USA Vs NZL
- Thread starter Don Guillette
- Start date
- Status
yes! I wish we could get good view or schematics of the foil and tail piece. And I'd like to see the relative positions in different trim modes. But we've noted a very pronounced kink between the two. I think the wings will change some ideas about sail trim. I just haven't been able to get a handle on it. The story line has been the foils not the wings.
More observations ....
I'm sure many don't appreciate negative comments, but, what's a discussion without a little dissent?
For most people, watching a sailboat race in the old days, was not only boring, but very confusing as well. Without the graphics, it was next to impossible to understand who was in front and exactly what were they doing? And then there were all the sail changes and people on deck spinning all these cranks, and for what reason? It was never explained. At least on the downwind runs, it made some sense that they had big sails like a balloon, they headed more or less straight for the downwind marks and it just made more sense that going downwind is faster.
I've been trying to think of the physics, but I can't seem to explain to myself exactly why getting up on the foils and going 40 knots is so much easier on the downwind reaches than it is on the upwind leg. We know that the apparent wind is always ahead of the mast because the true wind is about 20 knots less than the boat speed when flying downwind. So if the apparent wind is so much higher on the up-wind leg, then why aren't the boat speeds faster when going upwind? Yet getting up on foil going upwind is more difficult and the speed is decidedly lower. That has been puzzling me. Intuitively, it makes more sense that boats are faster on reaches than close-hauled, but with the new dynamics where the apparent wind is always forward, why is this so?
Also, I couldn't help wondering what is all the cranking about? I mean the sails barely even move, due to the nature of apparent wind. It was really fun watching these guys racing from one side of the boat to the other, and I'm not ever going to question their athleticism, but I can't quite understand why SO much cranking ALL the time, even when they seem to be going in a straight line. We all understand about course corrections and wind shifts, but what's the deal. Do they have to crank 5 revolutions to draw in a micro-mm of line? Announcers could do a better job at explaining why these guys have to do SO MUCH work because it isn't really obvious. Just saying that the loads are so high doesn't go far enough to describe what they are actually doing. The sails or wings are always close-hauled, there are no sail changes (except maybe between races for the tiny headsail), so what is all the cranking about? It also seems like all the cranking is always in the same direction, so doesn't there reach a point where they are over cranked? It just seems like they are incessantly spinning those things and it's not clear why.
When a linebacker puts in so much effort to chase a guy clear across the field before he gets across the line of scrimmage, the reason for his effort is obvious. These guys in the pit are obviously putting in the same physical effort, but it just isn't apparent why. It makes it so much more difficult for the fan to appreciate what is going on.
I've got more, but I have to leave for now. I'll get back later!
I'm sure many don't appreciate negative comments, but, what's a discussion without a little dissent?
For most people, watching a sailboat race in the old days, was not only boring, but very confusing as well. Without the graphics, it was next to impossible to understand who was in front and exactly what were they doing? And then there were all the sail changes and people on deck spinning all these cranks, and for what reason? It was never explained. At least on the downwind runs, it made some sense that they had big sails like a balloon, they headed more or less straight for the downwind marks and it just made more sense that going downwind is faster.
I've been trying to think of the physics, but I can't seem to explain to myself exactly why getting up on the foils and going 40 knots is so much easier on the downwind reaches than it is on the upwind leg. We know that the apparent wind is always ahead of the mast because the true wind is about 20 knots less than the boat speed when flying downwind. So if the apparent wind is so much higher on the up-wind leg, then why aren't the boat speeds faster when going upwind? Yet getting up on foil going upwind is more difficult and the speed is decidedly lower. That has been puzzling me. Intuitively, it makes more sense that boats are faster on reaches than close-hauled, but with the new dynamics where the apparent wind is always forward, why is this so?
