I was sooo confused by the first image showing the cylinders sitting in the green cradle on deck. I'm like, "how TF does that act on the sail?!" It wasn't until 6:00 when we got to see all that gack in situ that the penny dropped! These boats are so damn cool. Thanks for the Video Mozz!
I'm still wondering how the attachment to the track works, since, without a boom, there must be a lot of forward pull from the sail tension on the track.
@@charlestoast4051 Sure. It's not super creative sail control tech, but how they've set up the "traveller car" to resist the tension ripping it off the deck and still be free to move side to side would be an informative bit of mechanical design to see!
@@nickgoodall578 I would assume that it doesn't move freely but is moved with hydraulics. In which case just about any reasonably closely curved track would do (and I think they have calculated it down to 0.1mm, not just thrown some random track in 😉).
Thanks David! I've been I credibly fortunate to do as much sailing this year as I have and the Endeavour was a huge cherry on top. Proper boyhood dream come true!
The cheap and simple way to achieve this and transfer the concept to cruising boats is to have a boom, but a foil curved boom which rotates from the boom hinge point in between the two sail foil skins and where the rotation angle automatically sets the tension as the rotation increases from side to side. The mast should also be mounted on a slightly conical slewing ring plate which directly transfers the loads to the hull on either side (slewing rings are the essential part of excavators that allow them to handle the extreme loads that diggers develop). I find the Hull Shape intriguing. The genesis of this design style is not at all new. See the Shannon ShoalSailor (2004). But the real fore runner of all of these concepts was a design called the Aero Hydrofoil from the 1960’s. I wonder how long it will be before someone attempts a mast head winglet to reduce pressure spill at the head of the sail? I like to remind all of the super sailors that one of the most successful racing yachts was a Ferro Cement yacht, Helsal, which in 1973 achieved the trifecta of line honors, a time record, and winning on corrected time in the Sydney to Hobart Race. A trifecta the held for 35 years. The “Flying Footpath”.
I suspect the separation at the clew is unlikely to be as detrimental as you think due to a couple of reasons (see video 9:13): 1) the air in this area is likely to be turbulent flow and 2) lowering the deck lower moves the problem zone on the sail down further reducing the impact. I'm not sure whether the two skins on the sails are allowed to be connected but you would think if that was allowed, there would be some sort of internal skin to zip the sails together in this area. I'm also surprised the mainsheet ram is not rotated 180 degrees as the arm is much thinner than the ram body, this would also lower the weight in the boat. Thanks for the interesting vid and discussion.
9:22 as an aero engineer, I would call that "wing bit" a control horn. That's what we call similar fittings on control surfaces like elevators and ailerons
The discussion of the "thickness" of the hull is interesting. Parasitic drag increases by the square of the airspeed, or I think apparent windspeed in this case. So the low deck, less frontal area, hull would be better for reducing drag. The interesting thing is that hull itself has to be acting as a wing to help the boat fly. I suspect there is a tradeoff between having a hull that is shallow with low drag and therefore does not produce much lift vs. one that is thicker with more drag but helps the boat to fly. The complexity is pretty mind boggling.
a bit off topic but would it be possible for you to compare what the advantages and disadvantages of the wing sail used in previous cups compared to the double skin sails used now?
The solid wing sails are pretty fragile and if you recall the initial thinking with these new AC foiling monohulls was that they were likely to capsize, hence the original aim to be self righting. So if you are going to capsize you don't want to shred your wing. The performance isn't quite at the same level but it's certainly better than a single sail.
@@sailtastic Yes, and there's also the weight factor. The AC75 mainsails are much lighter without need of the complex mechanical parts of the solid sails. If the AC75 is more prone to capsizing, the possible effect on the center of gravity was definitely a consideration.
Fascinating discussion. One has to assume that trades between 1 - larger but smoother faired upwind frontal area and smaller sail area down low, versus 2 - smaller faired frontal area (but more turbulent with beam protrusions) and lower sail center-of-effort were made. Dragging these big ugly high skin area hull shapes through the air must really eat up the available power from the sails.
