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Old 16-09-2007, 17:59   #1
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Series Drogue

I have read an enormous amount of theories and practical accounts of storm tactics on catamarans and so much of the information is conflicting leaving the reader to decide for them selves what the best tactics are and which form of drogue / sea anchor is best suited for a given condition.
I have read a lot of conflicting advice on the use of sea anchors and I am now wondering if they are a worth while investment as the trend now appears to be towards the use of a stern series drogue for all severe weather conditions. From what I've read, the forces on a sea anchor / boat can be extreme while in the same conditions, the forces on a series drogue / boat are vastly less and there is also little chance of broaching or erratic swinging presenting a broad side to the weather.
There seems to be a problem convincing the boating community that running a series drogue from the stern is a much safer method in all conditions from strong wind to storm condition.
I am interested in your thoughts on the current theories and what methods our readers employ for them selves?
Do you think some of these theories are market driven ?
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Old 16-09-2007, 18:56   #2
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Not all storms are created equal, and what works in one storm may not work in another.

I carry both drogues and parachutes because they are designed to do different things. Each storm has a different character with a different sea state and different proximity to land, and so your strategy to deal with it will vary significantly in each situation.

I have used a parachute with good results, and I have trailed drogues with good results, and both situations were completely different.

I wouldn't go offshore without both of them on my catamaran, because I don't know what weather is going to happen when I am on passage.

I also carry immersion suits just in case the unthinkable happens. If Tony Bullimore can survive in a capsized monohull south of Australia in the cold southern ocean for five days using an immersion suit, then I am impressed with its capabilities.

Our recipe on Exit Only is an 18 foot Para-anchor International Parachute, a 120 cone series drogue, Gale Rider Drogue, and improvised drogues constructed with what we have on board, and added on top of all that is our immersion suits.

When I sail offshore, I'm not too worried about what's going to happen because we have done our homework, and we have lots of different things that we can do if problems arise with the weather.
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Old 16-09-2007, 19:15   #3
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Although Dave didn't mention it, on his website is a great little video on trailing warps. Worth the viewing.

Another device I think I'll pick up is this one: Seabrake

Jordan's site: series drogue, ocean survival also as some excellent information on it. As Dave said, it makes sense to me to have several possibilities on board, not only because of the different characteristics of storms and your proximity to land, but also because things happen and you may find yourself suddenly without one option. Redundant systems in such circumstances makes a lot of sense.

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Old 16-09-2007, 20:04   #4
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Originally Posted by Crak View Post
I have read an enormous amount of theories and practical accounts of storm tactics on catamarans and so much of the information is conflicting leaving the reader to decide for them selves what the best tactics are and which form of drogue / sea anchor is best suited for a given condition.
Me too................
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Old 18-09-2007, 02:04   #5
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I carry both drogues and parachutes because they are designed to do different things. Each storm has a different character with a different sea state and different proximity to land, and so your strategy to deal with it will vary significantly in each situation.
Right. But, even carrying both, there are still potential issues.

I understand, from reading other people's experiences, that:

1) In certain sea states, a parachute anchor imposes stresses that may be too severe, making a drogue more appropriate. And vice versa.

2) For a given storm (and we're talking big ones here), sea state within the first 36 hours may be significantly different from sea state later on (short versus long wavelengths, cross seas developing as a low moves and generates waves from new directions, etc.).


So, if a storm arrives and you initially put out a drogue because it suits the current sea state, you may want to change options when it develops into a different sea state.

However, I don't believe it's always easy to pull in the drogue, or sea anchor, mid way through a storm. So you may be either committed to the first option you chose, or you're committed to dump your (not inexpensive) equipment to try the other one. And then there's no going back to the original.

So that initial decision about which device is going to be best suited for the duration of a long storm may turn out to be a rather delicate one.

Martin
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Old 18-09-2007, 07:22   #6
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We laid to a parachute sea anchor in a storm north of New Zealand in a squash zone for nineteen hours with winds to fifty knots. When it came time to pull in the parachute we motored up to the chute and it took only fifteen minutes to retreive it.