Also, I couldn't help wondering what is all the cranking about? I mean the sails barely even move, due to the nature of apparent wind. It was really fun watching these guys racing from one side of the boat to the other, and I'm not ever going to question their athleticism, but I can't quite understand why SO much cranking ALL the time, even when they seem to be going in a straight line. We all understand about course corrections and wind shifts, but what's the deal. Do they have to crank 5 revolutions to draw in a micro-mm of line? Announcers could do a better job at explaining why these guys have to do SO MUCH work because it isn't really obvious. Just saying that the loads are so high doesn't go far enough to describe what they are actually doing. The sails or wings are always close-hauled, there are no sail changes (except maybe between races for the tiny headsail), so what is all the cranking about? It also seems like all the cranking is always in the same direction, so doesn't there reach a point where they are over cranked? It just seems like they are incessantly spinning those things and it's not clear why.
When a linebacker puts in so much effort to chase a guy clear across the field before he gets across the line of scrimmage, the reason for his effort is obvious. These guys in the pit are obviously putting in the same physical effort, but it just isn't apparent why. It makes it so much more difficult for the fan to appreciate what is going on.
I've got more, but I have to leave for now. I'll get back later!
Re: More observations ....
Scott, I only saw a couple of the LV Cup races, but the announcers said the cranking was for the hydraulic system(s) in the boats.
Scott, I only saw a couple of the LV Cup races, but the announcers said the cranking was for the hydraulic system(s) in the boats.
scott, the trim is very slight but they are working large loads like you said on a crew with almost total synergy, they're live trimming (out, in, out, in, puff, out, in) constantly...watch the fairlead block coming off the winch drum from the pit guy doing the trimming on the beats during the last race, they'll grind a little then brrrr, the trimmer lets out what seems to be the same amount they just trimmed in, they're sailing these 72 footers more like a nacra than a mega-yacht.
Because the wind is always forward of the beam, but the angle does change.
Remember that the lift force produced by the sail is at right angles to the apparent wind. So as the apparent wind shifts aft, there is more of the lift pushing the boat forward and less pushing the boat sideways. More forward force means the boat goes faster.
( also the less sideways force means that the daggerboards don't produce as much drag, so it's that much faster ).
Toad
They're cranking both the winch drums, and the hydraulic system. Hydraulics are used for the wing, and for the foils (pitch, cant, and raising/lowering). Since stored energy is not permitted, other than battery power for valve actuation (including servo valves in the wing, I believe), hydraulic accumulators are not allowed, so they're grinding any time pressurized flow to the foils and the wing is needed - no storing it for future use. Plus they grind the headsail drum mechanically, which I've noticed is sometimes cranked from the top by the trimmer, though that may be under no-load conditions.
to respond to the question of how they go so fast down wind and what would happen to a boat doing 40kts if the wind suddenly went calm its a factor of pressure and vector. start with the boat on a beam reach in 20kts wind, boat at 20kts, at this point the boat will be abeam of the true wind and because of the vector will be experiencing an apparent wind at 45 degrees to the bow. in the case of the ac72 you are now abeam of the true wind and close hauled on the foils, now as you bear off to go "down wind" you continue to accelerate and add apparent wind and hold a balance with the pressure of the wind direction to keep the apparent wind at sufficient velocity and angle (vector) to power the rig, as you do this and seek your balance the boat accelerates bearing off while still having an apparent vector of 45 on the bow, at some point you will bear off further and the true wind will be so far behind the boat that you experience an apparent velocity lull, at this point you must drive back up until the apparent wind and the boat recover their equilibrium, this is why the ac72 has such a wide jybe angle. now if the boat is doing 40kts "down wind" in 20kts of breeze and the air suddenly calms to 0 the boat will experience an apparent in irons condition with 40kts hard on the bow and dropping as the boat slows. in effect the speed capability of the boat is a factor of how much pressure the true wind can put into the vector equation to keep the boat balanced down wind, higher wind speeds would let you drive deeper to a point but will quickly become out of hand for upwind return legs since the math starts going the other way, think about what the crews were experiencing when going to weather on the foils in 20kts of breeze and a boat speed of 30kts, aside from more boat speed closing the apparent wind in on your nose causing you to bear off to keep drive going the apparent wind speeds on deck in some of the final ac races had to be approaching tropical storm levels, yes in theory these boats should be able to reach down wind in 40kts of breeze doing 60kts of boat speed but at that theoretical point the boat will be unable to go upwind at all.