In the previous Cup we ran a VPP model (quite crude) and the foils produced the overwhelming majority of the drag. That's not to say a few % can't be made from aero drag
Amazing content! Glad you are back at it, keep up the great work. I wonder even if these are the ac40 test boats, if you are willing to do a hull comparison between the teams...very different designs out there!
It looks like more teams will be emulating some of the key design features of Te Rehutai with sound reason. Luna Rosa has adopted the dropped deck feature and it's a good guess Alinghi will follow suit now that they've gone boom-less. It will be great to see Te Aihe optimized with further development. I always liked the lines of this yacht. The fat clew might not be as bad from an aerodynamics perspective as it appears. Those familiar with aerodynamics theory will be aware of a Kamm tail. It's a truncated airfoil that generates controlled turbulence in applications where a full length airfoil is either impractical or restricted by regulation. It's heavily used in modern pro cycling because the UCI has strict rules governing aerodynamics of components. It's also advantageous in certain yaw angles, which may or may not apply to the speeds the AC75 is capable of. This subject is very complex and I'm by no means an expert in fluid dynamics, but wondering how much of an actual detriment the fat clew is aerodynamically?
I was thinking about the clew thickness. It doesn't strike me as aerodynamically optimal. Would it be possible to relocate the ram under the deck near the mast? If you fix one end to the traveller and then use a block on the clew and in the mast to route a (presumably low stretch) control line? As others have commented, it's good to see you back. edit - on reflection, using a crank located between the clew plates might allow the line to be routed directly down to the deck which would prevent the line messing up the upwind sail surface. You could then run the line through a below-deck block toward the mast foot. On further reflection, the entire traveler system could be rigged backwards with the running end connected to the clew and a below deck block running the main sheet to the foot of the mast where you could install the ram.
In early November we'll be posting our first monthly recon teams where we'll present tech situation and sailing time for each team. Aim is to do these monthly right up to AC37
I should have added that the fore runner of the Shannon Shoal Sailor was the Dutch Sailing Barge, and the reason why the Dutch were so far ahead as ship builders was because of the Dutch Timber cutting Windmills. Technology wins every time, and complementary technology is even better.
I sailed a Nacra 5.8 Catamaran for years with a boomless main that swept the deck with an adjustable clew, way more sail trim adjustments than my Inter20 with a boom
If most are doing it I assume that extra drag and fat clew are worth the benefits - lowered sail/deck/ centreOE etc. Never will know but I wonder if TNZ held back development last cycle and they had cleaner and more efficient set up. Silly question, is drag more relevant up or down wind in this class? Thanks for the insights
I though that was an obvious question but then I threw some ballpark numbers in an apparent wind speed calculator... 45 degree upwind and 135 degree downwind angle with 20kn upwind speed and 50kn downwind speed in 20kn wind... The difference is only 1.5kn. If you have time to look up actual wind speed, boat speed and direction data and calculate more accurate numbers, let me know what you come up with because this is a bit interesting.
@@AnttiBrax thanks for your response, that seems like a negligible difference. I think I’d be out of my depth at a quick rate if I started throwing numbers about. But I am keen to learn, albeit at a high level/overview. Have a great weekend
General pattern is that boat designs become more similar. Probably your discussions said that lowering the sail down as low as possible generates notable net gains.
How about a bendy boom. i.e. rigid vertically but bendy laterally. Obviously I no nothing having only sailed a Mirror dingy but loving all the amazing design problems. The Americas Cup has everything! Will be glued to your channel for the rest of the years, a big thank you.
I like the “in clew” sheeting system, but don’t like the ram and gubbins to control the mast which along with the fatter clew does cause aerodynamic problems. Having a slimmer deck also allows more sail area, but I wonder if it’s not better to have a completely smooth aerodynamic laminar flow deck shape to turn the whole boat body into one big uncluttered wing with less hindrance to the upper, low pressure surface?
