Jordan Series Drogue vs Paratech Sea Anchor

[smackdaddy]

Now dude, if I was mouthing off - you'd know it. So what's changed in 25 years? Physics?

Okay, here's another study dated 2004, and it's from some dude in Oklahoma, so you KNOW it's legit:

http://www.scientificexploration.org...8_2_deming.pdf

Now, I have to admit, they weren't my roommates - and I didn't date their professors, but the McIver, May, and Monaghan Hypotheses (upon which I think you might be riffing) seem to be getting hammered by a lot of geeky white papers. So "facts" seem a bit nebulous here...but make great fodder for "Bermuda Triangle" theories.

That said, I'd be interested to see the papers that debunk the theories. Always up for a good read. Got links?

[mlibkind]

Be sure that you a comparing apples and apples. The series drogue must be weighted to work. This configuration is often compared to unweighted parachute type drogues. That's apples and oranges. Weight a parachute and it will not skip.

I also want to comment on sea anchor versus drogue. As others have said, they have different purposes. In the worse conditions I would want a sea anchor becuase it puts you head to wind or slightly off at an angle with a bridle. Either was you will ride well so long as you have adjusted the line length to minimize slack. The one thing you don't want to do is go beam to the waves.

The only really bad thing I can see with a sea anchor is that since you have no power and are not steering you have no control in the event of a rogue wave from a different direction.

A drogue is designed to slow you down when heading downwind. You still need to steer. What you want is a device that supplies enough drag to prevent broaching. There is, IMO, no reason to have a drogue that severely decreases your speed because if that is what you want to do then you should use a sea anchor. I would use the drogue to stablize the boat on the face of waves (no broach) but still want to move downwind at some reasonable speed.

I had heard, and a Good Old Boat article says, "A properly sized series drogue will keep the boat speed down to 1 to 1 ½ knots in storm conditions, so it does not require the crew to steer." Therefore a series drogue is designed much like a sea anchor; it severely reduces the boat speed. If that is what you want, then I'd go for a sea anchor so that I don't have my stern to the waves.

But there is a much more important factor that few people think about when dealing with a storm. That is, if you are still moving and it is important what direction you are moving in. You don't want to be moving in the same direction as the bad weather ... in that case you are just going to spend more time in the bad weather if you do that.

If you can't sail in the direction opposite to which the storm is moving, then you probably want to be stopped (use sea anchor) as opposed to using a drogue and moving with the storm. Knowing which way the storm is moving is the key. More often than not it is not in the direction of the wind.

There is no simple solution.

Originally Posted by SaltyMonkey

The series drogue is NOT a sea anchor from the stern and you DO need to have the ability to steer the boat in order to keep stern into waves. The advantage of a series over a regular drogue is that it is less likely to ride and skip from astern under force, and that the forces are more evenly distributed.

When using a drogue from astern you want to keep the boat moving - not too fast and not too slow. The decision then begins on which drogue is best for your design.

For an introduction to storm management and testing of devices, read Adlard Coles "Heavy Weather Sailing"

[mlibkind]

While a series drogue is not an anchor, it reduces the speed of a boat much more than a parachute type drogue. The series drogue may not be your best choice if your main reason for using it is to provide better control downwind while still making progress.

[sabray]

Very good read on a deployed sees drogue. Ming Ming ant art....... Sailing. Explains in reL situation how effective and you can imagine why.Uris superior as a drogue transferring shockloads, holding onto a further wave cycle transferring energy. Ideally attached with 2 chain plates port and stbd stern. Reduce any opportunity for chafe. It's amazing how lline being chafed can get chewed up under high load.

[mlibkind]

Sabray, please give more info on how to find this article.

Originally Posted by sabray

Very good read on a deployed sees drogue. Ming Ming ant art....... Sailing. Explains in reL situation how effective and you can imagine why.Uris superior as a drogue transferring shockloads, holding onto a further wave cycle transferring energy. Ideally attached with 2 chain plates port and stbd stern. Reduce any opportunity for chafe. It's amazing how lline being chafed can get chewed up under high load.