Making sense ...
basically, it is the apparent wind angle closing in on the nose that is limiting boat speed on the upwind leg despite the increase of apparent wind. As always, VMG is the balancing act, and it just so happens that it is going to be somewhat slower upwind than downwind. Obviously, there is a fine line where getting the boat up on foils going upwind is possible and when it is achieved it dramatically affects the dynamics of the race.
I'll throw another few thoughts out there ...
The starts are certainly interesting, but I get the feeling that with the format they are using where the start is a beam reach drag race to the first mark, it would be more interesting if there were no windward - leeward rules. In a few of the races, it seemed almost silly the way the leeward boat used the rule to slow down the race. I think it would be more interesting if the boats closed in on the first mark at different angles at high speed to make the next leg more challenging. The way the races tended to go, the race to the mark was only interesting to see who would get there first, then the downwind leg left nothing to the imagination because there wasn't going to be any lead change there.
Only the upwind legs made the race a competition. So why only one upwind leg? The only lead change I saw on a downwind leg was when both boats essentially arrived at the upwind marks at the same time (split) and the US made a tactical error to lose the lead.
I know it is heretical to even think about changing the leeward - windward rules, and the stbd - port rules, (I'm SO ashamed for even thinking it!) but maybe they can be looked at critically to make these high speed races less monotonous once one boat gains the advantage over the other. The boat speed aspect certainly increased the value of the upwind legs, yet each race only features one upwind leg. I think there should be two upwind legs.
Also, match racing might be more interesting if there were a 3rd boat in the match. That way the lead boat can't focus all their attention on closing out just one boat. The third boat would create a whole new level of excitement as a wild card.
I think these races were very exciting but couldn't help thinking that so much of the action is essentially meaningless when there is virtually no chance of a lead change on so many segments of the race. 90% of the time the race was determined by the boat rounding the windward mark first. There wasn't much point to the remainder of the race, except the final reach was more-or-less a victory lap for the cheering crowd (which was way cool, I'll admit).
basically, it is the apparent wind angle closing in on the nose that is limiting boat speed on the upwind leg despite the increase of apparent wind. As always, VMG is the balancing act, and it just so happens that it is going to be somewhat slower upwind than downwind. Obviously, there is a fine line where getting the boat up on foils going upwind is possible and when it is achieved it dramatically affects the dynamics of the race.
I'll throw another few thoughts out there ...
The starts are certainly interesting, but I get the feeling that with the format they are using where the start is a beam reach drag race to the first mark, it would be more interesting if there were no windward - leeward rules. In a few of the races, it seemed almost silly the way the leeward boat used the rule to slow down the race. I think it would be more interesting if the boats closed in on the first mark at different angles at high speed to make the next leg more challenging. The way the races tended to go, the race to the mark was only interesting to see who would get there first, then the downwind leg left nothing to the imagination because there wasn't going to be any lead change there.
Only the upwind legs made the race a competition. So why only one upwind leg? The only lead change I saw on a downwind leg was when both boats essentially arrived at the upwind marks at the same time (split) and the US made a tactical error to lose the lead.
I know it is heretical to even think about changing the leeward - windward rules, and the stbd - port rules, (I'm SO ashamed for even thinking it!
) but maybe they can be looked at critically to make these high speed races less monotonous once one boat gains the advantage over the other. The boat speed aspect certainly increased the value of the upwind legs, yet each race only features one upwind leg. I think there should be two upwind legs.Also, match racing might be more interesting if there were a 3rd boat in the match. That way the lead boat can't focus all their attention on closing out just one boat. The third boat would create a whole new level of excitement as a wild card.