Great analysis! I'm wondering if there's an aerodynamic advantage for Alinghi, Luna Rossa etc in having a lowered deck? Apart from the wing "thing" by the mast rotation this probably leads to less frontal surface to cause head-on drag, don't you think?
Is it that a lowered deck is more about being a quicker and easier maintenance access point for the teams than a major performance benefit at this point during testing? One thought on the Clew being wider as a non-issue, if it was viewed from a Kamm tail aerodynamic perspective?
Good insights Mozzie. I am thinking that if that gizmo is on AC40s (which are identical I believe) then it is unlikely to be on the AC75. I further suspect the NZ yacht will be totally different from last regatta. In particular, it won't have a jib as apart from the start it actually slows the yacht down at high speed and it will focus on high speed ahead of everything else as it will really be a plane. All this should be the trigger to get back to real yachts. 🙂
Hello, a quick question that you may be able to answer: Why are winglets not also used? Surely there must be a pressure difference at the tip of the sail, analogous to airplane wings, which leads to vortices and thus an increase in drag Thank you in advance and please stay safe.
@@minime453 maybe, but you still need to see *where* those square meters are and also that taking off at a lower speed was critical in the last AC, let's see in this one
On the fat mainsheet exit... as long as they keep a sharp Kammback trailing edge in that region then the Karman vortex street turbulence will be minimized.
Yes, it's certainly not a complete disaster, but also not 'ideal' and blending the Kammback with the traditional sharp aerofoil trailing edge above can be tricky where you have soft sails
Great video! When you say Mainsheet, do you mean the control that pulls the leech straight down? I know some folks call that the sheet, and the side to side motion the traveller. As a dinghy sailor, I always think of the mainsheet as being the most important control, and the thing that makes the sail go in and out, as in sheeting in...or out... so, I would call the side to side motion of the clew sheet, and the vertical motion vang Thoughts?
looking at these large mainsheet cylinders I am wondering why these are not remotely mounted in the side hulls where there is more space and run through a 2:1 purchase onto the traveler. Then they would only need the width of the block between the the two sail skin cylinders?
Hello Mozzy, I am new to your "channel" but find it very interesting. Question: Is there any chance that the space between the two sail "membranes" could be used to house something else, for example a sort of braking system (parachute) that one could use to slow down and accelerate the boat (for starts, prioritoes etc.)?
They are limited on what can be put between the skins. In the bottom 1.5m they can put whatever they want, so control the skins. Then at the they need to carry a supplied buoyancy bag which stops the boat inverting if they capsize
At some point, all the resources put into making the main sail as efficient as possible will exceed the resources needed to for a wing. Are the teams approaching that point?
I am just wondering why. the hydraulics are not mounted on a plate fixed to an 'arm' (boom?) that fixes the relationship between the rotating mast and the traveller. In that way the three hydraulic rams can work on lines taken aft to the 'traveller' and up to the sail. This would allow the aft deck section to be 'shallow' and fit the rams under the deck where there is space regardless of the design. Are the traveller and rotating mast permitted to be fixed in their relative positions ?? Interesting topic is it not?
I strongly believe they can and in fact that is what prada had. I just suspect the added structure to take is around the 90 degree bend is too punitive in weight.
any reason that mast rotation cant be lines that then go underdeck to hydros ? or at least put hydros in own covers if you leave them on deck ... i'm guessing that rotation arm cant go below mast foot in rules
The main reason for lowering the deck is to reduce the overall frontal area of the boat because drag is the area squared. Small gains have a big effect. Add the additional sail area at the bottom and the dis-benefits of appendages sticking out melt away.
