Jordan Series Drogue Attachments And Launch System
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More Articles From Online Book: Heavy Weather Tactics:
- Introduction—We Need A System
- Goals For A Heavy Weather System
- Rogue Waves Are Not Bad Luck
- Just Get a Series Drogue Designed By Don Jordan…Dammit!
- Jordan Series Drogue Attachments And Launch System
- Alternatives to Chainplates For Drogue Attachment…Or Not
- Jordan Series Drogue Retrieval System
- Jordan Series Drogue Retrieval—An Alternative From Hal Roth
- Series Drogue Durability Problems
- Battle Testing a Jordan-Designed Series Drogue—Round 1
- Battle Testing a Jordan-Designed Series Drogue—Round 2
- Real Life Storm Survival Story
- Series Drogues: Learning From Tony Gooch
- Series Drogues: Learning From Randall Reeves
- Retrieval of Dyneema (Spectra) Series Drogues Solved
- Heaving-To
- When Heaving-To Is Dangerous
- Stopping Wave Strikes While Heaved-To
- Determining When Heaving-To Is Dangerous
- Transitioning From Heaved-to To a Series Drogue
- Storm Strategy—Fore-Reaching
- Surviving A Lee Shore
- Storm Survival Secret Weapon: Your Engine
- Storm Survival FAQ
- Companionway Integrity In A Storm
- Q&A: Safety of Large Pilothouse Windows
- Summary And Conclusions For Heavy Weather Book
I found your series on the Jordan Series Drogue very interesting. I have bought a drogue, but now am faced with the problem of attachments.
My boat, a Victoria 30 (aka Morris Leigh), is an aft-cockpit, 30-foot double-ender. The drogue’s instructions indicate the attachment points should be at the stern and as far apart as possible. To separate the attachment points would mean coming some feet forward, I think. I seem to have two alternatives: mount a plate on top of the cap rail, with bolts through to an interior backing plate; or mount it on the sides of the boat (solid fibreglass) just below the cap rail with bolts again through to a backing plate.
Have you any thoughts on these alternatives or other suggestions as to attachment points given my boat’s profile?
I’m sorry, I have no engineering training and I can’t opine on a specific mounting situation, particularly without seeing it.
I do sympathize with the boat owner trying to get good advice on mounting options, since there are a lot of people out there, particularly in boat yards, who will be only too ready to render an opinion without the training to do a qualified analysis.
Really, the only right way to do this is to consult a qualified naval architect or engineer. You may wish to try Ian McCurdy of McCurdy and Rhodes. Ian’s time will, I would guess, cost you a few hundred dollars, but you will know it’s done right.
Or attach to a single point on the stern, as close to the centerline as possible, and skip the bridle? Ask Jordan manufacturers about this, they might have useful input. It will be simpler without the bridle.
Graham:
Did you ever solve your attachment point problem with your double ender? I also have a double ender (a Tashiba 40) and I trying to figure out how to construct bridal attachment points
John, did you put spacers on the pins of the shackles that attach the bridle to the hull? If not, might any yawing put an awkward stress on the pin where it goes through the tabs?
I’m asking because I am purchasing a JSD from ACE and plan to make tabs similar to yours (a bit less beefy, as I have a Nordic 40, ~11T displacement). I am considering making a slot in the tab so that a shackle can be inserted and have the rounded part of the shackle ride in the tabs. This would allow the shackle to turn laterally as the boat yaws. The downside is it would weaken the tab somewhat. Also, perhaps a boat running on a bridle doesn’t yaw all that much and my concern is moot.
Your JSD series of articles have been tremendously useful, thanks.
No I did not put spacers on the shackle pins. Having said that, it might be a good idea since the boat will certainly yaw about on the drogue.
What I did do was verify with the shackle manufacturer (Crosby) that the pin could take the max load (75% of boat displacement) without deforming with that bearing surface.
Your idea of having a slot so the shackle can be turned around might be a very good one, although this will require a much larger chain plate to insure that there is enough meat either side of the hole.
If in doubt, I would get an engineer to help you spec the plate. The loads here are potentially prodigious. In fact, even though I did a bit of maths on our plates, I think I may get an engineer to look at my design, just to make sure I got it right—this is no place for unqualified guesswork.
