|
|
05-04-2018, 18:15
|
#61
|
Registered User
Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,919
|
Re: Acquiring A Ready Made Series Drogue
Quote:
Originally Posted by estarzinger
I am aware of one -
|
Thanks, thats a good data point. Still the fact that it's only the one yiuve heard about says a fair bit. I suspect the most dangerous moment with a JSD would actually be after the wind starts to ease, in a confused seastate. You might start wallowing in the lighter airs and bigger seas and the JSD would get a fair bit of slack in it. Prehaps setting a bit of sail forward or even motoring slowly downwind might help keep tension in the system in this case.
All speculation on my part as I've never had to use mine. Always a standard drogue or forereaching/heaving too has been enough.
|
|
|
05-04-2018, 18:41
|
#62
|
Registered User
Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,919
|
Re: Acquiring A Ready Made Series Drogue
http://www.kimchowaroundtheworld.com...April2008.html Could it have been this boat? 40 foot not 47. Looks like he had a JSD. Not a lot of good info online.
|
|
|
05-04-2018, 19:16
|
#63
|
Registered User
Join Date: Jun 2010
Location: Easton, MD
Boat: 15' Catboat, Bristol 35.5
Posts: 3,586
|
Re: Acquiring A Ready Made Series Drogue
A chain is only as strong as it's weakest link. A JSD built to withstand a F11 or F12 will not be the weakest link.
Most likely we would never hear of a boat being lost while using a JSD, they would just disappear.
Designing it to handle worst case scenario and the expense that entails tends to discourage people from making a reasonable version of one. Not only that, but it shows a poor understanding of the total picture of all the factors at play. It's like having a 1/4" chain with one 3/4" link (JSD) and declaring you have it covered. I guess this is the first time most of you have heard this argument and it goes against all you have been told so it might take some time to digest it.
|
|
|
05-04-2018, 19:25
|
#64
|
Registered User
Join Date: Jun 2010
Location: Easton, MD
Boat: 15' Catboat, Bristol 35.5
Posts: 3,586
|
Re: Acquiring A Ready Made Series Drogue
Quote:
Originally Posted by Snowpetrel
Using a series drogue is the 'worst case' scenario, no point in lugging it around unless it is fit for purpose and strong enough for the 1 in 30000 wave strike.
|
Nearly all accounts of it's use did not involve survival conditions. It was used more for comfort and to allow crew to get below where it is safer and to get rest. Worst case scenario is not likely survivable in boats under 60', JSD or not.
|
|
|
05-04-2018, 20:14
|
#65
|
Registered User
Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,919
|
Re: Acquiring A Ready Made Series Drogue
Quote:
Originally Posted by kmacdonald
Nearly all accounts of it's use did not involve survival conditions. It was used more for comfort and to allow crew to get below where it is safer and to get rest. Worst case scenario is not likely survivable in boats under 60', JSD or not.
|
It seems like you have a very limited understanding of the ocean, and just how statistics around waves work.
The idea of making a series drogue for a moderate gale only is dangerous. In these conditions it's not really needed unless a rogue wave comes through, and in that case your weak version would fail, right when it is needed the most.
You need to understand that the 10% loadcase is without a breaking wave strike. Even in a bad storm this is the case most of the time. Sure the odd foamy crest will wallop you but although uncomfortable for the most part they are not a threat.
The 100% loadcase is with a large plunging or rolling breaker striking the boat, this is a rare event even in a nasty storm, but the energy from this can easily capsize a boat even in moderate gale conditions.
The idea that survival conditions are likely not survivable by boats under 60 foot is laughable. The majority of boats under 40 foot survived the 79 fastnet and the 98 syd-hobart. And if they had used series drogues chances are they almost all would have been ok.
|
|
|
05-04-2018, 20:23
|
#66
|
Registered User
Join Date: Jun 2010
Location: Easton, MD
Boat: 15' Catboat, Bristol 35.5
Posts: 3,586
|
Re: Acquiring A Ready Made Series Drogue
Quote:
Originally Posted by Snowpetrel
It seems like you have a very limited understanding of the ocean, and just how statistics around waves work.
