Acquiring A Ready Made Series Drogue

[kmacdonald]

Originally Posted by Don C L

This is also a useful reference:
Drogues | Victor Shane's Drag Device Data Base

I have read it and posted a link to it in the other JSD thread you linked above. They were mostly F8 to F10 experiences with the JSD. One F4-F5 experience. No survival condition experiences. Like I said before, I don't think anyone that has used a JSD in hurricane conditions is here to talk about it.

The force of the wind is a function of the wind speed squared. If you double the wind speed the force is quadrupled.

[thinwater]

Originally Posted by kmacdonald

... 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.

Actually, your analysis is not consistent with a full understanding of engineering practice. For example, ropes used for climbing and at-height access are rated at about a 12:1 safety factor for normal use (including routine short falls), but only at about 2:1 safety factor for a worst case fall. At 2:1 the rope can withstand at least a few dozen hits. Thus, his analysis is quite conventional. Whether it is correct is what we argue about. But it is normal engineering practice.

If you do not want to build a JSD for worst case conditions, you don't need a JSD. It would be much simpler, cheaper, and more veritile to use a single element drogue (Delta Drogue, Sea Brake, Gale Rider, Shark) in those conditions. Thus, there is no rational for building a lesser JSD.

[kmacdonald]

Originally Posted by thinwater

Actually, your analysis is not consistent with a full understanding of engineering practice. For example, ropes used for climbing and at-height access are rated at about a 12:1 safety factor for normal use (including routine short falls), but only at about 2:1 safety factor for a worst case fall. At 2:1 the rope can withstand at least a few dozen hits. Thus, his analysis is quite conventional. Whether it is correct is what we argue about. But it is normal engineering practice.

If you do not want to build a JSD for worst case conditions, you don't need a JSD. It would be much simpler, cheaper, and more veritile to use a single element drogue (Delta Drogue, Sea Brake, Gale Rider, Shark) in those conditions. Thus, there is no rational for building a lesser JSD.

Comparing "engineering practice" of climbing ropes with the design of a JSD is consistent but not what the line manufacturers recommend. It's not feasible to do so, so it isn't done. Not with climbing ropes or the JSD. It should also be noted that climbing ropes need to be light and weight would be a much bigger consideration than in a JSD. It's like comparing apples with oranges, they are both fruits but that's as far as it goes. In engineering terms, there are different design considerations. It should also be noted that climbing ropes aren't subjected to constant cyclic loading like a JSD.

There is every reason to degign and build a JSD for the conditions it is reasonably expected to be used in. That's what engineers do. Weight, bulk, stowage, ease of deployment all have to be considered. I have yet to see a report from anyone that used the JSD in survival conditions although someone here heard of one. Most reports are or use in F9 conditions or less.

I don't know about costs for the other devices but a 100 cone JSD with 3/8" dyneema can be made for about $700. Cones pre-made.

[MartinR]

Originally Posted by kmacdonald

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.

I also thought so before, but actually, ESA managed to find these from space with the ESR satellite. And they are actually fairly frequent.

[MartinR]

Originally Posted by kmacdonald

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.

This disaster is probably also attributable to the boats themselves. The IOR rule did unfortunately produce boats that were neither very seaworthy nor fast. At least in the smaller sizes. And I doubt most of the skippers had ever experienced a storm.

Conditions were a Force 10, but combined with the wave train hitting the continental shelf and a wind shift producing cross-seas made for appalling conditions.

[Snowpetrel]

https://www.morganscloud.com/2017/05...series-drogue/

A good JSD tale with an honest force 11 written by a very experianced seaman.


https://www.morganscloud.com/2013/06...ue-deployment/

Another tale of surviving what sounds like force 12 conditions with wind over tide.

Sounds like in both cases the engineering is pretty good (with the exception of cone wear), and the benefits are significant in severe seastates.

[Dockhead]

Originally Posted by kmacdonald

I have read it and posted a link to it in the other JSD thread you linked above. They were mostly F8 to F10 experiences with the JSD. One F4-F5 experience. No survival condition experiences. Like I said before, I don't think anyone that has used a JSD in hurricane conditions is here to talk about it.

