Have had to watch this twice but think I understand. The coloured sail twist diagrams were fascinating. The AC back of the boat camera only shows the traveller so the changes to the rest of the sail is excellent. Love this geekery.
@MozzySails Cunnigham was really interesting as a radial sailor. But it's the weighting of the difference I found educational. Are you, tom and darth vader all engineers. Physics assumptions suggest so.
Oh, it's easy to find: Type in a m Type in an o Type in a z Type in a z Type in a y Type in a s Type in an a Type in an i Type in a l You got the concept??? 🙂
Great stuff, you're quite resourceful providing us with computer animations plus a mechanical mock-up of the INEOS traveller system. Impressive and well done!
Sometimes I have to build something out when I can not visualise how what I am seeing actually works, thank you for going through the process with us because I couldn't see it either.
I was at work, watching this at 1.75 speed in a small window. I only got about 3 mins in before I had to stop, put it back to normal speed and pay full attention!
Quite a few cats that have a single line traveler system (like a self tacking jib) would work very similarly. Particularly as many would sail a lot with mainsheet. E.g nacra 17s. "Split tail traveler"
Two questions. 1) About curved track. I get that a straight track implies that as traveller goes down, friction increases, and a fixed main sheet would necessarily tighten the leech. Undesirable. Slightly curved track can cancel that effect. Would it make sense to have an “Uber” curved track, so traveller down simultaneously slight induced twists? 2) If track is a constant distance from gooseneck, I’m not sure why it needs hinge.
1) you could do, but the risk with over curving the track os that the car doesn't want to return to the middle, which where they are trimming up past centreline would be an issue. 2) they don't have a boom and therefore the sheeting angle on the mainsheet changes a lot. If the track didn't pivot the change in sheeting angle would lead to the car being side loaded and friction
Love it Tom! Reminds me of sailing the Tempest on Ullswater, and pulling the moveable pulley system centre traveller over each tack, as it gets too windy and Dad too lazy just ease off the traveller rather than heavy mainsheet more effective on big blowy days and less work on a long upwind. And in light winds could pull the traveler further over to windward. Really enjoying your videos. Have a great Christmas. James :)
Great explanation of the technology used. The 2D diagrams of the sail controls are brilliant. A 3D model could be used to show how the controls work independently and in unison to change the twin skin sail shapes. We need a 3D modeller to donate some time. Great work Mozzy
Your final iteration seems to make sense - that floating tie-bar should always move all the way to windward after each tack/gybe and stay there. Self-tacking but with the ability to independently (pre)set the stop point on each tack. Would definitely use less power than driving the traveller across during the manoeuvre. But... Squinting at the sailing clip at about 5m45, when they let the traveller down to leeward (all the time staying on starboard tack), I seem to see the port/leeward end of the tie bar moving to windward. Starts about two hinge segments from the end, moves about another two segments inwards. I can't figure how this could happen, but I'm sure I can see it. I can't pick out anything on the starboard side.
I think it could be elasticated. So that it 'takes up' slack from the leeward side when the traveller is eased. This would decouple the two rams so they don't have to be run in complete sequence
@@MozzySails Of course! The bit I was missing is that it isn't actually under tension due to the traveller loads. It can just be a pretty light spring to keep the lines tidy.
Love the diy approach - sometimes it is the only way. Thanks for the effort. I am slowly making my way back to racing after some health upsets, my races tend to last days though! Happy xmas.
I don't think it's a "differential" or self-tacking main. I think it's just a bungee to take up the slack when they drop the traveler. If you coupled the rams like that you'd probably break something if you had both rams on all the way.
I could think that another effect of this system is that once you release the traveller or turn into a tack, it doesn't slam onto the stop on the leeward / new leeward end of the track.
In the picture at 4.34, both rams are fully extended and the traveler line is tensioned. If one ram starts to retract, where does the 3x extra line come from if the opposite ram is already fully extended? I think we are missing something still. I wonder, what is the silver tube running across the web section of the traveler itself? Sensor conduit or hydraulic line?
I think the silver tube is a sensor, there seems to be a magnet zip tied to the traveller car which it's reading the location of. I think the differential line could be elastic. So it takes up on both sides when both are slack, then only takes up on the leeward side when the windward side is loaded. So it basically decouples the rams from having to work in synchrony and takes up spare line from the leeward side
I was thinking the same, looks a lot like Corey, to allow clew/foot tension control with the traveller hinge. But this doesn't look strong enough for the forces involved.
Your videos on these boats is great, thanks so much for explaining these complicated beasts. Do you have a video explaining the changes between last year and this year?