The idea of making a series drogue for a moderate gale only is dangerous. In these conditions it's not really needed unless a rogue wave comes through, and in that case your weak version would fail, right when it is needed the most.
|
Really? I would have thought that you would know the difference between a moderate gale and F12 conditions. Rogue wave? From all accounts, they are only a figment of wild imaginations. Lets try and drop the juvenile straw man arguments and look at in a scientific manner.
|
|
|
05-04-2018, 20:27
|
#67
|
Registered User
Join Date: Jun 2010
Location: Easton, MD
Boat: 15' Catboat, Bristol 35.5
Posts: 3,586
|
Re: Acquiring A Ready Made Series Drogue
Quote:
Originally Posted by Snowpetrel
The idea that survival conditions are likely not survivable by boats under 60 foot is laughable. The majority of boats under 40 foot survived the 79 fastnet and the 98 syd-hobart. And if they had used series drogues chances are they almost all would have been ok.
|
The 79 fastnet was F10 conditions if I'm not mistaken. The boats with competent skippers did fine in it. Those that made mistakes paid the price.
|
|
|
05-04-2018, 20:51
|
#68
|
Registered User
Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,919
|
Re: Acquiring A Ready Made Series Drogue
I am not sure what sort of ocean sailing you have under you belt, but its not as simple as you seem to think. It's a whole complex scale of variables that defines each blow. Sea height, sea type, underlying swell condotions, current, duration etc all play a big part. Windspeed is only one part of the equation. So to deride the 79 fastnet as being only a force ten shows a fair bit of misunderstanding of the sea. A fully developed F10 can be very dangerous.
With modern comms boats seldom just disappear in bad weather. So the absence of examples of boats being overwelmed with a series drogue cannot be explained away by saying they just dissapeared.
To suggest that a proper series drogue is a waste of time in survival conditions because your boat is the weak link and you will die anyway is just plain wrong. Typically the crew are the weakest link in these conditions, and that is the biggest benefit of a Series drogue. To make one that will fail during the first big wavestrike is a very foolish idea.
|
|
|
05-04-2018, 21:06
|
#69
|
Moderator
Join Date: Sep 2014
Location: Channel Islands, CA
Boat: 1962 Columbia 29 MK 1 #37
Posts: 15,071
|
Re: Acquiring A Ready Made Series Drogue
Hey DH, you might check into reinforcing the leading edges of the cones... maybe I dreamed it but I could swear somewhere back there in an old thread someone said to beef them up... I'll see if I can find it....
__________________
DL
Pythagoras
1962 Columbia 29 MKI #37
|
|
|
05-04-2018, 21:15
|
#70
|
Registered User
Join Date: Jun 2010
Location: Easton, MD
Boat: 15' Catboat, Bristol 35.5
Posts: 3,586
|
Re: Acquiring A Ready Made Series Drogue
Quote:
Originally Posted by Snowpetrel
I am not sure what sort of ocean sailing you have under you belt, but its not as simple as you seem to think. It's a whole complex scale of variables that defines each blow. Sea height, sea type, underlying swell condotions, current, duration etc all play a big part. Windspeed is only one part of the equation. So to deride the 79 fastnet as being only a force ten shows a fair bit of misunderstanding.
With modern comms boats seldom just disappear. So the absence of examples of boats being overwelmed with a sseries drogue cannot be explained away by saying theu just dissapeared.
To suggest that series drogues are a waste of time in survival conditions because your boat is the weak link is just plain wrong. Typically the crew are the weakest link in these conditions, and that is the biggest benefit of a Series drogue. To make one that will fail during the first big wavestrike is a very foolish idea.
|
The absence of examples of JSD use in survival condition is testament to good weather forecasting and sound judgement. Anyone who thinks a JSD, sound boat and crew will save the day in hurricane force winds is sadly mistaken. There is a wind speed at which the boat will suffer constant and repeated knockdowns under bare poles unless the crew is smart enough to cut it off and that would be doubtful if they got themselves in that situation. Ships don't even survive those conditions.