We have parachute sea anchor chain plates in our bows that are through bolted to the decks with large bolts. Those chainplates are like mount Everest. They aren't going anywhere, and there's no problem with chafe. People who have chafe problems have not set up their system properly.

When we trailed drogues in the Atlantic ocean, we pulled them in by hand, but we could have used winches if we had needed to.

In our particular experience, we could have changed tactics without a problem with the storms that we were in.

That's not theoretical. That's the real world of an eleven year circumnavigation. We receive timely weather information on Exit Only, and if we are going to need a parachute, we don't wait till it's blowing a hundred miles and hour to put it out. On passage from New Zealand to Fiji or New Caledonia, I run the parachute bridle ahead of time and fasten it on deck if the weather is unsettled so that we can quickly and easily deploy the chute if needed.

If I was in a situation where I was lying to a chute that self destructed and was not possible to easily retreive, I would release the chute and then turn downwind to deploy the drogue from the stern. It would take about two minutes to release the chute and five minutes to deploy the drogue of choice.

When I go offshore in bad weather, I pull the chute, series drogue, and associated gear out of lockers before I head offshore, and I put them on the floor of our salon. I cover this gear with a few pillows and I sleep on top of them - they make a comfortable matress. In my video, warp speed you can see me asleep in the salon lying on the parachute, bridles, and drogues.

I my experience, deploying and retrieving emergency gear has been quick and easy because I have set my boat up to make it quick and easy.

Take a look at these chainplates that I put in my bow so that I can easily and safely use a parachute on my catamaran.



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Old 18-09-2007, 15:16   #7
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Originally Posted by maxingout View Post
we motored up to the chute and it took only fifteen minutes to retrieve it.


Those chainplates are like mount Everest. They aren't going anywhere, and there's no problem with chafe.

When we trailed drogues in the Atlantic ocean, we pulled them in by hand, but we could have used winches if we had needed to.

In our particular experience, we could have changed tactics without a problem with the storms that we were in.

That's not theoretical. That's the real world


I my experience, deploying and retrieving emergency gear has been quick and easy because I have set my boat up to make it quick and easy.
Thanks.
That helps a little.
It is hard for me as a novice to think I may know which to use when.
I always figured that the worst stuff should come at the bow since that is how boats are designed.
If one was to allow the bad stuff to come from astern then I am assuming the direction of drift is the one in which one wants the boat to go.
If one wants to go in another direction then a chute would be used to minimize drift.
It seems you are one that pre-plans for things and thinks ahead.
I often go through scenarios in my mind in the attempt to not be caught in a surprise but I have little offshore experience.
I guess one has to try to equip as best they can and then just get out there to try it.
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Old 18-09-2007, 16:30   #8
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Series drogues

Thanks for every one for replying to this thread as I am trying to encourage some healthy debate and personal views.
From what I read a parachute sea anchor attached to the bow can create enormous forces on the parachute, line and anchor point and that is why they some times break in severe weather. This is also true for drogues attached to the stern. Working loads should be calculated for all fittings and lines.
Most people think pointing the bow into severe weather is the safest option, but you are exposing the boat to the full force of every wave. Boats tend to swing on a parachute sea anchor exposing the boat beam on to the on-coming weather.
Trailing a drogue allows the waves to travel under the bridge deck while the boat is still slowly moving, reducing the energy inflicted on the hull.
Reading the research & development of the series drogue by Donald J. Jordan series drogue, ocean survival is very interesting and he suggests the day of the sea anchor is over, but I will leave that up to the reader.
For some time I was convinced a sea anchor on a multi hull was the best option, but I also believe in having multiple systems for different conditions, but the more I read about stern connected series drogues the more I am leaning towards this device as the best device to be deployed under most conditions. It also has the advantage of being able to vary the drag and to spread the load evenly across the whole system.
There are obviously times when a parachute deployed from the bow is convenient, such as standing off in deep water or minimizing drift to a lee shore, but if I am ever unfortunate to be caught out in a severe storm with plenty of sea room I think I would prefer to be hung off a stern connected series drogue.
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Old 18-09-2007, 19:28   #9
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Quote:
"Most people think pointing the bow into severe weather is the safest option, but you are exposing the boat to the full force of every wave. Boats tend to swing on a parachute sea anchor exposing the boat beam on to the on-coming weather."