7:28... You need to do more reseach into aerodynamics. That fat clew is open, so works even better than a kamm-tail, and the net wind resistence as a result is zero. Kamm-tails are better than long tails, since there is no surace drag, and open kamm-tails are better than blunt kamm-tails as there's no physical sruface for the turbulence to attach to. Like I said... Do more research.
and yet, a year later, all the teams have followed the approach of moving the main sheet ram hardware down and the skin closer together. And Team New Zealand have gone a step further to remove all hardware. So, you may want to do more research
I have lost so much interest in the Americas Cup. There are a couple reasons I’m sure. I really disliked the multi hulls, it was too sterile. While the boats were fast, the actual racing was mind numbing boring. The new boats look like those frogs that run on top of the water. I think the technology has overtaken the roll and imperfections of the crew. I think the TP 52 racing is the best in the world today.
The penalty for truncating a wing is low, see kammback in automotive design ie shape of most hybrids/prius/tesla. Better to have a lower hull frontal area and get the mainsail longer and lower.
Agreed, but if the trailing edge is fatter than what is ahead of it, then that is bad. The skins are closer together at the leech immediately above, so you have a transition in trailing edge thickness to manage there and so in the section shapes above them. ETNZ made a lot of effort just before the cup match to taper that trailing edge, suggesting they weren't completely satisfied
@@MozzySails Agreed re thickening at the leech being bad (its a compromise etc) and the transition above the clew. Certainly ENTZ did work hard to reduce the size/profile of the clew mechanism. Also, what they may use for testing can be larger than any race system i.e. figure out the loads you needs to accommodate, wider range of movement in the test boat and then build a much reduced/miniaturised race version. Also, when would the stall be worst? At high cambers for takeoff..when most of the lift would be coming from the top of the rig in more apparent wind? Has anyone talked about how the whole hull becomes a wing with the Entz design (and luna rossa's?)_ i.e. some of the lift of the boat comes from the hull in profile? the crew cockpits acting as endplates i.e. in the opposite way to a 70s F1 ground effect car, with the lift supporting the boat.
There's a definite reduction in frontal area. Sometimes more frontal area is better _if_ the entire shape is superior from an aerodynamics perspective by delaying flow separation of the boundary layer. It depends on the overall design but generally speaking, the less frontal area the better.
The boom saga continues… love having mozzy back on my UA-cam recommended!!
So FREAKING glad you're back. You were the best thing about AC36 ...
I'm especially enjoying your new bionic arm at 5:50
That is quite hilarious editing on my behalf! 😅
@@MozzySails I thought so too, I just happened to pause at that moment and see it that way!
I laughed out loud!
Lovely, great chat, Mozzy is back to trends!
Love the tech chat, thanks for great videos!
I was sooo confused by the first image showing the cylinders sitting in the green cradle on deck. I'm like, "how TF does that act on the sail?!" It wasn't until 6:00 when we got to see all that gack in situ that the penny dropped! These boats are so damn cool. Thanks for the Video Mozz!
I'm pleased to have shed some light for you
I'm still wondering how the attachment to the track works, since, without a boom, there must be a lot of forward pull from the sail tension on the track.
@@charlestoast4051 Sure. It's not super creative sail control tech, but how they've set up the "traveller car" to resist the tension ripping it off the deck and still be free to move side to side would be an informative bit of mechanical design to see!
@@nickgoodall578 I would assume that it doesn't move freely but is moved with hydraulics. In which case just about any reasonably closely curved track would do (and I think they have calculated it down to 0.1mm, not just thrown some random track in 😉).
super interesting detailed reading of the pictures! looking forwrad to next few monthsof cup preparation now
It's going to be a good cup!
Good to have the Cup and your analysis back in the video feed
Good to have Mozzy Sails back on track. I love that tech chat. Go on!
Still so happy this is back
Great to have you back and loving the intel. Going to make this cup so much more engaging. Congrats on your rs800 and endeavour win too!
Thanks David! I've been I credibly fortunate to do as much sailing this year as I have and the Endeavour was a huge cherry on top. Proper boyhood dream come true!