Food for thought: The design of the JSD for "worst case scenario" is drastically inadequate anyway. Lets take an average 40', 20K pound boat. JSD says design for a 13K pound load but then says to use 7/8 double braid nylon. That has about a 25K pound breaking strength. When human life is at stake a factor of safety of 10 or more is suggested by rope manufacturers. That would require a minimum breaking strength of 130K pounds or 2" nylon double braid. That's about 1000 pounds of line. Apparently Jordan knew it wasn't feasible, or necessary to design for worst case scenario.
|
|
|
05-04-2018, 21:21
|
#71
|
Registered User
Join Date: Jul 2012
Location: Hobart
Boat: Alloy Peterson 40
Posts: 3,919
|
Re: Acquiring A Ready Made Series Drogue
^^ I think it might be time to make use of the ignore feature.
|
|
|
05-04-2018, 21:33
|
#72
|
Moderator
Join Date: Sep 2014
Location: Channel Islands, CA
Boat: 1962 Columbia 29 MK 1 #37
Posts: 15,071
|
Re: Acquiring A Ready Made Series Drogue
__________________
DL
Pythagoras
1962 Columbia 29 MKI #37
|
|
|
05-04-2018, 21:41
|
#73
|
Moderator
Join Date: Sep 2014
Location: Channel Islands, CA
Boat: 1962 Columbia 29 MK 1 #37
Posts: 15,071
|
Re: Acquiring A Ready Made Series Drogue
Quote:
Originally Posted by kmacdonald
The absence of examples of JSD use in survival condition is testament to good weather forecasting and sound judgement. Anyone who thinks a JSD, sound boat and crew will save the day in hurricane force winds is sadly mistaken. There is a wind speed at which the boat will suffer constant and repeated knockdowns under bare poles unless the crew is smart enough to cut it off and that would be doubtful if they got themselves in that situation. Ships don't even survive those conditions.
Food for thought: The design of the JSD for "worst case scenario" is drastically inadequate anyway. Lets take an average 40', 20K pound boat. JSD says design for a 13K pound load but then says to use 7/8 double braid nylon. That has about a 25K pound breaking strength. When human life is at stake a factor of safety of 10 or more is suggested by rope manufacturers. That would require a minimum breaking strength of 130K pounds or 2" nylon double braid. That's about 1000 pounds of line. Apparently Jordan knew it wasn't feasible, or necessary to design for worst case scenario.
|
This is also a useful reference:
Drogues | Victor Shane's Drag Device Data Base
__________________
DL
Pythagoras
1962 Columbia 29 MKI #37
|
|
|
05-04-2018, 21:49
|
#74
|
Registered User
Join Date: Dec 2009
Location: Bundaberg, Qld.
Posts: 2,192
|
Re: Acquiring A Ready Made Series Drogue
Quote:
Originally Posted by Pete7
|
Jordan Series Drogue Durability Problems
Published Mar 12, 2017 Updated May 30, 2017
Quote:
In the last few years there have been at least two well-publicized cases of series drogues, based on Don Jordan’s research and design, deteriorating after as little as ten hours’ use in strong gale and/or storm conditions. And who knows how many other cases have gone unreported.
The problem is that the cones fray at the edges, to the point that it is questionable whether the drogue would function as intended in another deployment.
That said, I need to make clear that, as far as I know, this problem has not resulted in any actual storm damage to boats.
This problem is of huge concern to Phyllis and me, both because we recommend the Jordan Series Drogue™ (JSD) as the ultimate storm survival device, particularly for short-handed crews, and because we own one ourselves.
Given that, I have had email conversations about the problem with:
Dave Pelissier, owner of Ace Sailmakers, manufacturer of the Jordan Series Drogue™.
Stuart Letton, owner of one of the drogues that deteriorated badly over a comparatively short deployment, albeit in a nasty blow in a nasty piece of ocean.
Roddy Coleman, principle at Ocean Brake, who make series drogues based on Don Jordan’s designs.
Tony Gooch, hugely experienced offshore sailor, including a single-handed non-stop circumnavigation via the Great Capes, who has deployed (and maintained) a home-built series drogue multiple times in very heavy weather. Tony also inspected serial-circumnavigator Jeanne Socrates’ drogue, the other publicized failure, and shared his observations.
