Drogues or sea anchor or neither

[Snowpetrel]

https://youtu.be/bOEWo4x_N44

An oldie but some useful stuff. Skip to about 6:30 to see why seabrake added the holes. I have one of the old plastic ones. Good bit of kit.

[Fi2010]

Originally Posted by thinwater

Your notion that allowing flow through the drogue by adding holes is incorrect, as Fiorentino stated. This has been tested by MANY people. There are reasons to increase porosity or provide vents, but increasing drag is not one of them. Second, the Shark has 4 rather large vents. Would the drogue inflate correctly with these holes? Probably not, depending on the number, size, and location, but I do not know and am not interested in testing it.

I think the thing you are missing is that a solid drogue (or one with perimeter vents) creates a large wake around it, as the water goes around it, increasing its effective size. A porous drogue creates a smaller wake because much of the water goes through it instead of around it.

Finally, we know that the Galerider has much LOWER drag than more solid drogues of the same diameter. Very high porosity.

But you can ask Fiorentino or try your experiment. The same experiment would apply to the Delta Drogue.

To add to your comment.

Why would any one of you want to modify the Shark Drogue or any other drogue? For one, why modify something that works? Two, wouldn’t this nullify any warranty a manufacturer offers? Three, the slots/vents built into every single speed-limiting drogue are technically holes. Adding more holes have no value in this circumstance.

[Fi2010]

Originally Posted by rabbi

Thank you!

Unfortunately that means Fio will not provide answers to my questions.
These answers are obvious so i will answer myself.

Q1: not interested in fair comparison and too lazy / ignorant to fake the data appropriately
Q2: not interested in fair comparison and too lazy / ignorant to do things right
Q3: if a drogue fails when i need it most its a Bad thing.

You continue to single out one company with negative claims like lazy, ignorant, fake data, bias, dishonest… the list goes on. You spend 20 posts trying to prove your accusations.

When a question is answered you respond with more negative comments. When an option is provided on how to make a storm drogue perform better you claim the data is incorrect and will not work in heavy weather.

Can you please share your credentials? You’re making some pretty bold claims without any supporting evidence.

[rabbi]

Originally Posted by Fi2010

You continue to single out one company with negative claims like lazy, ignorant, fake data, bias, dishonest… the list goes on. You spend 20 posts trying to prove your accusations.

When a question is answered you respond with more negative comments. When an option is provided on how to make a storm drogue perform better you claim the data is incorrect and will not work in heavy weather.

Can you please share your credentials? You’re making some pretty bold claims without any supporting evidence.

Why? I gave the reasons in post #73 and post #78.


You keep posting tons of "tech reports" and promotional videos to support the impression that you have done intensive scientific research. Enough to cause the mods to delete most as it was considered "extensive advertising".

All just smoke and mirrors - at the same time you fail to provide simple and precise answers to three simple but criticizing questions.


In case you have forgotten the questions Q1-Q3 please re-read post #141.

Q1: You admit that the drogues were not sized correctly for the test boat that is mentioned in the report. Instead the the drogues were sized for some imaginary boat that is not mentioned anywhere in the test report.

Q2: No answer

Q3: You haven't answered the question but just say its not an issue.



Finally: I can't share my credentials - I am just a stupid cruiser without any credentials who has the feeling that there are a few holes in your promotional "research" papers - and guessing from the other posts in this thread I'm not the only one.
And I'm asking a few questions that you don't seem to like. And since you did not care to answer them I decided to answer them myself.




Somehow I can't get the song "never wrong" by Disturbed out of my mind...

[Fi2010]

From our understanding, if someone makes an inaccurate claim we can respond with supporting evidence, including links. We now understand only an individual can provide links. Service providers can not. Still not sure if we can edit, copy, paste some of our data and place in a post to address inaccurate or misleading comments.

Something to consider is attending boat shows. Lots of blue water sailors and industry experts to talk to. Boat shows frequently support seminars making it easy to learn more. What’s even better is you can check out the equipment for yourself. Nothing beats touching and examining the very items you’re considering storing on your boat.

Another source is YouTube. All kinds of para-anchor and storm drogue videos available from many sources.

[Jim Cate]

Nothing beats touching and examining the very items you’re considering storing on your boat.

Well, I personally think that field testing those items beats the hell out of "touching and examining"them at a show.

