Acera vs Dyneema & Jordan Series Drogues

[Seaworthy Lass]

Originally Posted by UNCIVILIZED

I've seen those other pages, but it's been quite a while since I read them. So thanks for the links. IIRC there's more on drogues over on Attainable Adventure Cruising. And you're aware of the Drogue Device Database right? Victor Shane's Drag Device Data Base | Using Parachutes, Sea Anchors and Drogues to Cope with Heavy Weather – Over 130 Documented Case Histories
It has loads of after action reports from a multiplicity of vessels, & equally as many devices & techniques. Plus it's search feature is super handy.

I hear what you're saying about concerns regarding rope types for series drogues. I've read a few case stories where it was used, but nothing comes to mind right now. Though the fact that the Dashews carry a JSD built using Spectra line seems a good indicator, even if they've not used it in anger.

Also, in another, different thread on drogues, I related that on some boats, multi's especially, several different drogue types are carried. Some just for slowing the boat down while maintaining steerage towards one's destination. And another, like a JSD, for survival type conditions.
I picked up this info by reading some of the case studies/AARs on the Database (DDB).

And of course, one needs to use much heavier fabrics for the cones than was originally thought. As the loads they see during use tears up lightly built ones. Albeit due to the number of cones on a JSD there's a good bit of redundancy for if/when a few of them begin to shred. And having a much longer drogue, & also line to trail it with, than originally thought, is something which has become evident as a necessity. Especially given the wavelengths of some open ocean waves. Since they can be a lot longer than a 50m drogue can span or handle. And the ability to add extra lengths of rode to the drogue's towing line is a key tip that I recall Evans as having mentioned. Such as multiple fixed lengths of spectra linked together.


EDIT: I'm sure that the rope manufacturers like Samson, & Honeywell have data & info on real world use of Spectra/Dyneema in applications akin to JSDs. If naught else than in commercial towing. But on Samson's website alone, there are dozens of various maritime applications for their products. And in point of fact, something designed for commercial applications would likely be cheaper, & perhaps better suited for use in a JSD than is plain Spectra. So it couldn't hurt to contact them. Ditto on other folks that supply commercial maritime operators with cordage.

I hadn't seen the Drogue Device Database. That will be interesting to read. Thanks.

I am just starting to research these drogues. The additional links I found so far that were useful were from Morgan's Cloud's website and Sailrite (they provide a link to the US Coastguard report on these) and also Fatty Goodlander's general comments on drogues. I will look up the links for these in the morning and add them here.

SWL

[estarzinger]

Originally Posted by Seaworthy Lass

Is the insertion of the tapes staggered?

I don't know if anyone has an informed prescription on that, but we staggered ours primarily because it seemed easier to run them thru twice without potentially hitting the other tapes (rather than for any load spreading reason)


The load primarily seems to be on the point that the tape (with the stopper knot) emerges from the line.

I would guess that the loading has a big component of 'clamped' in the braid (like the Chinese finger) rather than all point loaded at the knot - remember the rope braid is being pulled tight by the total set of cone loading. But I don't know, never tested it. What I do know is that the tapes that are typically used are pretty weak. I would expect them to break at the knot way before the dyneema. And usually the cones break before the tape. So I would guess the dyneema is really unlikely to be the failure point - anecdotal experience would be consistent with that guess, but again I'v never seen it systematically tested - would be easy to do - you could do just with a decent size winch.

Did you use extra weight at the end to compensate for the fact that the dyneema floats, instead of sinking as polyester does?

We tried with and without weights. Ended up using without. It is easier to recover without, and does not seem to skip on the surface.

..........

[NevisDog]

So, now we have Acera... what a useful and interesting discussion.
(Posting to a thread is the only way I know to ensure I get updates

[JPA Cate]

NevisDog,

At the top of the thread is a button for a menu marked "Thread Tools". You can click on thread tools, and select "subscribe" or "unsubscribe" at any time.

Ann

[Benz]

I was given to understand that the patent on Dyneema has expired, which means other players may legitimately be getting in the game and producing the exact same product under a different name. Which is why we have to be careful of "Chineema," and do careful homework with all the SK- and AS- this and that.
But perhaps Acera has the same chemical composition as Dyneema. Whatever drives the price down without compromising quality is fine by me.

[Lantau]

I think you know this already, but do take great care when splicing this stuff. I would go way overboard when making the splices -- triple lock at least and stitch them like crazy. You don't want to use super-strong line with super-strong cones and so forth, only to have a splice fail.

But, again, I think you know this already.

[Benz]

Originally Posted by Lantau

I think you know this already, but do take great care when splicing this stuff. I would go way overboard when making the splices -- triple lock at least and stitch them like crazy. You don't want to use super-strong line with super-strong cones and so forth, only to have a splice fail.

But, again, I think you know this already.

Are you saying Acera splices differently than Dyneema? Or are you making a general observation for Dyneema as well? It's been my experience that the normally recommended bury--52 diameters, or 72 if you want a really elongated taper--is perfectly sufficient. I've been trying out shorter buries in places where room is an issue, and have never pulled out one that was one fid length (3 is the standard recommended for un-brummeled splices). But I've never seen Acera; maybe it's different.