Lying to a parachute does not "expose the boat to the full force of every wave" in our experience. We are in a catamaran floating on top of the water like a cork. Lying to a parachute is like riding on an elevator. Our boat rode up and down over the waves. It was an amazing experience because I thought it was going to be rough while lying to the sea anchor. It was totally opposite to my expectations. We didn't take any water on our deck as we rode up and over the waves. The motion was smooth and comfortable. We could have cooked a three course meal and eaten it in our salon if we wanted to because our boat was stopped dead in the water. It just slowly moved up and down with the waves.

With fifty knots of wind blowing across the decks, and bridles arms that were 20 feet apart, the boat pointed directly into the wind and seas. There was zero swinging on the bridle at those wind speeds. We were pinned like a wind vane with the bows pointing upwind into the seas.

After we deployed the chute, we wondered if the storm had somehow abated. The next day we talked to a container ship that had a seasick crew on board and they asked us what the heck we were doing out there in the storm. They had reduced their speed in the storm to a level that just gave them steerage to keep their bows into the seas. In the same storm, a ship dumped a bunch of containers into the sea - around 15 - if I recall correctly.

In our time on the chute we drifted something like half a mile by gps.

When we used a drogue in an Atlantic storm, we slowed the boat speed down to four and a half knots running downwind. It was much scarier using the drogue than the parachute because we were still moving and if the drogue lost its bite, we could accelerate into a broach situation.

If I am in a big storm, I want my boat to be stationary doing zero knots, riding up and down on the waves. I don't want the boat to be moving when I am hit by a wave. I want to go from zero to five knots rather than from four to twelve knots when I am hit by a wave.

For me the bottom line is this. Theoretical arguments are a trip to fantasy land. Each boat behaves differently in a storm, and all parachutes and all drogues are not created equal. Parachute failures happen with rotten and undersized chutes. Bridles chafe through when not properly tended or if there aren't parachute chainplates installed on the bows. Undersized and poorly constructed drogues can give drogues a bad name.

I know that drogues and parachutes work on my catamaran when used properly and deployed in a timely manner. But they must be in good condition and appropriately sized to the vessel size and design. One of the reason there is so much controversy and confusion is because people are comparing apples and oranges. Lying to a small cargo chute and to an 18 foot diameter Para-anchor international parachute are two completely different things. They aren't even in the same league. Similarly, warps, Gale Rider, and Jordan series drogues aren't in the same league.

The only way to get reliable information on drogues and chutes is to buy them and deploy them so that you know how they work on your yacht. The next best thing, is to talk to someone who has used them on their yacht, and find out what worked and what didn't work.

I've heard all the arguments, and that's all they are, arguments. Experience is what counts.
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Old 18-09-2007, 20:01   #10
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Bridles chafe through when not properly tended or if there aren't parachute chainplates installed on the bows.
Dave, thanks for the photos of your bow chain plates - very fine looking setup.

Just for education, may I ask how you attach the sea anchor rode and bridle to your pictured chain plates so as to minimize chafe (eg. does the rode pass through the hole in the vertical tab and then underneath the ring at the front; do you use knots or shackles; is there a pulley at the bridle end?)

Also, are you able to let out more rode, and adjust the bridle arm lengths, while the system is under load?

Martin
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Old 18-09-2007, 20:02   #11
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I'm sure I've read many of the same reports as others on this forum, and like most others have not experienced any of this in extremis. The little bit I would add is that my understanding of the criticisms of sea anchors has generally been of their use on mono-hulls which don't have a wide base for the bridle so do "sail" on the sea anchor, not sitting cleanly bow to the waves. The reports I've read suggest that this criticism does not typically apply to a catamaran, giving us the choice of both sea-anchors and drogues, whereas my reading (no real experience) suggests that drogues are a better option than sea anchors on mono-hulls.