And I too am beginning to wonder why you will not even attempt to answer Rabbi's specific queries. Sidestepping them isn't doing your position any favors.

Jim

[Uncle Bob]

Originally Posted by Fi2010

From our understanding, if someone makes an inaccurate claim we can respond with supporting evidence, including links. We now understand only an individual can provide links. Service providers can not. Still not sure if we can edit, copy, paste some of our data and place in a post to address inaccurate or misleading comments.

Something to consider is attending boat shows. Lots of blue water sailors and industry experts to talk to. Boat shows frequently support seminars making it easy to learn more. What’s even better is you can check out the equipment for yourself. Nothing beats touching and examining the very items you’re considering storing on your boat.

Another source is YouTube. All kinds of para-anchor and storm drogue videos available from many sources.

Mate, all you have to do is answer the questions asked, specifically, short and succinct answers.

[Fi2010]

Rabbi,

For over two weeks you’ve attacked our research efforts. Can we try something a little more simple?

Would you be willing to conduct sea trials with us? We’re happy to deploy the equipment to your specifications. All we ask for in return is the same courtesy. We’ll even pay for the event. Does this sound fair?

[rabbi]

Originally Posted by Fi2010

Rabbi,

For over two weeks you’ve attacked our research efforts. Can we try something a little more simple?

Would you be willing to conduct sea trials with us? We’re happy to deploy the equipment to your specifications. All we ask for in return is the same courtesy. We’ll even pay for the event. Does this sound fair?

I know you'll use this against me but: No. I am not interested.

There is no point in doing it to my specifications. I am no scientist and no researcher, and I am not in the drogue business. My specific knowledge of drogues is limited, but there is no need to know much about drogues to find evidence of sloppy or biased tests.
I know we won't get along well personally. Not the sort of company I'd like to have for a trip in really nasty weather (which is required for Q3).

So I don't consider this fun. Why should I spend a couple of days and fly halfway across the globe to do something that I don't enjoy?
To proof I can do better than you? I'd surely make my own mistakes! Two fools don't make a scientist.
Money? If you pay me enough to convince me to do something I dislike I would be considered compromised. I would end up in the same boat as you (where I don't want to be).

Nope. You just have to deal with these questions. Or ignore me until I get too bored to pester you.


BTW: once again no answer

[thinwater]

Something I've never seen tested, either in controlled conditions or in the field, is a single element drogue of equivalent drag to a JSD. Let me explain.

A JDS creates a lot of drag, about 2-4 times more than a conventionally sized slowing drogue. This was the designers intention, because his devise was meant to save people from survival storms, not serve as a steering aid or make the boat more comfortable in blustery conditions. In fact, that is one of the best uses of conventional drogues; making the boat more manageable and comfortable when it is really rough but not scary. I think a lot of people on this thread overlooked that. This is something a JSD is not good for. Most tools do one job best.

Single element drogues are vulnerable to surfacing because the extreme load pulls them to the surface, and the only thing really holding them down is the wake that builds up over the drogue (which is a quite a lot at higher speeds). But this vulnerability is related to speed, because load/area is related to speed. And we are testing single element drogues at higher speeds and higher loadings that the JSD. In fact, I did some testing of shortened JSDs as a possible steering drogue, at higher speeds, and it was unstable and WORSE than the better conventional drogues. So much for the JSD design being magic. Shorten one about 4 times, tow it at 7 knots at short scope and see what I mean. It just skims and does so in an irregular pattern. It also beats the cones to death.

So what happens if you use a single element drogue that has 4 times more area (twice the size) than is typically recommended? Instead of a 2' diameter drogue, use a 4' diameter drogue. The boat will slow to 2-3 knots. The drogue will run deeper, not very close to the surface. I did this is slow speed tests, and at 2-3 knots, the drogues are not pushing big wakes near the surface. They are loafing. But I did not test this in big waves (those tests where always at higher speeds).

The point is that comparing a Shark (or Delta Drogue or Seabrake or Gale Rider) to a JSD using recommended sizing is not comparing apples to apples. Whether right or wrong, it is different.

I don't know how this would be in a storm. I'm guessing a little more harsh, but perhaps not more harsh than a JSD with a Dyneema rode. There may be problems with slack in certain wind/wave combinations. One advantage of small drogues is that forward motion is more able to keep the slack out. But I don't know. Obviously big chutes are used as sea anchors and this is part of that continuum.