I think the part which you say is a take up system, is actually so they can tack/gybe and then end up with the same traveller setting on the other tack/gybe
Without kicker or downhaul there is insane power to the traveller. Here it runs free, more hydraulic power for foiling. Question: The Cunningham thing is really eight tons?
Planet Sail did a good interview with Paul Goodison here which is where I lifted that attribution to him from. They also mention 5-8 tonnes of Cunningham load. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7krheAN3i8o.html
@@jan-udosiefkes Basically you need the same load on the Cunningham than on the clew to avoid the sail to entangle (possibly me not knowing the English term: putting the sail material out of angle)
I think they'll put it recess in the deck like Luna rossa, american magic and ETNZ have done. I guess they just put it on deck so its easy to access and modify on this test platform
@@MozzySails Ah, thx. Significant structural modification, if unplanned, but that would explain pivoting track, which perhaps could be achieved simply with bearing design and soft shackle.
Great diagramming in the video! I'm still a little confused by the main trimming on these things. I do think there's a better way, need to deep dive into the rules before I voice my idea.
Hi Mozzy, fantastic analysis of the poms ,I’m a kiwi , and constantly fascinated by how bad the poms are at the americas cup !!or is that changing with the Mercedes’ approach!! Maybe I’m missing something here but all that gear in my view is a red herring just to get you off track . My view on this is that there is a different system under the stern not seen yet , I mean fair dinkum just on windage drag it must muck up the air flow off the back of the boat negating the accuracy of their supposedly so sophisticated sensor systems .. The recon team commented on their boat in the light in displacement mode looked sticky and unstable ? Come on poms have you not learnt anything form the last cup ? Mozzy see if you can see deeper into their smoke screens and mirrors mate
I actually don't think there is anything else hidden. It's pretty ugly having it all on deck like this, but it looks like it's system at least three of the other teams are already using. I guess their thinking is that it's quicker to alter/ service
@@MozzySails It's not like there's anything else about that hull that suggests they've tried to optimise for aero drag at this stage, so agree, may as well make it easy to access. "Design a carbon fibre monocoque structure which slips through the air easily" may well be something a team full of F1 designer/analysts is comfortable doing entirely in simulation, vs needing to calibrate models for hydro and sailing loads.
I guess this allows the traveller to be 'self tacking' but allow it to not be set symmetrically on both sides. Do we know if the rams are being adjusted the same amount (meaning that the traveller position will be symmetrical on each tack) or one pulled on more than the other (meaning that the traveller will be assymetric on each tack). I'm struggling to see how this is better than using one central ram and using a system similar to a solo dinghy traveller (the self centring version) unless of course the rams aren't being used the same amount on both side...
Great content. With a system like that you’d think they’d need the ability to control the amount of differential? As wind strengths change surely the start position of the main after each maneuver would be different?
I think black line across the back is elasticated. So it takes up slack from the leeward side as the windward ram moves. Then, before the tack you can pull some of that slack back in to the system with the leeward ram. Whatever line you leave in the tack up as you enter the tack will be the amount the booms drops down on the exit
Why can't the hydraulic accumulators be replenished by the sailing process? Possibly a turbine at the end of each foil or sail to harvest some of the end vortex?
Obviously Ineos are not too worried about aero drag from the hinged traveller...or maybe they just couldnt be bothered engineering it into the deck like LR & AM.
I thunk the latter. There is lots just bolted on to the deck, which for easy reconfiguration on a test mule makes sense I guess. Not pretty, but means we get to see lots of tech 😀
I’m not sure if im missing something (i must be) but it seems like you can’t trim the traveller above the centreline with this design no? I remember in the last AC they often raised the traveller to windward especially on the downwind legs
The concept of the diffential isn't new , I've certainly never seen the way ineos have done it ,many many dinghies have this sort of diffential when they tack ( lasers and nearly all dinghies with a free moving traveler )
Yeah perhaps I’m not being clear. I’m wondering if anyone can imagine a similar system where the weather sheeting position of the car is replicated to weather on the other side of the tack. Effectively it would be fighting the load on the traveller car rather than using the load to replicate car position.
I think probably tow things. 1) getting fast enough rams... not that fast enough rams don't exist, but on the AC75 all sail controls are powered from the same hydraulic accumulator. So high tension items like mainsheet and Cunningham need to operate with similar flow rates to comparatively low tension controls like traveller. So to then get the actual speeds you need you have to use inverted rope purchases unless you end up using up to much oil volume and pressure unnecessarily. 2) might be a space / weight issue. Better to have the heavier systems further forward then linked with comparatively lightweight ropes and pulleys