Series Drogue on a Production Boat ?

[nv5l]

Originally Posted by rtbates

Hey Dave you wrote: a stern drag device aims to prevent this by aiding the rudder, firstly by slowing the boat somewhat so that the rudder is not over whelmed , and secondly by providing a correcting force on the stern to aid in keeping the stern aligned to the drogue and hence the wave.

Is the result of this not having the boat held back allowing the wave to pass under? Is that not the whole idea, keeping the boat OFF the wave face?

His description, while consistent with conventional drag devices, doesn't apply to the JSD.

The video link I posted, as well as plenty of others, clearly shows the wave safely passing under the boat. As the boat begins to accelerate, the JSD applies more and more drag to slow her down and keep her under control. The rudder plays little or no part.

[goboatingnow]

Originally Posted by rtbates

Hey Dave you wrote: a stern drag device aims to prevent this by aiding the rudder, firstly by slowing the boat somewhat so that the rudder is not over whelmed , and secondly by providing a correcting force on the stern to aid in keeping the stern aligned to the drogue and hence the wave.

Is the result of this not having the boat held back allowing the wave to pass under? Is that not the whole idea, keeping the boat OFF the wave face?

Well, my first experience(s) were towing warps, or warps with bits on. This was is very big but fairly regular seas, that were occasionally breaking. The aim was to slow the slewing of the boat so that the autopilot could regain control and the crew could be rested. ( this is similar to the video in the thread past.

In this case the boat was slowed to about 5knots, but still went up and down the wave trains as normal. I just cant see how you "hold the boat back " That would require virtually stopping the boat, and if you stop you loose control.

The second experience was using something similar to a series drogue, though I hasten to add it wasnt a JSD, it was I think home built but not by me. My main concern here was that it really slowed the boat down , like down to a knot or so. Initially this left us feeling very vulnerable to breaking waves ( or even wavelets breaking into the stern. The other issue ( a bit like the video also), was the feeling of helplessness, at those low speeds we couldn't manoeuvre out of our own shadow, you have in effect surrendered control to the drogue. I'm of the school that says active steering is the way to stay alive in a production boat in a big storm. This was in a F9-F10 storm in teh deep Atlantic. ( lots of learning curve)


The problem with all this analysis, is that its terribly case specific, two boats in identical storms, may find very different outcomes. Often what worked for us may not translate to others. Its very hard to form a consistent, "do this, then so that " approach.
Dave

[S/V Alchemy]

Originally Posted by goboatingnow

The problem with all this analysis, is that its terribly case specific, two boats in identical storms, may find very different outcomes. Often what worked for us may not translate to others. Its very hard to form a consistent, "do this, then so that " approach.
Dave

On that we can agree.

Akin to doing the more realistic sort of COB drills (try to get a human weight, half-awash object out of the water with the gear at hand), I suppose everyone should practise deploying these sort of devices at different lengths, etc. to try and establish a) if the device is right for your boat at all, and b) if yes, in what fashion will it be most effective?

Given the cost of even making one yourself in time and money, you'd want to figure out how to get a drogue of this type back aboard as well.

I'd have to think where to stow the thing as well.

[goboatingnow]

Originally Posted by nv5l

His description, while consistent with conventional drag devices, doesn't apply to the JSD.

The video link I posted, as well as plenty of others, clearly shows the wave safely passing under the boat. As the boat begins to accelerate, the JSD applies more and more drag to slow her down and keep her under control. The rudder plays little or no part.

I have no direct experience of a JSD. reading the website, there are things I agree with and disagree with. The JSD seems to be designed for the most extreme situation where the crests break and the drogue prevents the boat being thrown forward and down onto its lee side by the water jet". It would be incorrect to characterise this as holding the boat back so as to let the wave pass under. what it prevents is the breaking crest from accelerating the boat down the wave front.

I would fundamentally disagree with him on his comments that breaking waves don't come from other directions. I personally have seen breaking waves actually travelling in the trough of the primary swell. Funny things happen when a big front goes through, the huge wind shift , then causes a storm sea to overlay on the original major swell direction. This is a very common storm mode of this side of the Atlantic at our latitudes . This is why I believe in active steering, ,often a path has to be traced through the wave train. This coupled with the effects of the continental shelf can generate wave trains from all over the place.

The other issue I take issue with is the comment that the breaking crest does no damage. As a person caught in the middle of several, the answer is Yes and No. It depends on what happens, yes the crest is aerated ( and the dammed boat sinks into it like a sub), but the "jet" is real water and if it falls on the stern , it can do serious damage, taking out hatches and washboards.