Another great analysis
That edeting is so amazing! Thanks so much man!
Welcome back Mozzy
Love your insight! Thanks Mozzy.
My pleasure!
Scatchamagowza!!
Mozzy is back 🥰
Bring on the RECON 🕵🏼♀️
The cheap and simple way to achieve this and transfer the concept to cruising boats is to have a boom, but a foil curved boom which rotates from the boom hinge point in between the two sail foil skins and where the rotation angle automatically sets the tension as the rotation increases from side to side. The mast should also be mounted on a slightly conical slewing ring plate which directly transfers the loads to the hull on either side (slewing rings are the essential part of excavators that allow them to handle the extreme loads that diggers develop).
I find the Hull Shape intriguing. The genesis of this design style is not at all new. See the Shannon ShoalSailor (2004). But the real fore runner of all of these concepts was a design called the Aero Hydrofoil from the 1960’s.
I wonder how long it will be before someone attempts a mast head winglet to reduce pressure spill at the head of the sail?
I like to remind all of the super sailors that one of the most successful racing yachts was a Ferro Cement yacht, Helsal, which in 1973 achieved the trifecta of line honors, a time record, and winning on corrected time in the Sydney to Hobart Race. A trifecta the held for 35 years. The “Flying Footpath”.
I suspect the separation at the clew is unlikely to be as detrimental as you think due to a couple of reasons (see video 9:13): 1) the air in this area is likely to be turbulent flow and 2) lowering the deck lower moves the problem zone on the sail down further reducing the impact. I'm not sure whether the two skins on the sails are allowed to be connected but you would think if that was allowed, there would be some sort of internal skin to zip the sails together in this area. I'm also surprised the mainsheet ram is not rotated 180 degrees as the arm is much thinner than the ram body, this would also lower the weight in the boat. Thanks for the interesting vid and discussion.
I think they are allowed to be connected because I saw the teams connecting and separating the two halves of the mainsails.
Boom less low deck surely, come on INEOS get with the programme. Mozzy sails my guilty pleasure returns ⛵💨
9:22 as an aero engineer, I would call that "wing bit" a control horn. That's what we call similar fittings on control surfaces like elevators and ailerons
Or crank, maybe, to use a more general term
Great studio improvements! Nice intro and outro too. The bit in the middle? ... it's really good too.
Thanks Doug!
The discussion of the "thickness" of the hull is interesting.
Parasitic drag increases by the square of the airspeed, or I think apparent windspeed in this case. So the low deck, less frontal area, hull would be better for reducing drag. The interesting thing is that hull itself has to be acting as a wing to help the boat fly. I suspect there is a tradeoff between having a hull that is shallow with low drag and therefore does not produce much lift vs. one that is thicker with more drag but helps the boat to fly. The complexity is pretty mind boggling.
bopping intro
Best source in the last AC, best source for the next AC 🙂
a bit off topic but would it be possible for you to compare what the advantages and disadvantages of the wing sail used in previous cups compared to the double skin sails used now?
That would be interesting, we'll look at it at some point. There's a long time until Barcelona and plenty of sailing tech to discuss!
I'd be interested in this as SailGP are using wings
The solid wing sails are pretty fragile and if you recall the initial thinking with these new AC foiling monohulls was that they were likely to capsize, hence the original aim to be self righting. So if you are going to capsize you don't want to shred your wing. The performance isn't quite at the same level but it's certainly better than a single sail.
@@sailtastic Yes, and there's also the weight factor. The AC75 mainsails are much lighter without need of the complex mechanical parts of the solid sails. If the AC75 is more prone to capsizing, the possible effect on the center of gravity was definitely a consideration.
@@jamesaron1967 and @sailtastic Many thanks to you both. Love this channel.
Fascinating discussion. One has to assume that trades between 1 - larger but smoother faired upwind frontal area and smaller sail area down low, versus 2 - smaller faired frontal area (but more turbulent with beam protrusions) and lower sail center-of-effort were made. Dragging these big ugly high skin area hull shapes through the air must really eat up the available power from the sails.
