Dyneema has everything going for it for a series drogue except one important thing, flexibility. Given how unlikely the highest snap loads are this might be acceptable.
Great video, James. Super important topic. Something I've wondered about is why couldn't you have the chain plates for the drogue a bit farther forward. Wouldn't this allow the boat to pitch forward more and take the waves at a better incline?
Interesting idea. I assume your point is that if the transom were not held at a downward angle there would be less danger of waves filling the cockpit. I don't know enough about the dynamics involved to be certain but I suspect you want the pull down on the transom to prevent pitchpoling and that the bow is pitching down far enough as it is. Also, if the chain plates were far enough forward to make a difference in pitch angle then it'd be too noisy as you tried to rest inside as the bridle legs slapped the hull like banging a drum each time one cycled from slack to tensioned as the boat yawed.
Interesting point but I suppose the more they move forward you have a risk of A: chaffe and B: A big breaker pitch poling the boat around the axis of the chain plates. That would be horrific. Since the series drogue sinks between waves and then rises to the surface when pulled then the boat will accelerate when struck by a breaker and surf for a few seconds which should allow the stern to up end. Only for a second or two but it is that rising and sinking motion that is key to the design.
Excellent and really informative video - thanks, James. I'm building my own JSD, so I have a pair of related questions: Your chainplates are smaller and neater than many. How did you determine their dimensions, bolts size, number, spacing? Given that the bolts transfer JSD loads up to 'Design Load' into the hull structure, how did you determine whether the existing layup could cope with the 'Design Load' without damage? If you added reinforcement inside, what did you add and how did you specify it against the expected loads?
Thanks for your comment. Since I'm not an engineer I guessed at the loads and strengths of materials involved based on many years working on boats. These chainplates are smaller than most you see probably because the boat is smaller and the drogue has less cones than the others you've seen, which means less loads. How much less was my guess. These chainplates are a stronger improvement to the 1/2" u-bolts I installed earlier on my own same model 28' boat. My guess is that the loads of an 85 cone drogue on an 8,000 lb boat are not likely to exceed 3,000 lbs per chainplate. The corner of the hull and transom is a natural strong point. I also add a 1/4" or 3/8" G10 backing plate glassed inside on most boats. In this case, since the stern is an outboard well locker that is watertight from the rest of the boat, even in the unlikely event the chainplate was ripped out it would not endanger the boat. If the stern was not sealed then I might consider something stronger for increased safety factor. The three bolts here were spaced about 2" apart. For a bigger boat with 100 cones that might be lengthened to say 4 bolts, 3" apart. If in your research you come up with some useful guide on how strong is strong enough then we'd like to hear about it.
Im an engineer specialised in marine and metallurgy fields. The main thing you need to know is shear strength of bolts and the bearing load on the fibreglass. The metal is widely known and easily calculated. The fibreglass is a function of resin to glass ratio and this would need to be estimated without doing pyrolytic testing of the hull sample in a laboratory. So you would normally take a conservative estimate and then provide factors of safety, which tend to range from 2-6 in most engineering structures. You need to make it strong enough to survive a once in a lifetime load. For a jordan series drogue, that load is estimated at approx 70% of loaded boat displacement on each chainplate due to the action of the bridle and its angle providing load sharing between two chainplates. I did some calculations for my boat which is 15,000 pounds displacement, and have it in front of me. But I cannot upload pictures, so basically, i designed some stainless plates and also some aluminium plates for aluminium hulls. The chainplates in this video may be acceptable for the boat video, but would need a few more bolts for safe shear loading in a boat of 15,000 pounds. Keep in mind that dyneema has very low stretch (elasticity in engineering terms) and therefore much higher dynamic loadings than if you used polyester. Sometimes that can work against you and you can cause failure in dyneema which equivalent strength polyester would survive in a dynamic application. This is related to impulse in physics if you're interested to look it up.
Thank you very much for the excellent video. Just wondering, what is the main reason why you would make your own instead of ordering it at OceanBreak? Thank you very much.
I wanted to use my own dyneema and other parts I had in stock, assemble it to my specs rather than theirs, and save some money by DIY assembly. If you try to order one completely finished then you need to either accept their materials and design or specify to them the specifics of what you require. But I've found over the years that whenever you ask someone to custom build something different than their their standard design, you run the risk of miscommunication or otherwise having it botched.
