that or 7,840lb or 2,000lb/bolt. Now, not knowing the alloy, not knowing how to handle the off axis loading, and not knowing the strength of the FRP layup or the ajoining structure, I called the maker. They said it would be okay.

I had a Pacific Seacraft. The cleats were very beefy and strongly backed. For a fiberglass production boat, I think that's about as good as it gets. This won't make sense to those with the more cheaply built fiberglass production boats. That said, I always found those cleats to be way too small for the way I used them. As I recall, I could only fit one line at a time, and not an overly thick one. Now I have a boat with massive bollards welded through the deck -- metal boat -- and welded again to the hull beneath the deck. Much better. My series drogue -- a very long and costly one -- will be attached to these.