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Old 07-06-2016, 07:01   #61
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Re: Use of drogue/parachute anchor on Catamaran

Tandem drogues are an interesting topic. Starzinger wrote somewhere that he has done this with good success (A Delta drogue with something else trailing), and one of the earlier posters said they were set up for this. I took the hint and did both small scale testing (easier and safer to simulate really bad conditions by overloading smaller drogues in 30-40 knots over a bar) and full scale testing. While placing 2 ground anchors in a row is nearly always bad (the intermediate rode tension does bad things to them), the oposit seems to be true of tandem drogues. The fact that JDS is so robust suggests this is true.

  • The closer drogue will come out of waves, but it will not be thrown forward; the secondary holds it back and down, pulling it back into the meat of the wave within 1-3 seconds.
  • The contracting rode will not rubber band the drogue forward when it pulls out. When a drogue pulls out of a wave, the rode looses tension and shrinks, easily 10-20 feet, allowing the drogue to fly forward with the breaker. The second drogue prevents this.
  • Unless the spacing is very poor, they will never be out at the same time.
  • The secondary will run deeper (it has ~ 1/2 the rode tension).
  • Drag forces are MUCH more steady; instead of 30-50% variability, only 10-15% variation (not including affects of waves hitting the boat). At least in part, this is because the waves move over them at different times. Less pulsation and chafe on the rode and bridle.
  • Drogues are smaller and thus easier to handle. Important once the boat reaches about 45 feet.
  • Drag is adjustable; let out one, then let out the other. Same with recover; you can winch this in with a light storm load on it, but I bet that's impossible with a JSD.
  • I liked the Galerider as the trailer and the Seabrake closer; the Seabrake generates a lot of force and is easy to recover, and the Galerider is so smooth. But I tried this with 5 brands in many combinations and the differences were pretty minor. The big factors were rode length, intermediate rode length, and bridle adjustment. As Starzinger said, any calculations based on wavelength are fuzzy at best; the "answer" often varied in minutes as we passed over bars and WL changed. The right answer generally seemed to be "enough."
A little more complication, but based on my limited experience, it is the direction I would lean. But we will only learn the important stuff if folks rig for it and try it.


My only other observation is that you need to test your theories in rough but not desperate weather. A lot of the stuff in books is wrong, or at least wrong for your boat. I'm guessing some of the authors never actually tried it themselves.
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Old 07-06-2016, 07:19   #62
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Re: Use of drogue/parachute anchor on Catamaran

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Originally Posted by thinwater View Post
Tandem drogues are an interesting topic. Starzinger wrote somewhere that he has done this with good success (A Delta drogue with something else trailing), and one of the earlier posters said they were set up for this. I took the hint and did both small scale testing (easier and safer to simulate really bad conditions by overloading smaller drogues in 30-40 knots over a bar) and full scale testing. While placing 2 ground anchors in a row is nearly always bad (the intermediate rode tension does bad things to them), the oposit seems to be true of tandem drogues. The fact that JDS is so robust suggests this is true.

  • The closer drogue will come out of waves, but it will not be thrown forward; the secondary holds it back and down, pulling it back into the meat of the wave within 1-3 seconds.
  • The contracting rode will not rubber band the drogue forward when it pulls out. When a drogue pulls out of a wave, the rode looses tension and shrinks, easily 10-20 feet, allowing the drogue to fly forward with the breaker. The second drogue prevents this.
  • Unless the spacing is very poor, they will never be out at the same time.
  • The secondary will run deeper (it has ~ 1/2 the rode tension).
  • Drag forces are MUCH more steady; instead of 30-50% variability, only 10-15% variation (not including affects of waves hitting the boat). At least in part, this is because the waves move over them at different times. Less pulsation and chafe on the rode and bridle.
  • Drogues are smaller and thus easier to handle. Important once the boat reaches about 45 feet.
  • Drag is adjustable; let out one, then let out the other. Same with recover; you can winch this in with a light storm load on it, but I bet that's impossible with a JSD.
  • I liked the Galerider as the trailer and the Seabrake closer; the Seabrake generates a lot of force and is easy to recover, and the Galerider is so smooth. But I tried this with 5 brands in many combinations and the differences were pretty minor. The big factors were rode length, intermediate rode length, and bridle adjustment. As Starzinger said, any calculations based on wavelength are fuzzy at best; the "answer" often varied in minutes as we passed over bars and WL changed. The right answer generally seemed to be "enough."
A little more complication, but based on my limited experience, it is the direction I would lean. But we will only learn the important stuff if folks rig for it and try it.