In the previous Cup we ran a VPP model (quite crude) and the foils produced the overwhelming majority of the drag. That's not to say a few % can't be made from aero drag
Amazing content! Glad you are back at it, keep up the great work. I wonder even if these are the ac40 test boats, if you are willing to do a hull comparison between the teams...very different designs out there!
It looks like more teams will be emulating some of the key design features of Te Rehutai with sound reason. Luna Rosa has adopted the dropped deck feature and it's a good guess Alinghi will follow suit now that they've gone boom-less. It will be great to see Te Aihe optimized with further development. I always liked the lines of this yacht.
The fat clew might not be as bad from an aerodynamics perspective as it appears. Those familiar with aerodynamics theory will be aware of a Kamm tail. It's a truncated airfoil that generates controlled turbulence in applications where a full length airfoil is either impractical or restricted by regulation. It's heavily used in modern pro cycling because the UCI has strict rules governing aerodynamics of components. It's also advantageous in certain yaw angles, which may or may not apply to the speeds the AC75 is capable of. This subject is very complex and I'm by no means an expert in fluid dynamics, but wondering how much of an actual detriment the fat clew is aerodynamically?
I was thinking about the clew thickness. It doesn't strike me as aerodynamically optimal. Would it be possible to relocate the ram under the deck near the mast? If you fix one end to the traveller and then use a block on the clew and in the mast to route a (presumably low stretch) control line?
As others have commented, it's good to see you back.
edit - on reflection, using a crank located between the clew plates might allow the line to be routed directly down to the deck which would prevent the line messing up the upwind sail surface. You could then run the line through a below-deck block toward the mast foot. On further reflection, the entire traveler system could be rigged backwards with the running end connected to the clew and a below deck block running the main sheet to the foot of the mast where you could install the ram.
Very interesting, would be great if you could do a "where are all the teams at, at the moment summary"
In early November we'll be posting our first monthly recon teams where we'll present tech situation and sailing time for each team. Aim is to do these monthly right up to AC37
I should have added that the fore runner of the Shannon Shoal Sailor was the Dutch Sailing Barge, and the reason why the Dutch were so far ahead as ship builders was because of the Dutch Timber cutting Windmills. Technology wins every time, and complementary technology is even better.
I sailed a Nacra 5.8 Catamaran for years with a boomless main that swept the deck with an adjustable clew, way more sail trim adjustments than my Inter20 with a boom
welcome back!
Thanks 4 sharing
Thanks for watching!
If most are doing it I assume that extra drag and fat clew are worth the benefits - lowered sail/deck/ centreOE etc.
Never will know but I wonder if TNZ held back development last cycle and they had cleaner and more efficient set up. Silly question, is drag more relevant up or down wind in this class?
Thanks for the insights
I though that was an obvious question but then I threw some ballpark numbers in an apparent wind speed calculator... 45 degree upwind and 135 degree downwind angle with 20kn upwind speed and 50kn downwind speed in 20kn wind... The difference is only 1.5kn.
If you have time to look up actual wind speed, boat speed and direction data and calculate more accurate numbers, let me know what you come up with because this is a bit interesting.
@@AnttiBrax thanks for your response, that seems like a negligible difference. I think I’d be out of my depth at a quick rate if I started throwing numbers about. But I am keen to learn, albeit at a high level/overview. Have a great weekend
General pattern is that boat designs become more similar. Probably your discussions said that lowering the sail down as low as possible generates notable net gains.
How about a bendy boom. i.e. rigid vertically but bendy laterally. Obviously I no nothing having only sailed a Mirror dingy but loving all the amazing design problems. The Americas Cup has everything! Will be glued to your channel for the rest of the years, a big thank you.