Here’s what I learned, together with what Phyllis and I intend to do about our own JSD:
First off, it’s tempting to blame the manufacturers of these drogues, and I have to confess that was my first reaction; however, early in my research, I found pretty conclusively that so doing would be counter-productive. Here’s why:
While Don Jordan did extensive testing of his design and wrote about how it worked in great and convincing depth, he did not do much testing of the actual details of construction. That said, Jordan did do some tank testing—I quote from the report that Jordan wrote for the US Coast Guard:
Conclusions: This test clearly indicates that the durability of the series type drogue should be adequate for prolonged operation under severe storm conditions.
The test sample was intended for use in drag tests, not durability tests. The cones were rather crudely sewn and it is surprising and encouraging that they did so well.
It probably would be a good idea to sew a small reinforcing tape along the forward edge of each cone. This would reduce the possibility of tearing the material when retrieving the drogue over the transom of the boat.
So, Dave at Ace Sailmakers, and then others, started building drogue cones from light ripstop nylon, without seeing any need to increase the weight of the material, figuring that if this construction survived the tank test that it was the way to go.
That said, clearly it would have been better if they had followed the recommendation in the last sentence to hem the front edge. Still, their decision not to is understandable since, at the time, the problem standing in the way of wide adoption of Jordan’s invention was the high labour cost and extreme tedium involved in building the cones.
Adding hemming would have just made that worse. And, as it turns out, hemming probably would not have solved the problem, since it has now become clear that the 1.5-oz cloth weight was way too light to withstand multiple deployments anyway. And we should also note that Jordan only suggested hemming to withstand wear during retrieval.
Be that as it may, despite Jordan’s research and testing—the first serious science, as far as I know, ever done on the problem of improving storm survival using drag devices on offshore yachts—sailors (including me), being a conservative and generally parsimonious lot, just stuck with the less effective drag device technologies of the time.
It wasn’t until Dave at Ace Sailmakers grasped the nettle to build Jordan’s designs commercially that the JSD got out there in decent numbers and reports started coming in about how effective it was. And to get that market penetration Dave had to keep the cost as low as possible.
The point I’m making here is that we all owe Dave a debt of gratitude, not blame, as Jorden himself makes clear:
"I, Don Jordan, am writing this for Dave Pelissier because without him and his remarkable energy and dedication, the drogue would have rotted on the beach. Now its reputation has spread throughout the deep sea world, and I, now 89 years old, can be confident that it will continue to be available to sailors for the future"
So the next question becomes, why did the crude (Jordan’s description) tank-testing cones do as well as they did and others failed in the field? I don’t think we will ever know, but my guess, based on my sailmaking experience, is that the test cones may have been cut out with a hot knife, thereby sealing the edges, whereas the production cones were not.
Be that as it may, the answers to my email enquiries tell the story that, once more drogues were out there, reports started to come in of cone failures, particularly after multiple uses.
And, over time, Ace Sailmakers and Ocean Brake responded by:
1. Substantially increasing the weight of the cone fabric.
2. Changing from nylon to stronger Dacron.
3. Hemming the edges of the cones with tape.
And, as I understand it, drogues so built do not exhibit significant cone deterioration, even over multiple uses.
However, it’s worth remembering that in the course of a deployment the cones will be subjected to tens of thousands of collapse-fill cycles and so, over time and multiple deployments—unlikely for the average cruiser—some maintenance and repair is inevitable.
At this point, some will say that the manufacturers, once these failure reports started coming in, should have recalled all the original drogues and fixed them for free.
And I totally get that. For example, Stuart Letton was out some $2000 for, as he puts it, “a one-use drogue”, and was seriously (and understandably) pissed off.
But, on the other hand, sailmaking is not a very profitable game, at least for the small independent loft—even back in the day when I owned a loft, making a profit was hard, and the situation is way tougher today—so such a recall would have resulted in bankruptcy, not a fix. And further, would have pretty much guaranteed that no other manufacturer would ever come forward to make this vital piece of gear for fear of further business-ending recalls and/or liability.