[ice]

Originally Posted by mlibkind

Weight a parachute (type drogue) and it will not skip.

This is not correct. We have had a weighted single element drogue 'skip'. In large steep waves, it will pull out of the face of the waves and skip.

The only really bad thing I can see with a sea anchor is that since you have no power and are not steering you have no control in the event of a rogue wave from a different direction.

Sea anchors (over the bow) are much less comfortable (than running with a drogue), with the boat tacking back and forth. The loads on the rode are much higher, leading to a much higher incident of failure (of rode or attachment hardware). And the loads on the rudder are higher (As the boat can surge backwards in a wave strike) leading to a higher incident of rudder damage.

A drogue is designed to slow you down when heading downwind. You still need to steer.

That depends on the specific boat, but you are generally incorrect. Generally boats have enough windage forward (roller furled jib) that they will naturally run/track downwind with a drogue out. This has been well proven, even when boats have lost their rudders they can run downwind with a drogue out. And in any case, any steering necessary can be done with an autopilot or wind vane. We have run with a drogue that way many many times.

There is, IMO, no reason to have a drogue that severely decreases your speed because if that is what you want to do then you should use a sea anchor.

I mention three reasons above: comfortable, loads/failure, rudder damage.

You don't want to be moving in the same direction as the bad weather ... in that case you are just going to spend more time in the bad weather if you do that.

In most cases it is extremely effective to be moving away from the worst waves. You would definitely NOT want to be sitting still in the gulf stream when by running 50nm you can get out of the larger current driven waves. You would not want to be sitting still in the track of a compact low when by running 50nm you can get out of the storm force wind area and only into gale winds.

If you can't sail in the direction opposite to which the storm is moving, then you probably want to be stopped (use sea anchor)

Incorrect. Typically you would want to move 70-90 degrees to a lows track in order to maximize separation. If you are directly in front or in the 'navigable semi-circle' (the polar side of the low) then you will have (usually) wind direction favorable to running away from the low. If you are in the 'dangerous semi-circle' (the equator side of the low) then the wind will be forward and progress is harder.

.....

[sabray]

Originally Posted by mlibkind

Sabray, please give more info on how to find this article.

Mingming & the Art of Minimal Ocean Sailing (Paperback)
Roger D. Taylor
He also has a very good web site. Not about the drogue but sailing a small boat he sets the drogue. Looses the drogue due to chafe. The story is a good read. Also available as a e book.

[xxuxx]

Also IMHO it matters as to how bad the waves are breaking. This would contribute to determining which to use. When it is so bad that all you want to do is crawl into your bunk and pray, its time for the sea anchor. If the winds are blasting you and your vessel at speeds much over 12 knots with mildly breaking seas, I use the drogue. For what it is worth from real experience.

[Bulawayo]

Originally Posted by colemj

I really shouldn't be in this discussion because I have no experience with these devices. But I have talked to a few people who have deployed a JSD (running before a storm bare poles) and they said they maintained 3-4kt of boat speed with the drogue. All said their autopilot handled it perfectly and the boat settled down nicely. They also said that they would see large following seas come up behind until they reached the drogue and split and go right around their boat, leaving them riding in a calm "slick".

Again, heresay - I don't have any personal experience. Maybe someone who has deployed one can comment?

Mark

Mark, we have used JSD's for several years and am very happy with our experiences. They are not easy to retrieve - we normally are content to leave it in the water until the weather has moderated to 3 knots and even then it takes around two hours to recover. As long as we have sea room (and always have had, so far) we prefer to adjust our course if necessary.
I have to laugh when I read the comments about preparing adequately by removing our furling gear........ that speaks volumes.

[Don C L]

OK I know this is an old thread but I thought I'd drop this in where folks searching could find it. Many of you may have seen this site but I thought it was really a good resource for those who haven't seen it: "Victor Shane's Drag Device Database"
Victor Shane's Drag Device Data Base | Using Parachutes, Sea Anchors and Drogues to Cope with Heavy Weather – Over 130 Documented Case Histories