Excellent video, thank you. ⛵️ Have you tried deploying the drogue yet with the vane rudder lifted and the tiller/rudder tied off? If so, was it better/worse? And was retrieval easier?
The local sailing I've done in recent years has not called for deploying a drogue and I haven't done further tests. I had no problem with the windvane connected and it did not affect retrieval but to better protect its servo rudder from getting snagged, in future I would pull it up first. Just because the rudder and tiller were moving around in that video does not mean that had any affect on anything since the boat speed was very slow and the boat was firmly held by the drogue.
Was reading something skip Novak said you only need a drouges warps or whatever on small light weight boats he was goin around the horn on his super heavy aluminum boat said never needed it on thr big boats he sails
Skip said that based on having a significant crew that is capable of doing watches and all which are experienced with sailing / surfing breaking waves in the dark. Most cruising boats don’t have that experience on board and even if they did, couldn’t stay at the helm full time. The series drogue allows you to go down below safely. I’ve got a lot of experience in big wave conditions but in stressful surfing conditions where a knockdown could happen, I’m knackered after and hour and then my concentration isn’t on top form. Skip also considers “heave-to” a satisfactory storm tactic… which is fine until the breaking waves get to a sufficient size. It absolutely can’t be relied upon in serious situations. I’m basing these comments on my 43ft (17t) boat whereby I have used a series drogue in a storm.
You can email me through the contact button on the bottom of the page at atomvoyages.com. I do have a drogue for sale listed at: atomvoyages.com/boats-and-equipment-for-sale/
Perfect timing, I just got a quote for 105 cones in order to build my own JSD. Thanks for the excellent video James!
That is good timing and I hope the video is helpful. I guess you have a bigger boat so maybe 3/8" (10mm) dyneema is required.
@@atomvoyager Haha not bigger just husky! I have a Pacific Seacraft Orion, empty weight is 10,000# so loaded perhaps 12,000#.
Thank you so much for providing with such detailed informations on how to implement drogue ancre and how deploy it, This is so helpful
A very informative video. Thank you
I really, really wish you would enable subtitles on your videos so that I could more easily watch them at work instead of doing my job.
Excellent video, James. Many thanks for your content.
Thank you for this very informative video, James. I appreciate the time and knowledge you've shared.
Really clear explanation. Many thanks Mike
Dyneema has everything going for it for a series drogue except one important thing, flexibility. Given how unlikely the highest snap loads are this might be acceptable.
Thank you for sharing this. Very informative and helpful.
Fantastic!! Thanks for producing this video.
Outstanding video, thank you for sharing.
Great video, James. Super important topic. Something I've wondered about is why couldn't you have the chain plates for the drogue a bit farther forward. Wouldn't this allow the boat to pitch forward more and take the waves at a better incline?
Interesting idea. I assume your point is that if the transom were not held at a downward angle there would be less danger of waves filling the cockpit. I don't know enough about the dynamics involved to be certain but I suspect you want the pull down on the transom to prevent pitchpoling and that the bow is pitching down far enough as it is. Also, if the chain plates were far enough forward to make a difference in pitch angle then it'd be too noisy as you tried to rest inside as the bridle legs slapped the hull like banging a drum each time one cycled from slack to tensioned as the boat yawed.
Interesting point but I suppose the more they move forward you have a risk of A: chaffe and B: A big breaker pitch poling the boat around the axis of the chain plates. That would be horrific.
Since the series drogue sinks between waves and then rises to the surface when pulled then the boat will accelerate when struck by a breaker and surf for a few seconds which should allow the stern to up end. Only for a second or two but it is that rising and sinking motion that is key to the design.
Excellent and really informative video - thanks, James. I'm building my own JSD, so I have a pair of related questions:
Your chainplates are smaller and neater than many. How did you determine their dimensions, bolts size, number, spacing?
Given that the bolts transfer JSD loads up to 'Design Load' into the hull structure, how did you determine whether the existing layup could cope with the 'Design Load' without damage? If you added reinforcement inside, what did you add and how did you specify it against the expected loads?