My only other observation is that you need to test your theories in rough but not desperate weather. A lot of the stuff in books is wrong, or at least wrong for your boat. I'm guessing some of the authors never actually tried it themselves.

Using two JSD's that can be connected may make this a quite useful idea. An issue would be that you'd have to know in advance whether to set one or two. But this could be alleviated by having the second JSD also set up as a complete secondary drogue. Then, pull the bridle of the first one over to one hull and lay the second off the other hull. Obviously, not so great for monos.
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Old 07-06-2016, 07:27   #63
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Re: Use of drogue/parachute anchor on Catamaran

Having not analysed the Database or JSD sites yet how difficult is it to retreive JSDs in storm conditions or conditions that are still challenging?
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Old 07-06-2016, 07:41   #64
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Re: Use of drogue/parachute anchor on Catamaran

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Tandem drogues are an interesting topic. Starzinger wrote somewhere that he has done this with good success (A Delta drogue with something else trailing)
Yea, we used a delta drogue (which I modified by adding a dyneema strop thru its middle to carry the load to the second drogue) and a galerider. We would put the galerider out on 300' of rode, and then if we ever felt we needed more hook the delta on with another 300'. We used 300' for no real scientific reason - just because our spare anchor rodes and shore lines were that length.

It seemed like a good solution, and I can not see any big downside to it, but I moved to it quite late in our cruising and we really only tested it in gale conditions and did not have anything really severe.

Regarding para anchors . . . . We were big drogue fans and users, but I was always very aware they needed running sea room. We also carried a para in case we were ever pinned too close to an iron bound coast (or too close to a nasty sea spot/area like a major ocean current axis flowing against the wind) to have safe room for the drogue.
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Old 07-06-2016, 16:59   #65
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Re: Use of drogue/parachute anchor on Catamaran

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Originally Posted by SVNeko View Post
Using two JSD's that can be connected may make this a quite useful idea. An issue would be that you'd have to know in advance whether to set one or two. But this could be alleviated by having the second JSD also set up as a complete secondary drogue. Then, pull the bridle of the first one over to one hull and lay the second off the other hull. Obviously, not so great for monos.
JSDs are already flexible with regards to breaking force. They use the catenary caused by the weigth at the end to achieve a relatively stable boat speed.
See figures 5 +6 here .

Slow boat means more catenary, which means more cones in a vertical position and less breaking force. Fast boat means less catenary, more active cones and more breaking force.

If you use a JSD with too little weight at the end it does not have much elasticity, because it is strechted in full and all cones are active.
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Old 07-06-2016, 17:07   #66
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Re: Use of drogue/parachute anchor on Catamaran

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Yea, we used a delta drogue (which I modified by adding a dyneema strop thru its middle to carry the load to the second drogue) and a galerider. We would put the galerider out on 300' of rode, and then if we ever felt we needed more hook the delta on with another 300'. We used 300' for no real scientific reason - just because our spare anchor rodes and shore lines were that length.

It seemed like a good solution, and I can not see any big downside to it, but I moved to it quite late in our cruising and we really only tested it in gale conditions and did not have anything really severe.

Regarding para anchors . . . . We were big drogue fans and users, but I was always very aware they needed running sea room. We also carried a para in case we were ever pinned too close to an iron bound coast (or too close to a nasty sea spot/area like a major ocean current axis flowing against the wind) to have safe room for the drogue.
I always thought that something between the extemes would be most useful.
A one-device drogue has the same issues as a sea anchor (flying, tumbling) so I don't buy into these.
A 130+ cone JSD is IMO much safer but expensive, labor intensive, bulky to store, somewhat complex to deploy and not easy to retrieve as these cones don't run through small winches easily.