All this gear is useful, but its knowing when its useful is the real trick.

Dave

[nv5l]

I'm actually unclear about breaking waves as well. Heaving to is supposed to create a slick of turbulence that breaks up the breakers, so to speak. However, with you stern to the waves, you don't create the wide slick.

Also, assuming heaving to actually works, you still might get a rouge wave from the side like you describe, which would have the same affect. However, I've never heard of that happening, so why should I worry about it with the JSD?

[goboatingnow]

Originally Posted by nv5l

I'm actually unclear about breaking waves as well. Heaving to is supposed to create a slick of turbulence that breaks up the breakers, so to speak. However, with you stern to the waves, you don't create the wide slick.

Also, assuming heaving to actually works, you still might get a rouge wave from the side like you describe, which would have the same affect. However, I've never heard of that happening, so why should I worry about it with the JSD?

I have my suspicions about this infamous "slick". I have all the pardy books and I know they swear by heaving too. I dont beleive it works at all well ( or in fact at all) with modern short kneels. I would never consider relying on heaving too in a survival storm. Yes it works in storms that I personally would still sail on in.

My own experience in trying it, convinced me that modern canoe underbody boats will not stay on the same tack, Hove too. They are inevitably thrown through the wind by wave action and suddenly sail off. Either that or they lie way to far off the wind and you are effectively ahull. Dont like it dont trust it. Yes it works to allow you to have a cup of tea in a rough sea, but not as a survival technique.

Interesting both my towing warps and the drogue seemed to cause the wave to break further back. we used to take bets to see how far the jet would reach us, never did, ( except one, the problem is that one nearly wiped us off the planet!!)

Dave

[cburger]

No boat has ever been lost that has deployed the JSD. Mr. Jordan a retired aeronautical engineer developed the drouge due to his concern for cruisers being lost at sea due to violent storms, not for profit. Drouge was developed by using models in wave tanks, not guesswork and is considered quite a breakthrough for this type of safety equipment. U.S. Coatguard endorsed.

[goboatingnow]

Originally Posted by cburger

No boat has ever been lost that has deployed the JSD. Mr. Jordan a retired aeronautical engineer developed the drouge due to his concern for cruisers being lost at sea due to violent storms, not for profit. Drouge was developed by using models in wave tanks, not guesswork and is considered quite a breakthrough for this type of safety equipment. U.S. Coatguard endorsed.

I don't think anyone has criticised the JSD in any of these posts. Anyway no boat was lost, unfortunately any that did arnt here to tell whether they used a JSD or not. That's the problem with all heavy weather theories, we don't know about the ones that didn't work.

Dave

[nv5l]

Originally Posted by goboatingnow

I don't think anyone has criticised the JSD in any of these posts. Anyway no boat was lost, unfortunately any that did arnt here to tell whether they used a JSD or not. That's the problem with all heavy weather theories, we don't know about the ones that didn't work.

Dave

Good point, but you could use the same logic on a few of your points as well.

As an engineer myself, I tend to appreciate the arguments and evidence presented by Jordan, however, I'm not ready to dismiss the concerns expressed by experienced sailors like yourself either.

[cburger]

Originally Posted by goboatingnow

I don't think anyone has criticised the JSD in any of these posts. Anyway no boat was lost, unfortunately any that did arnt here to tell whether they used a JSD or not. That's the problem with all heavy weather theories, we don't know about the ones that didn't work.

Dave

Boats are lost and crews are recovered all the time. The JSD has been around long enough now that if one had been lost whle using this drouge we sould have heard about it.

[S/V Alchemy]

Originally Posted by goboatingnow

Funny things happen when a big front goes through, the huge wind shift , then causes a storm sea to overlay on the original major swell direction. This is a very common storm mode of this side of the Atlantic at our latitudes . This is why I believe in active steering, ,often a path has to be traced through the wave train. This coupled with the effects of the continental shelf can generate wave trains from all over the place.

The other issue I take issue with is the comment that the breaking crest does no damage. As a person caught in the middle of several, the answer is Yes and No. It depends on what happens, yes the crest is aerated ( and the dammed boat sinks into it like a sub), but the "jet" is real water and if it falls on the stern , it can do serious damage, taking out hatches and washboards.

All this gear is useful, but its knowing when its useful is the real trick.