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Old 18-09-2007, 20:26   #12
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The vertically oriented chainplate with an eye in it is a spinnaker chainplate for spinnaker blocks. So pay no attention to the chainplate with the drilled hole.

The parachute chainplates are the twenty five inch long chainplates that are through bolted to the deck, and there are twenty inch similar size stainless steel backing plates under the deck to which the deck chainplates are bolted.

Welded down each side of the chainplate is a bail that sticks out about five inches in front of the bow. The bails are about the diameter of a my finger. The bails are extremely strong, and when a 115 foot charter yacht hit my bow in the Caribbean, his bow struck the bail only bending the bail slightly, and doing no damage to the fiberglass on my bow at all. It turns out that the bails make excellent bumpers.

Each arm of my parachute sea anchor bridle is forty feet long, and at each end there is a large thimble to protect the one-inch three stand nylon bridle. I simply use a d-shackle to attach the bridle and thimble to the bail, and I have a chafe free solution to the bridle challenge. For us there was zero chafe when lying to the sea anchor.

We left New Zealand in the winter heading north, and we suspected that we were going to get hit north of New Zealand. We just didn't know how bad it was going to be. Because of that, we attached our bridle to the parachute chainplates before we left so that the were ready for immediate use. There would be no bending down on the bows to fiddle with d-shackles and seizing wire during a storm at sea. When we got three hundred miles north of New Zealand, we got into the squash zone and we simply went into our salon, pulled out the 500 foot tether, parachute, and float and attached it to the bridle that was already in place.

The parachute sea anchor chainplates with welded bail solved the chafe problem for us and makes it easy to deploy the chute when we know that bad weather is on the way.
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Old 18-09-2007, 20:32   #13
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One last comment about adjusting the bridle length and orientation. Using our set up, the only way we could adjust the bridle length or orientation would be to put a giant snatch block (which we carry on board) on one arm of the bridle and winch it toward the centreline of the boat. That gives us the option of making the bridle pull assymetrical to adjust for cross seas, but then it majorly puts the bridle at risk of chafe by the large snatch block.

We always had this option in the back of our mind, but we never needed to try it. I don't know if it would really work. But I do know that the Pardey's used a snatch block to adjust their parachute sea anchor bridle.
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Old 18-09-2007, 20:53   #14
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Dave, thanks for the detail.
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Old 19-09-2007, 04:00   #15
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Dave, thanks for the detail.
I too, thank Dave for sharing his extensive & valuable experience, and providing much practical information, upon which, we can all theorize solutions for our own situations.

Quote:
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... I my experience, deploying and retrieving emergency gear has been quick and easy because I have set my boat up to make it quick and easy ...
An excellent general rule - a corollary to which is: “Make it easy for the next guy, for YOU may be the next guy.”

I’ve found that, if it’s not easy, I may not do it (to my later regret).

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... Theoretical arguments are a trip to fantasy land ...
... I've heard all the arguments, and that's all they are, arguments. Experience is what counts.
Theory vs Experience:
Contrary to popular belief, a theory is not a ‘guess’, or ’speculation’. Neither is it meant to be ‘unrealistic’ or ‘impractical’.
A theory is an explanation of reality.
A well-developed formal theory is a statement that predicts the consequences of a particular action. It also states why such consequences occur. Thus if we were to create a theory template using only two sentences, we might come up with:
“If we do A, then B will happen.”
And:
“This is what’s happening now and here are the reasons why…”

Practical experience is not the opposite of theory. Rather, practical experience leads to the development of theories! When an individual encounters a certain phenomenon through first-hand, practical experience, that individual will tend to form a description of that phenomenon in his head so that he will be able to recognise that same phenomenon when it re-occurs. Repeated exposure to that phenomenon will lead that individual to differentiate between “editions” of that phenomenon which will eventually lead him or her to conclude that:
“If I do A, then B will happen because…”
Note the similarity to the theory template above.

While experience can be a great teacher, unfortunately the test comes ahead of the lesson.
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