The force of the wind is a function of the wind speed squared. If you double the wind speed the force is quadrupled.

It's clear you don't have any experience with weather in ocean conditions. You should really read and pay attention to what Estarzinger and Snowy Petrel write -- between them they have thousands of miles in Arctic, Antarctic, and Southern Ocean conditions and they know what they are talking about.

Wind is not the issue; it's sea state. F9 is already enough to generate life threatening (for even large yachts) sea states if it blows long enough over enough fetch. My experience compared to their's is minor, but I have been caught by a large breaking wave in the North Sea in a F9 which knocked down my large and immensely seaworthy vessel of 20 tonnes light ship. A smaller vessel might have easily been rolled and destroyed by that wave. F9 is enough -- again, if it's real ocean conditions with thousands of miles of fetch and a storm lasting long enough -- to generate sea states which can roll a seaworthy boat. F10 blowing long enough over a long enough fetch is already survival conditions. Hurricanes are not by any means the only dangerous weather events in the ocean, and certainly not in the high North Atlantic.

[Dockhead]

Originally Posted by MartinR

This disaster is probably also attributable to the boats themselves. The IOR rule did unfortunately produce boats that were neither very seaworthy nor fast. At least in the smaller sizes. And I doubt most of the skippers had ever experienced a storm.

Conditions were a Force 10, but combined with the wave train hitting the continental shelf and a wind shift producing cross-seas made for appalling conditions.

Actually Fastnet 79 was a Force 9 -- the "maximum wind speed was Force 10" which is not the same as F10 conditions.

But you are right -- many of the boats were marginally seaworthy, first of all, but secondly, and most importantly, the sea state was horrendous -- absolutely survival conditions, with 1/3 of the boats knocked down, 4 sunk, 1/4 rolled. Breaking seas of any sort, higher than the beam of the boat, are "survival conditions" for yachts, and F9 is quite enough to generate these conditions.

Skipper experience had little to do with it. This varied, of course, but most were highly experienced and more skillful than you or me. Most of them were English Channel sailors -- as hard a school of sailing as there is outside of, maybe, New Zealand. There is only so much you can do -- if you don't have a drogue or a sea anchor -- when you encounter breaking seas, higher than your own beam. If you don't have a drag device or sea anchor, you run off and try to steer out from under the big breaking ones -- I've been there, and done that -- but it's a numbers game, and the best skipper will get caught out eventually, when it's that bad.

[MartinR]

In my experience, the North Sea is a much worse sea area, because the waters are shallow and make for very steep and breaking waves. Comparable, North Atlantic waves are higher, but much longer. The worst wave I ever experienced was just in the North Sea. 35000 tons of ship at 3 knots, and it felt as if we had hit a concrete wall. I would not worry too much about the North Atlantic. You have a big, seaworthy boat. I have been out there sailing in storm conditions several times (when I was younger and crazier) and it is impressive more than frightening. The North Sea gives me the shivers.

The most important thing for me is to hand steer the boat in bad conditions. Outside, where you can see, hear and feel what is happening. I think many of the knock-downs experienced are due to autopilot steering. Autopilots can not anticipate anything, humans can. If you prefer the autopilot to steer for convenience, I think a series drogue is actually a good idea. Otherwise, personally I would not bother.

[Dockhead]

Originally Posted by MartinR

In my experience, the North Sea is a much worse sea area, because the waters are shallow and make for very steep and breaking waves. Comparable, North Atlantic waves are higher, but much longer. The worst wave I ever experienced was just in the North Sea. 35000 tons of ship at 3 knots, and it felt as if we had hit a concrete wall. I would not worry too much about the North Atlantic. You have a big, seaworthy boat. I have been out there sailing in storm conditions several times (when I was younger and crazier) and it is impressive more than frightening. The North Sea gives me the shivers.

The most important thing for me is to hand steer the boat in bad conditions. Outside, where you can see, hear and feel what is happening. I think many of the knock-downs experienced are due to autopilot steering. Autopilots can not anticipate anything, humans can. If you prefer the autopilot to steer for convenience, I think a series drogue is actually a good idea. Otherwise, personally I would not bother.