Thanks for your comment. Since I'm not an engineer I guessed at the loads and strengths of materials involved based on many years working on boats. These chainplates are smaller than most you see probably because the boat is smaller and the drogue has less cones than the others you've seen, which means less loads. How much less was my guess. These chainplates are a stronger improvement to the 1/2" u-bolts I installed earlier on my own same model 28' boat. My guess is that the loads of an 85 cone drogue on an 8,000 lb boat are not likely to exceed 3,000 lbs per chainplate. The corner of the hull and transom is a natural strong point. I also add a 1/4" or 3/8" G10 backing plate glassed inside on most boats. In this case, since the stern is an outboard well locker that is watertight from the rest of the boat, even in the unlikely event the chainplate was ripped out it would not endanger the boat. If the stern was not sealed then I might consider something stronger for increased safety factor. The three bolts here were spaced about 2" apart. For a bigger boat with 100 cones that might be lengthened to say 4 bolts, 3" apart. If in your research you come up with some useful guide on how strong is strong enough then we'd like to hear about it.
Im an engineer specialised in marine and metallurgy fields. The main thing you need to know is shear strength of bolts and the bearing load on the fibreglass. The metal is widely known and easily calculated. The fibreglass is a function of resin to glass ratio and this would need to be estimated without doing pyrolytic testing of the hull sample in a laboratory. So you would normally take a conservative estimate and then provide factors of safety, which tend to range from 2-6 in most engineering structures. You need to make it strong enough to survive a once in a lifetime load. For a jordan series drogue, that load is estimated at approx 70% of loaded boat displacement on each chainplate due to the action of the bridle and its angle providing load sharing between two chainplates.
I did some calculations for my boat which is 15,000 pounds displacement, and have it in front of me. But I cannot upload pictures, so basically, i designed some stainless plates and also some aluminium plates for aluminium hulls.
The chainplates in this video may be acceptable for the boat video, but would need a few more bolts for safe shear loading in a boat of 15,000 pounds.
Keep in mind that dyneema has very low stretch (elasticity in engineering terms) and therefore much higher dynamic loadings than if you used polyester. Sometimes that can work against you and you can cause failure in dyneema which equivalent strength polyester would survive in a dynamic application. This is related to impulse in physics if you're interested to look it up.
Thank you very much for the excellent video. Just wondering, what is the main reason why you would make your own instead of ordering it at OceanBreak? Thank you very much.
I wanted to use my own dyneema and other parts I had in stock, assemble it to my specs rather than theirs, and save some money by DIY assembly. If you try to order one completely finished then you need to either accept their materials and design or specify to them the specifics of what you require. But I've found over the years that whenever you ask someone to custom build something different than their their standard design, you run the risk of miscommunication or otherwise having it botched.
Excellent video, thank you. ⛵️
Have you tried deploying the drogue yet with the vane rudder lifted and the tiller/rudder tied off? If so, was it better/worse? And was retrieval easier?
The local sailing I've done in recent years has not called for deploying a drogue and I haven't done further tests. I had no problem with the windvane connected and it did not affect retrieval but to better protect its servo rudder from getting snagged, in future I would pull it up first. Just because the rudder and tiller were moving around in that video does not mean that had any affect on anything since the boat speed was very slow and the boat was firmly held by the drogue.
Was reading something skip Novak said you only need a drouges warps or whatever on small light weight boats he was goin around the horn on his super heavy aluminum boat said never needed it on thr big boats he sails
Here's a real-world deployment. The boat's 43' and 18 tonnes. czcams.com/video/hwb4dqB6a48/video.html
Skip said that based on having a significant crew that is capable of doing watches and all which are experienced with sailing / surfing breaking waves in the dark. Most cruising boats don’t have that experience on board and even if they did, couldn’t stay at the helm full time. The series drogue allows you to go down below safely.
I’ve got a lot of experience in big wave conditions but in stressful surfing conditions where a knockdown could happen, I’m knackered after and hour and then my concentration isn’t on top form.
Skip also considers “heave-to” a satisfactory storm tactic… which is fine until the breaking waves get to a sufficient size. It absolutely can’t be relied upon in serious situations.
I’m basing these comments on my 43ft (17t) boat whereby I have used a series drogue in a storm.
How can I get in touch with you? Now that you have a new drogue, do you want to sell the old one?
You can email me through the contact button on the bottom of the page at atomvoyages.com. I do have a drogue for sale listed at:
atomvoyages.com/boats-and-equipment-for-sale/