Thanks, John. After looking at this a little further, and getting feedback from a couple folks on the CSBB forum, I think I will follow your design but with the following modification: I will triple (or so) the surface area of the tabs aft of the hull, using sealing welds, to build the thickness up to the width of the shackle. This will hold the shackle in alignment so that the entire length of the shackle pin will bear on the surface of the tabs (it also strengthens the tab). I’m afraid that if the shackle pin has room to turn athwartship in the hole, the pin will only have a thin corner surface to bear on. I’m still hoping to get an engineer to look at it and will post what I find. Look forward to any further thoughts you may have. Thanks again, Max
Hum, I’m no engineer, but I would worry about building up the tangs with weld bead, if that is what you mean. As I understand it, that kind of heating can make changes to stainless steel. Why not just shim the shackle with large washers or plates?
Having said that, I’m not sure about this whole direction since shimming the shackle, will, I think, add to the back and forth bending load on the chain plate itself, as well as the load trying to strip the screw thread on the shackle pin. We might be outsmarting ourselves here.
Keep in mind that I spoke to engineering at Crosby and they were happy with the loads and the bearing surface of my plate.
And the more I learn about the fatigue problems exhibited by stainless, the more nervous I get about this kind of guesswork. Given that this is your (and mine) last line of defense, I’m more and more sure that I will get an engineer I can trust to look at the whole assembly on our boat. I would suggest you do the same before welding.
I would also be very careful of information you are told on a forum—lots of “experts”, not much knowledge.
I communicated with a sailor who has deployed the Jordan on three occasions. He encouraged me to install heavy duty cleats to secure the drogue (along with heavy chafe gear obviously). He likes to be able to adjust the bridles to square the boat to the oncoming seas.
I also consulted with Dave P. at Ace Sailmakers, and with a structural engineer, and will likely go this route. I found a pair of solid 316SS cleats, way oversized for my boat, that look very similar to those in your pic above, and will bond in backing plates of G10. My cleat is right at the transom, with no toe rail or other obstruction, so I may have a cleaner run for the bridles than do many boats.
This attachment method gives up some advantages of the tangs, and introduces more danger of chafe. On the other hand, it requires no shackles or thimbles, which was one of my concerns as noted above.
Sounds like you have a good plan. Interesting idea about adjusting the bridles—nothing trumps real world experience.
As you point out so well, every system is a compromise with pros and cons.
One other advantage I can think of: If you make the bridles a bit overlength, if you see chafe developing you could ease them a few inches to “refresh the nip”.
I think the reason that Don Jordan was so against cleats was that very few boats have ones that are strong enough to lift 3/4 of the weight of the boat. Even our massive cleats are not that strong because of the weight of our boat (52,000lbs), which is why I went with chain plates.
John:
Thanks for the reply. I may ultimately have to take up the engineer option. The drogue is a piece of kit I hope never to use, but if I ever do, I’d like it to work.
Nick:
Thanks for the suggestion. A single point mounting might be workable, but likely would come in conflict with my Aries wind vane. I did contact Ace, but they replied that they didn’t get into this area.
Nick did you figure the attachment point out for your boat. I have a qbaba 30 with a monitor vane and have just started working out how to do it. Rich
Hi Rich,
Not sure if this will help you or others with hull shapes that make side mounted plates problematic. We have a complex curve on the hull side on each quarter, meaning any side mounted plates would need to be twisted, and then bent, to fit snugly in place without movement. We thought this would be way too hard to achieve.
Our solution, was to cut off the last 400 mm of top mounted teak cap rail, that covers our hull / deck joint and then mounting the new plates in their place. My boat builder friend who did the work and fabrication for us recons we could lift the whole boat on just one of the plates.
By sizing these new stainless plates to match the dimensions and radius of our cap rails, and with recessed bolts concealed under the plate and through bolted and secured from under the deck, they look just like “bought ones” and we have had as many admiring comments about how smart they look, as we have had questions about what they are for!
Perhaps if you have a similar cap rail or hull deck joint, you could fabricate similar top mounted insert plates that protrude outside the line of the hull, providing the lugs that could take a bridle?
I hope my description makes sense.
Rob
Thanks Rob can you please email photos to moc.liamg@09detsidrahcir
Sure, I will have to take some close-up photos when I am next aboard – it’s summer here (down-under) so shouldn’t be too long.
Rob
Hi Rob,
That sounds like a great solution to the curved hull problem, thanks.
Thanks Rob. I live 30 miles from Ace sailmakers so making a trip to visit Dave this week. To see the drogues. My boat is small with a very bust cockpit so appreciate your effort. Rich
Rob,
I like the sound of that design, also. Would you send me a copy of the photos as well?
Thanks,
Jack
moc.liamg@ecirplj
Hi Graham did you ever figure out your attachment points. I have a 1978 ta-shine baba 30 footer and am tackling the install of attachment points for a jsd and what to use. Any thoughts and pictures if you have them, ps can we post photos here at ACC thank you, Rich s/v Lily Bermuda