No argument from me -- the North Sea in a blow SUCKS. And it blows all the time. German seamen have an old saying -- "Nordsee ist Mordsee" -- the North Sea is the Murder Sea.

But the Western Approaches, really, are not less fearsome. This is where all the weather tracking the jetstream and the Gulf Stream over thousands of miles converges at the edge of the continental shelf -- it's some chit. Outside of the Southern Ocean, I'm not sure there's a more dangerous piece of water. You say correctly -- the big Atlantic waves don't break as readily. But they are higher, and when they break -- watch out.

[MartinR]

Originally Posted by Dockhead

Actually Fastnet 79 was a Force 9 -- the "maximum wind speed was Force 10" which is not the same as F10 conditions.

But you are right -- many of the boats were marginally seaworthy, first of all, but secondly, and most importantly, the sea state was horrendous -- absolutely survival conditions, with 1/3 of the boats knocked down, 4 sunk, 1/4 rolled. Breaking seas of any sort, higher than the beam of the boat, are "survival conditions" for yachts, and F9 is quite enough to generate these conditions.

Skipper experience had little to do with it. This varied, of course, but most were highly experienced and more skillful than you or me. Most of them were English Channel sailors -- as hard a school of sailing as there is outside of, maybe, New Zealand. There is only so much you can do -- if you don't have a drogue or a sea anchor -- when you encounter breaking seas, higher than your own beam. If you don't have a drag device or sea anchor, you run off and try to steer out from under the big breaking ones -- I've been there, and done that -- but it's a numbers game, and the best skipper will get caught out eventually, when it's that bad.

I think also fatigue was a major factor in this. Easy to make bad decisions under these conditions, and many people did. Just the sound is extremely stressful, not to speak of the movement of the boat and the anticipation of disaster. I agree that most of the skippers in this race were experienced, but I think very few of them had ever met conditions like these.

I agree that if the conditions are bad enough it is a numbers game. The best thing you can do is try to better the odds.

[Dockhead]

Originally Posted by MartinR

I think also fatigue was a major factor in this. Easy to make bad decisions under these conditions, and many people did. Just the sound is extremely stressful, not to speak of the movement of the boat and the anticipation of disaster. I agree that most of the skippers in this race were experienced, but I think very few of them had ever met conditions like these.

I agree that if the conditions are bad enough it is a numbers game. The best thing you can do is try to better the odds.

Indeed! But fatigue is ALWAYS an issue in an ocean storm. It may blow for days at a time. What is manageable with intense effort for some hours, might not be manageable at all, for days.

A full and well organized crew is a huge factor in getting through something like this. The limitations of single handed or double handed sailing very quickly make themselves obvious in a serious ocean blow.

And a drogue may be a life saver exactly for this reason -- you are in conditions which are somewhat mangageable with really active helming, but it wears you down after a certain period of time. Putting the drogue out and putting on the pilot might save you just from the point of view of fatigue.

[MartinR]

Originally Posted by Dockhead

And a drogue may be a life saver exactly for this reason -- you are in conditions which are somewhat mangageable with really active helming, but it wears you down after a certain period of time. Putting the drogue out and putting on the pilot might save you just from the point of view of fatigue.

Agree completely! And it also might save you from piling up somewhere, as the boat can move much slower through the water than when you are actively steering her.

A few more posts, and i might be convinced to buy a drogue also

[kmacdonald]

Originally Posted by Dockhead

It's clear you don't have any experience with weather in ocean conditions. You should really read and pay attention to what Estarzinger and Snowy Petrel write -- between them they have thousands of miles in Arctic, Antarctic, and Southern Ocean conditions and they know what they are talking about.

WOW!!!! Can't believe you said that. Throwing stones while hiding behind "moderator" doesn't garner you respect. Try to stay on subject and task!!!!!!!!!!

[kmacdonald]

Originally Posted by MartinR

I also thought so before, but actually, ESA managed to find these from space with the ESR satellite. And they are actually fairly frequent.

Sea buoys don't support that but they are very limited in location. That may be true in isolated locations but aren't reported buy merchant mariners on a regular basis. I'd like to know ESA's definition of rogue wave is.