[Dockhead]

Originally Posted by Benz

Are you saying Acera splices differently than Dyneema? Or are you making a general observation for Dyneema as well? It's been my experience that the normally recommended bury--52 diameters, or 72 if you want a really elongated taper--is perfectly sufficient. I've been trying out shorter buries in places where room is an issue, and have never pulled out one that was one fid length (3 is the standard recommended for un-brummeled splices). But I've never seen Acera; maybe it's different.

I was also puzzled by this. I've never had a Dyneema splice pull out. I understand that it is possible when a dyneema splice is flogged without having a load on it, but has anyone heard of an ordinary bury splice pulling out under load? I thought it was practically impossible. Am I missing something?

The Brummels and stitching add security when the splice is not under load, but under load they do nothing, isn't that right?

[Seaworthy Lass]

Originally Posted by Dockhead

I was also puzzled by this. I've never had a Dyneema splice pull out. I understand that it is possible when a dyneema splice is flogged without having a load on it, but has anyone heard of an ordinary bury splice pulling out under load? I thought it was practically impossible. Am I missing something?

The Brummels and stitching add security when the splice is not under load, but under load they do nothing, isn't that right?

As far as I am aware this is correct. I use 72x rope diameter for my buries and they hold like concrete. I put in a Brummel lock (or lock stitching in the case of a loop) simply so that the splice does not shake loose when load is released. This is of course more likely to occur underwater, so this precaution cannot be skipped for a drogue.

SWL

[Dockhead]

Originally Posted by Seaworthy Lass

As far as I am aware this is correct. I use 72x rope diameter for my buries and they hold like concrete. I put in a Brummel lock (or lock stitching in the case of a loop) simply so that the splice does not shake loose when load is released. This is of course more likely to occur underwater, so this precaution cannot be skipped for a drogue.

SWL

Were you ever concerned that the Brummel lock might actually interfere with the regular bury part of the splice from setting properly?

My splices are just like yours -- Brummel plus 72x bury -- and I have often wondered about the Brummel.

[Seaworthy Lass]

Originally Posted by Dockhead

Were you ever concerned that the Brummel lock might actually interfere with the regular bury part of the splice from setting properly?

My splices are just like yours -- Brummel plus 72x bury -- and I have often wondered about the Brummel.

I have seen nothing to be concerned about. I guess before any load has been applied to the lock, the outer portion of the spliced region of the splice has gripped and the lock itself is not given the chance to bear the brunt of the load.

After placing reference marks on the splice I have played around with applying load via winch with no lock in place and it is quite intriguing. There is no visible slippage before the splice grips.

[NevisDog]

Originally Posted by estarzinger

..........We tried with and without weights. Ended up using without. It is easier to recover without, and does not seem to skip on the surface.

I was kinda shocked by this comment, then forgot about it among all the other useful stuff here. Just so there is no misunderstanding, you are stating there is no need to weight a JSD - right?

[Lantau]

Originally Posted by Benz

Are you saying Acera splices differently than Dyneema? Or are you making a general observation for Dyneema as well? It's been my experience that the normally recommended bury--52 diameters, or 72 if you want a really elongated taper--is perfectly sufficient. I've been trying out shorter buries in places where room is an issue, and have never pulled out one that was one fid length (3 is the standard recommended for un-brummeled splices). But I've never seen Acera; maybe it's different.

I think anyone thinking about this a lot and with such experience is just fine. I was just saying...

But let's not forget that this is for a drogue. It has to be very strong indeed. And it won't be under load most of its life. It'll be in a bag in a locker for years, possibly shaking about from time to time. Perfect conditions I should think for a slippery splice (which is my characterization of a Dyneema splice) to worm its way out if not stitched. Even when deployed it might go from no load at all at the splices to maximum load quickly.

I've used Dyneema and like it very much. I replaced lifelines with it and would do that again. The splices are dead easy after the first couple. But I wouldn't trust a splice that's not locked and stitched. Just me; better safe than sorry.

[UNCIVILIZED]

Lock stitching splices is pretty much the norm, so I'm uncertain why it's being stressed so much. Or causing folks to stress over it. And as soon as the drogue hits the water, there won't be any periods of time where the splices won't be under stress. Kinda' common sense there.

[hellosailor]

SWL-
After all this time have you not asked the vendor/manufacturer directly your questions?
The mention of being ISO certified always impresses me, but a simple direct question such as "What is the national origin of the fibers themselves?" should get a direct answer. As an unreasonable New York native, I would say a direct answer within one business day, 24 hours, and two days only if there's a damn good excuse like too many time zones.
No answer within the week, means find another source, you're not dealing with business people, you're dealing with the worst sort of clerks.

And if they are really pro's, they should be able (in THIS business) to perform a load test on a particular spool, and send along certifications that it meets or exceeds the specifications. For a price, yes, but there are in fact rigging suppliers who offer to do that for all their customers, because even as suppliers, they know that THEIR suppliers may be cheating. (Nothing new there, the original cables supplied for the Brooklyn Bridge were so short of spec, it would have quickly collapsed.)