I like the “in clew” sheeting system, but don’t like the ram and gubbins to control the mast which along with the fatter clew does cause aerodynamic problems. Having a slimmer deck also allows more sail area, but I wonder if it’s not better to have a completely smooth aerodynamic laminar flow deck shape to turn the whole boat body into one big uncluttered wing with less hindrance to the upper, low pressure surface?
Great analysis! I'm wondering if there's an aerodynamic advantage for Alinghi, Luna Rossa etc in having a lowered deck? Apart from the wing "thing" by the mast rotation this probably leads to less frontal surface to cause head-on drag, don't you think?
Is it that a lowered deck is more about being a quicker and easier maintenance access point for the teams than a major performance benefit at this point during testing? One thought on the Clew being wider as a non-issue, if it was viewed from a Kamm tail aerodynamic perspective?
Good insights Mozzie. I am thinking that if that gizmo is on AC40s (which are identical I believe) then it is unlikely to be on the AC75. I further suspect the NZ yacht will be totally different from last regatta. In particular, it won't have a jib as apart from the start it actually slows the yacht down at high speed and it will focus on high speed ahead of everything else as it will really be a plane. All this should be the trigger to get back to real yachts. 🙂
Ok p
Hello, a quick question that you may be able to answer: Why are winglets not also used? Surely there must be a pressure difference at the tip of the sail, analogous to airplane wings, which leads to vortices and thus an increase in drag Thank you in advance and please stay safe.
The lower deck also allows for more main sail area, I think they’ll be crazy not to take that free extra horse power
I believe in the previous cup TNZ had roughly 3 square meters extra sail
@@minime453 maybe, but you still need to see *where* those square meters are and also that taking off at a lower speed was critical in the last AC, let's see in this one
I Think every team will go for the lower ,as you can see it from the last AC36 ETNZ was just quicker than everyone else
On the fat mainsheet exit... as long as they keep a sharp Kammback trailing edge in that region then the Karman vortex street turbulence will be minimized.
Yes, it's certainly not a complete disaster, but also not 'ideal' and blending the Kammback with the traditional sharp aerofoil trailing edge above can be tricky where you have soft sails
Great video! When you say Mainsheet, do you mean the control that pulls the leech straight down? I know some folks call that the sheet, and the side to side motion the traveller. As a dinghy sailor, I always think of the mainsheet as being the most important control, and the thing that makes the sail go in and out, as in sheeting in...or out... so, I would call the side to side motion of the clew sheet, and the vertical motion vang Thoughts?
looking at these large mainsheet cylinders I am wondering why these are not remotely mounted in the side hulls where there is more space and run through a 2:1 purchase onto the traveler. Then they would only need the width of the block between the the two sail skin cylinders?
Hello Mozzy, I am new to your "channel" but find it very interesting. Question: Is there any chance that the space between the two sail "membranes" could be used to house something else, for example a sort of braking system (parachute) that one could use to slow down and accelerate the boat (for starts, prioritoes etc.)?
They are limited on what can be put between the skins. In the bottom 1.5m they can put whatever they want, so control the skins. Then at the they need to carry a supplied buoyancy bag which stops the boat inverting if they capsize
At some point, all the resources put into making the main sail as efficient as possible will exceed the resources needed to for a wing. Are the teams approaching that point?
I am just wondering why. the hydraulics are not mounted on a plate fixed to an 'arm' (boom?) that fixes the relationship between the rotating mast and the traveller. In that way the three hydraulic rams can work on lines taken aft to the 'traveller' and up to the sail. This would allow the aft deck section to be 'shallow' and fit the rams under the deck where there is space regardless of the design. Are the traveller and rotating mast permitted to be fixed in their relative positions ?? Interesting topic is it not?
I strongly believe they can and in fact that is what prada had. I just suspect the added structure to take is around the 90 degree bend is too punitive in weight.
any reason that mast rotation cant be lines that then go underdeck to hydros ? or at least put hydros in own covers if you leave them on deck ... i'm guessing that rotation arm cant go below mast foot in rules
Did you get a new camera? Very nice video quality....so happy to see your video again 👍
I did! I think it looks better
I think with engineering iterations they will be able to narrow the three main components and get the clew thinner..