Maybe a drogue consisting of 3-5 larger drag devices is the solution? does not tumble or get airborne like a sea anchor. But also easier to store, deploy and retrieve than a JSD.

The problem is: how many devices, which ones and how big for a certain boat?
Jordan provided a guideline that one can adhere to, this is missing for other alternatives.
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Old 07-06-2016, 17:23   #67
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Re: Use of drogue/parachute anchor on Catamaran

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The problem with this line of reasoning is that it is exceptionally difficult to engineer. The bridle is subject to chafe and both polyester and nylon are subject to fatigue more rapidly than metal (in general). So to make certain the line would fail first means it will very likely fail from fatigue or chafe. Estimating the strength of the layup is probably beyond everyone on this thread (if you are a mechanical engineer or equivalent, you have my sincere apology). It is complicated and is a skill set we don't have... and there are many certainly skills engineers don't have. The my practical answer (I am an engineer) is to be certain that the hull is stronger than the fasteners (in this case cleat bolts in shear/tension). There is NO reason to assume that chain plates will pull a chunk out of the hull. However, I personally feel that effort is better spent making certain that the cleats are up to the job, since they offer far more versatility.
Thinwater, of course you are correct. The point the boat deisgner was making to me was that we do not have to go overboard (no pun intended). We all like substantial cleats/strong points/chainplates - its a question of what is reasonable. Take a close look at your mast chainplates and you might be suprised at the arrangement. The SWL of lines is well documented and my drogue was constructed by Ace Sails and has been used in fairly severe conditions without too extreme reinforcement being necessary.

I used to do 4x4 driving in the desert in Botswana. We would occassionaly see a driver bogged to the floor pan as his vehicle was so overloaded with rescue equipment whilst a lightly loaded vehicle would simply drive passed.
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Old 07-06-2016, 18:05   #68
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Re: Use of drogue/parachute anchor on Catamaran

For what it's worth, I would never deploy a para anchor off the bow. I carried a 12 footer through the Pacific and it was rigged as a bridle, per Larry Pardey's advice. Effectively, this allows you to heave to in a hurricane with the boat quite happy. Deployed from the bow, you spend all night on a trampoline. Just my opinion.

When we take our current boat south, we'll carry a Sea Brake to tow off the stern. If you can slow the boat down in a real blow and head more or less straight downwind you can survive most anything. A para anchor would have to be bigger than I want to handle for Delfin, but from conversation with people who have deployed a proper drogue off the stern I am pretty sure I will have a reasonable strategy for surviving the unexpected. Not a real fan of the Jordan drogue as they need to be really, really long to be effective. For Delfin, Lord knows how long but a big Sea Brake should accomplish pretty much the same and be easier to handle.

YMMV.
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Old 07-06-2016, 18:25   #69
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Re: Use of drogue/parachute anchor on Catamaran

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Originally Posted by SVNeko View Post
Using two JSD's that can be connected may make this a quite useful idea. An issue would be that you'd have to know in advance whether to set one or two. But this could be alleviated by having the second JSD also set up as a complete secondary drogue. Then, pull the bridle of the first one over to one hull and lay the second off the other hull. Obviously, not so great for monos.
The 2 string idea is interesting, but I'd be (perhaps pointlessly) worried about the 2 tangling. There is a lot of yawing in big waves. It is also a lot of rope since they need to be quite far back.

No, you do not need to decide in advance, though it does help to make some preparations if you are using bridles. You do need to deploy the second while the loads are still manageable.
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Old 07-06-2016, 18:35   #70
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Re: Use of drogue/parachute anchor on Catamaran

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.... For Delfin, Lord knows how long but a big Sea Brake should accomplish pretty much the same and be easier to handle.