And then there is the whole issue of getting pooped. My last boat could tolerate that, my new one could not. I'll leave that alone.

[rabbi]

Fully agree.

The JSD is only good for very slow controlled drift dead downwind, and not for steering or just reducing excessive speed.

Cone fraying is a real concern for the JSD. All accounts I have seen mention the fraying only for the first few meters of the JSD. Over time the first cones get frayed, and the following cones come into play. That of course reduces maximum breaking force. At least its not a sudden failure but just the drogue getting weaker over time. Oversizing the JSD (more cones) helps to some degree. But still not perfect.


A single drogue on the other hand may be good for steering and more stability, but IMO only in moderate conditions. Once overloaded the risk of pulling it out of the face of a wave is real.
The idea of controlling the scope so that the drogue is always on the back of the next wave somehow doesn't work in my world - the waves just don't cooperate. In nasty weather they just don't come in the exact uniform pattern required for this to work.
So any single element drogue can fail in really bad conditions.



As mentioned before I think one way of handling this would be by chaining a few conventional drogues into series.
Production and quality control is easier for a handful of elements than it is for hundreds, so problems like fraying should be easier to address.
The risk of pulling most or all drogue elements out of the water should be nil if three or more elements are used and spread over say 100m.
There is in my view no need for stretch in the lines between the elements, as the waterflow will absorb most of the shock loads, so dyneema should do.


Maybe I'm completely wrong but that would be my attempt at building a drogue: Three daisy chained elements connected by dyneema.
A three element drogue should be much easier to deploy, retrieve and stow than a JSD - and at the same time almost as powerful and dependable.
It wouln't offer the dynamic breaking power adjustment (more speed => more cones active => bungee like feeling) that the JSD has but I have no idea if this would really be a problem.


I like the shark as it's design holds a lot of water (further reducing the risk of pulling it out of the water), seems designed for daisy chaining and it's a neat package.
However pricing makes a three element shark drogue very hard to swallow. Not to mention that I don't want to give business to folks like Fio.


BTW: Still no answer

[Jim Cate]

IIRC, Evans Starzinger reported using two single point drogues (unknown design) in series on a very long warp when in difficult conditions in the southern ocean. From memory, the warp was ~200 meters with one drogue at the mid point, one at the end.

He also had used a single unit at t he end of the 200 m warp with some success, reporting that at 100 m distance it would pull out of the wave fronts.

Sure sorry he isn't around to join in this discussion...

Jim

[a64pilot]

I’m under the impression that a JSD is more similar to a Sea anchor than a Drogue?
I have a Sea anchor, and a gale rider drogue. My plan is the drogue is for emergency steering and to be towed from the stern in bad, not survival conditions.
My plan for survival conditions is the sea anchor, off of the bow.

I can understand why a Cat wouldn’t want to deploy a sea anchor off of the bow, but it’s my belief due to my excessive aft windage, that is my best plan, cause I can’t jettison my Solar panels in a storm, I don’t think.


So I guess what I’m asking, is why the comparisons of a JSD to say gale rider device, aren’t they meant for different things?

[thinwater]

Originally Posted by Jim Cate

IIRC, Evans Starzinger reported using two single point drogues (unknown design) in series on a very long warp when in difficult conditions in the southern ocean. From memory, the warp was ~200 meters with one drogue at the mid point, one at the end.

He also had used a single unit at t he end of the 200 m warp with some success, reporting that at 100 m distance it would pull out of the wave fronts.

Sure sorry he isn't around to join in this discussion...

Jim

The first drogue was a Delta Drogue. He reinforced the center and added a grommet so that the secondary rode could pass through. I believe he had a Dyneema section in there to prevent chafe. I have a photo but not where I can easily post it.

The second drogue may have been a Gale Rider, but I'm not certain.

The Seabrake and Gale Rider have provisions for a rode to pass through without modification.

The JSD is about 1/2 way between a sea anchor and speed limiting drogue in braking force. It is quite different from both, in a separate class.


In fact, a sea anchor works better on cats than it does on monohulls because they are light and can use a wide bridle. At least that is the conventional wisdom.

[a64pilot]

Not trying to start any kind of bashing, but I can see how that a lightweight Cat in stupid high winds, coming off of a wave with the bow high, could lift out of the water, whereas from the stern it would seem to be much less likely.