Gret post
The main reason for lowering the deck is to reduce the overall frontal area of the boat because drag is the area squared. Small gains have a big effect. Add the additional sail area at the bottom and the dis-benefits of appendages sticking out melt away.
Lowered deck seems to give the hull nice horizontal wing shape. Propably greating bigger pressure differential above and below the hull.
drag is a product of the area times the speed squared......
@@charlestoast4051 Yes, quite right. I knew it was something like that.
7:28... You need to do more reseach into aerodynamics. That fat clew is open, so works even better than a kamm-tail, and the net wind resistence as a result is zero.
Kamm-tails are better than long tails, since there is no surace drag, and open kamm-tails are better than blunt kamm-tails as there's no physical sruface for the turbulence to attach to.
Like I said... Do more research.
and yet, a year later, all the teams have followed the approach of moving the main sheet ram hardware down and the skin closer together. And Team New Zealand have gone a step further to remove all hardware. So, you may want to do more research
In 5y it's going to be a sail and a wing
Giant surfboard
I have lost so much interest in the Americas Cup. There are a couple reasons I’m sure. I really disliked the multi hulls, it was too sterile. While the boats were fast, the actual racing was mind numbing boring. The new boats look like those frogs that run on top of the water. I think the technology has overtaken the roll and imperfections of the crew. I think the TP 52 racing is the best in the world today.
The penalty for truncating a wing is low, see kammback in automotive design ie shape of most hybrids/prius/tesla. Better to have a lower hull frontal area and get the mainsail longer and lower.
Agreed, but if the trailing edge is fatter than what is ahead of it, then that is bad. The skins are closer together at the leech immediately above, so you have a transition in trailing edge thickness to manage there and so in the section shapes above them.
ETNZ made a lot of effort just before the cup match to taper that trailing edge, suggesting they weren't completely satisfied
@@MozzySails Agreed re thickening at the leech being bad (its a compromise etc) and the transition above the clew. Certainly ENTZ did work hard to reduce the size/profile of the clew mechanism. Also, what they may use for testing can be larger than any race system i.e. figure out the loads you needs to accommodate, wider range of movement in the test boat and then build a much reduced/miniaturised race version. Also, when would the stall be worst? At high cambers for takeoff..when most of the lift would be coming from the top of the rig in more apparent wind?
Has anyone talked about how the whole hull becomes a wing with the Entz design (and luna rossa's?)_ i.e. some of the lift of the boat comes from the hull in profile? the crew cockpits acting as endplates i.e. in the opposite way to a 70s F1 ground effect car, with the lift supporting the boat.
I suspect the low deck is more aero efficient than high deck. Therefore I predict low deck
There's a definite reduction in frontal area. Sometimes more frontal area is better _if_ the entire shape is superior from an aerodynamics perspective by delaying flow separation of the boundary layer. It depends on the overall design but generally speaking, the less frontal area the better.
I want one for my Holder12 monohull. No? Ok, whatever. 😆
What happened to keep it simple
That was the Laser dinghy. This video is about the AC75 class. Easy confusion. Happens to everyone. Cheers.
Everyone will copy the ETNZ cup winner. ETNZ will make another jump in design philosophy and leave everyone in their dust again 😶💨
Curious to see what ETNZ will come up with their new AC75.
"Te Aihe" is pronounced "Tee Eye-He"
Teh eye heh
The "e" in "Te" is a short "e" like in "Ted" rather than a long "ee" like in T-Shirt.
Te => The
Aihe => Dolphin
Please say either, not eether.
Cut.
Tommy Mozzie is English. His people invented the language!
@@paulgush Exactly
It's a self-referential word, in that you can pronounce it either as either or either.
Okay then Kiere and not Keere right?