I will say that Dave, and maybe others, could have handled the issue better and more transparently, but that’s hind sight, and I seriously doubt that I, faced with a potential business-terminating problem not of my own making, would have behaved any differently. When faced with an unsolvable problem, shutting up is a very human reaction.
Enough history, let’s move on to solutions. Obviously, there are a lot of variables here, so I can’t tell you what to do, but I can share how Phyllis and I plan to approach the problem of our own light-cone drogue and also discuss other courses of action we would take if our plans were different than they are:
On Morgan’s Cloud, our primary heavy-weather strategy is heaving-to, and therefore we have never used our JSD in anger, and given that we are getting older and our cruising is getting less aggressive, it’s not that likely that we ever will…touch wood.
That said, we bought and fitted our JSD to deal with the small but very real possibility that we could get caught out in a storm with breaking waves that would make heaving-to untenable, and that could still happen.
So we are going to:
1. Order a new first section with larger cones built out of Dacron to the new standard and hemmed.
2. Carefully use a hot knife to seal the edges of the remaining cones.
Our thinking is that, while there might be some deterioration in the old cones, we should get adequate drag from the combination of the new ones and the old, even in a long duration deployment. Also, based on our research, we think that maybe the cones at the boat end are more stressed due to surface turbulence than those further outboard.
While obviously we can’t know for sure—there is no for-sure in offshore sailing—we are pretty confident that this approach will meet our needs, particularly since the chances of multiple deployments in a single cruise are very low for us because our primary heavy weather coping strategy is heaving-to.
Step one has the additional benefit that we will have the replacement first section line built of Spectra—an option that was not available when we bought ours—which will reduce the weight (and bulk) of the whole system significantly, something our ageing backs will appreciate.
On the other hand, if we were say planning a high latitude circumnavigation via the Southern Ocean, where multiple deployments are likely, we would buy all new cones.
As I warned, not a definitive recommendation, but a good starting point for you to make your own decision on what to do.
That said, there is a caveat about cone replacement: Dave warned me that it can be difficult to replace the cones on a drogue that has been heavily loaded because the rope braid has pulled tight.
He also cautions that if you do decide to order new cones, make sure that they are made with the small end large enough to go over the splices joining each section, since generally, when new drogues are made, the splices are done after the cones are installed.
Before I wrap this up, all of this investigation did convince me that buying cones, even if we fit them ourselves to the line, is generally worthwhile, rather than sewing our own.
My thinking is that this kind of sewing is actually quite difficult to do well, and requires practice and the right machine. For example, details as small as having the thread tension set incorrectly can have big consequences.
I guess what I’m saying is, do you want the person building your cones to be doing it for the first time and learning on the job? No, me neither. And I would give the same advice to those fitting out with a brand new drogue.
That said, if your budget just won’t stretch to a bought drogue, home-building one is a heck of a lot better than not having one at all. Just be really careful to get the details right.
And that brings up one final point for those who buy a new drogue or are retrofitting an old one: Inspect each cone carefully and don’t hesitate to bitch at the manufacturer about any sloppy workmanship.
One more thing: I went to all this trouble to investigate the history of this problem because I believe that series drogues built to Don Jordan’s design are simply the best offshore storm survival system in existence, and should be carried by all short-handed crews heading offshore.
|
I suggest others sign up for "Attainable Adventure Cruising", costs bugger all and has a wealth of knowledge for the cruising yottie......
https://www.morganscloud.com/
|
|
|
05-04-2018, 21:50
|
#75
|
Moderator
Join Date: Sep 2014
Location: Channel Islands, CA
Boat: 1962 Columbia 29 MK 1 #37
Posts: 15,071
|
Re: Acquiring A Ready Made Series Drogue
I used to admire and marvel at that little Piver often when I was living in the SB harbor on my boat picking up trash during the days and working at the John Dory restaurant at night back in '79. Just the sight of that boat was inspiring to me as reckless kid... I remember hearing about the boat coming back from Hawaii, but never met Victor and didn't even know it was him till I read his book a while back! QME windvane! That was the high tech of the day!
Sorry for the brief thread drift....
__________________
DL
Pythagoras
1962 Columbia 29 MKI #37
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Rate This Thread |
Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|
|
|
|