Dave

OK, now that I am getting a clearer picture of the conditions, I would agree with active steering as well. While on night watch as crew offshore, I have been smacked by a couple of these "no see ums" at 90-120 degrees offset from the prevailing wave train and it's laid the boat over, woken up the skipper and convinced me of the utility of a tether. Either that or the boat, as you've said, can "trip" in 40 feet of bubbles and simply slump into the water while still lurching forward.

Nonetheless, I would rather be going 4 knots than 9 in such conditions, or generally as sedately as would allow full steerage in the dark of night when seeing this stuff is not likely, and therefore whether you can disengage the windvane and steer actively become a little moot.

Squalls of course are different...even at night you can see and hear them coming and radar will warn you in more detail and in advance if you have the means to afford it and the wit to turn it on.

Any safety gear of this type is unlikely to solve every problem one might encounter, but if it is an incremental improvement on towing warps and a fat tire, or if it is more effective than a sea anchor, para-anchor or the Gale Rider type of single, large stern drogue, then it's worth investigating.

[w1651]

Everything I have read says to use a 5/8 nylon line that is at least 16 or 17 times as long as the stern is wide. You also use two attachment points on the stern for that line with the drogue attached in the middle off the stern.
As the boat goes up a wave it slows and as it falls down the other side from the top the drogue applies ressistance and slows you down allowing the wave to pass below the boat.
I would definately reinforce 2 large cleats that are mounted on the stern of the boat with large thick backing plates to handle the loads.

[estarzinger]

Originally Posted by cburger

No boat has ever been lost that has deployed the JSD.

Actually this is NOT true. I know of at least one. There was a boat (single hander) half way between south Georgia and Cape town 3 or 4 years ago that was lost with a JSD deployed. The boat was knocked down (with the drogue deployed) and the mast was damaged and a mayday was put out and a freighter came and took the sailor off.

We like and use drogues. However, there is no silver bullet. ALL the techniques available have drawbacks and boats have been lost while using ALL the various techniques.

You need to develop a good feel for your boat and know when it is stable in the water and when it is not. You keep trying different stuff until it feels good. After a while your accumulated experience will tell you what is most likely to work with your boat in the specific conditions, but you still need to be keeping up with the feel for the situation, as what is good at the start/middle of a storm is often not good at the end. Many many boats have come thru 'the worst of the storm' only to be lost near the end as the wind has dropped and shifted. It's common to wallow and get caught by a cross wave and rolled, unless you stay on top of the situation and evolve your technique as the conditions evolve.

[maxingout]

I carried a Jordan Drogue but never used it. I once used an Abbott Drogue to good effect in an Atlantic storm with 50kts wind lasting several days.

ABBOTT DROGUE

Here is what I know about drogues and parachutes.

Blue Water Catamaran - Exit Only Sails Offshore Around The World.* Captain Dave - Privilege 39

[S/V Alchemy]

Originally Posted by estarzinger

We like and use drogues. However, there is no silver bullet. ALL the techniques available have drawbacks and boats have been lost while using ALL the various techniques.

You need to develop a good feel for your boat and know when it is stable in the water and when it is not. You keep trying different stuff until it feels good. After a while your accumulated experience will tell you what is most likely to work with your boat in the specific conditions, but you still need to be keeping up with the feel for the situation, as what is good at the start/middle of a storm is often not good at the end. Many many boats have come thru 'the worst of the storm' only to be lost near the end as the wind has dropped and shifted. It's common to wallow and get caught by a cross wave and rolled, unless you stay on top of the situation and evolve your technique as the conditions evolve.

I would imagine part of the reason for this is because of fatigue and relief leading to inattention. This is a never-ending and perhaps never-to-be-resolved dilemma, because one of the advantages of hoving to is that you can rest and be therefore in better shape having not been on deck actively steering for perhaps 12 hours. Of course, the disadvantage is that some boats don't heave to well, and you essentially leave the boat to its own devices, which may involve nasty surprises.

Your advice, however, is very good, Evans. Know the boat, know the safety gear and know the likely limits of both and of yourselves when using them. If you haven't played with this stuff in sub-survival conditions, you could make things worse for yourselves just when you think you've got a golden ticket to surviving a storm. The human element is the biggest variable, not the gear in most cases, which is why some sailors don't need or want things like JSDs, because they have the skills and the boats that will answer to towed warps, sea anchors or heaving to without a JSD (or they never encounter the conditions that would test the boat or their seamanship.)