YMMV.
There are 2 problems with a single drogue, in my experience:
  • If the boat is big (Delfin) the drogue will be hard to recover filled with water; Seabrake is not bad, but Delta is a bugger when full and I know my back could not handle the one you need! A Galerider would need to be quite large to give good braking force, but they are super easy to handle.
  • A single drogue can (will) always pull out of steep waves faces. Sort of like being anchored on too short scope. This becomes worse and conditions become worse.
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Old 07-06-2016, 22:06   #71
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Re: Use of drogue/parachute anchor on Catamaran

I don't know about 2 drogues off the stern. It just seems so complicated when a very simple and elegant solution lies in the Jordan Series Drogue.
I have been in conditions twice where the JSD saved my bacon. Incidentally, in both situations 7 boats went down or were abandoned each time.
The the last hurricane the skipper died.

I have been there and done that and I would never leave port without my JSD. PERIOD!
A recommended attachment comes with the drogue. It is also on Ace Sailmakers website. I think it is over engineered and difficult to attach the drogue to in big seas.
When I had Kimberlite built I had the factory’s architect design underpinnings specifically for the drogue.
So far so good.

I do recall a funny situation while on the drogue. In my Tartan 37, we were about 300 miles north of St Thomas on our way back to NY. Herb Hilgenberg said to stay put as we were going to face 50-60 knots and on the north side of the storm it was blowing full hurricane conditions. Therefore, we put out the drogue and spent the night riding down wind. No waves broke onboard. The wind got down to 40 knots in the morning and the boat started rolling from beam to beam- very uncomfortable. I called Dave at Ace sailmakers and described the situation. He did not know why my boat was doing this. He gave me Mr. Jordan’s phone number and I called him. I explained the situation and he said-"I know what the problem is"--- “Not enough wind" Kind of funny. We pulled in the drogue and sailed through 2 more gales on the way to Bermuda. When we arrived the other boats looked like the walking wounded, di-masted, smashed lifelines, solar panels, and shredded sails. On a friend’s 80 footer a wave tore off 3 inch diameter Davits.

We had no damage
Case Closed
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Old 07-06-2016, 22:58   #72
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Re: Use of drogue/parachute anchor on Catamaran

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Hello friends,

1. What is the difference between a drogue and a parachute?
First begin with the difference between a drogue and a sea anchor. A lot of people think that they are interchangeable terms. I even had a licensed marine surveyor who thought they were the same thing. A sea anchor is deployed from the bow, just like your primary anchor. A drogue "drags" from the stern.

The word parachute should not be mixed in with a discussion of drogues and sea anchors. Some drogues look like parachutes, but not all of them do. I'm not aware of any sea anchors that look like anything except parachutes, so maybe sea anchor and parachute are close to synonymous, but that still confuses the purpose of the device with the shape of it.
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Old 08-06-2016, 06:09   #73
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Re: Use of drogue/parachute anchor on Catamaran

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First begin with the difference between a drogue and a sea anchor. A lot of people think that they are interchangeable terms. I even had a licensed marine surveyor who thought they were the same thing. A sea anchor is deployed from the bow, just like your primary anchor. A drogue "drags" from the stern.

The word parachute should not be mixed in with a discussion of drogues and sea anchors. Some drogues look like parachutes, but not all of them do. I'm not aware of any sea anchors that look like anything except parachutes, so maybe sea anchor and parachute are close to synonymous, but that still confuses the purpose of the device with the shape of it.
There are (just to confuse things) drogues that look like parachutes. They function about like other drogues.
Para drogues - Para Anchors
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Old 08-06-2016, 07:29   #74
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Re: Use of drogue/parachute anchor on Catamaran

I'm thinking of going with the Fiorentino Shark Drogue. Anybody have experience with it?


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Old 08-06-2016, 07:52   #75
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Re: Use of drogue/parachute anchor on Catamaran

I was fortunate that I have a hydraulic leg on my motor, At night I would lower the drive leg into the water and have about a foot of the bottom of the Genoa open,
That kept me in a straight line and running straight down the waves,
In very heavy seas it was the same, Lower the leg and a very small bit of the Genoa open, How much, Depended on the waves, I could regulate the speed with the Genoa,

I did have a drogue on board, But being single handed, I was reluctant to use it,
And the Drive leg worked very well, Even in the biggest waves I encountered,

Always had a following sea and wind when I used it, Or asleep at night,
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