I think these races were very exciting but couldn't help thinking that so much of the action is essentially meaningless when there is virtually no chance of a lead change on so many segments of the race. 90% of the time the race was determined by the boat rounding the windward mark first. There wasn't much point to the remainder of the race, except the final reach was more-or-less a victory lap for the cheering crowd (which was way cool, I'll admit).
Scott,
From some of the talk early in the series it sounded like getting the boat onto the foils upwind wasn't really the hard part, but that the challenge was not giving up too much leeway when doing so. It sounded to me like raising that leeward hull would kill too much of sideways drag and kill the VMG. Going downwind the leeway is actually a good thing as it's toward the mark. Not sure what Oracle did to maintain enough lift when foiling late in the series, but it could be that they just decided that their "low fast mode" was fast enough to give a better VMG even with some extra leeway.
As for the rules during the first reach - I'm not sure removing the leeward/windward rule would help much. You need to have some favored boat in that situation to avoid collisions, and if the windward boat were favored then the pre-start would just be a race to get to the upwind side of the line to run over the wind of the other. I liked the dynamic during that leg of the windward boat using its slightly faster reach angle to try to break any overlap and round first. If they did, they're rewarded with a head start on leg 2. If they weren't fast enough to break the overlap then I think it's fair that the leeward boat block them out to kill their speed.
I agree it would've been nice if there were more downwind lead changes, but I'm not sure how that could be achieved sailing to an apparent wind without spinnakers. Luckily there were quite a few upwind passes. Given that, maybe an extra upwind leg should be added before the final reach. That would also have the benefit of bringing the finish closer to the start so spectators on shore could have a better view of both.
From some of the talk early in the series it sounded like getting the boat onto the foils upwind wasn't really the hard part, but that the challenge was not giving up too much leeway when doing so. It sounded to me like raising that leeward hull would kill too much of sideways drag and kill the VMG. Going downwind the leeway is actually a good thing as it's toward the mark. Not sure what Oracle did to maintain enough lift when foiling late in the series, but it could be that they just decided that their "low fast mode" was fast enough to give a better VMG even with some extra leeway.
As for the rules during the first reach - I'm not sure removing the leeward/windward rule would help much. You need to have some favored boat in that situation to avoid collisions, and if the windward boat were favored then the pre-start would just be a race to get to the upwind side of the line to run over the wind of the other. I liked the dynamic during that leg of the windward boat using its slightly faster reach angle to try to break any overlap and round first. If they did, they're rewarded with a head start on leg 2. If they weren't fast enough to break the overlap then I think it's fair that the leeward boat block them out to kill their speed.
I agree it would've been nice if there were more downwind lead changes, but I'm not sure how that could be achieved sailing to an apparent wind without spinnakers. Luckily there were quite a few upwind passes. Given that, maybe an extra upwind leg should be added before the final reach. That would also have the benefit of bringing the finish closer to the start so spectators on shore could have a better view of both.
I would think about making the first leg after the reaching mark being an upwind leg rather than a downwind leg.
I think that some bumping at the mark might improve the sport. The bumping in NASCAR races certainly add an element that fans enjoy. These guys have proven that they have money to burn so what should we care if the boats get scarred up a bit. I wouldn't make either side favored. Let it be about jockeying for position. There are no favored positions in horse racing when coming to the first turn. The riders have to sort that out for themselves.
The windward-leeward rule is a relic from the days when yacht owners needed to protect their gleaming yachts, and it certainly is valid when us amateurs want to get into the game. But in this match, let's hear what the reason for it is.
I'm thinking that the new boats with the dual steering pedestals will start adapting their pedestals to be oriented like these boats are ... with the wheels angled for a better view along the rail.
I think that some bumping at the mark might improve the sport. The bumping in NASCAR races certainly add an element that fans enjoy. These guys have proven that they have money to burn so what should we care if the boats get scarred up a bit. I wouldn't make either side favored. Let it be about jockeying for position. There are no favored positions in horse racing when coming to the first turn. The riders have to sort that out for themselves.
The windward-leeward rule is a relic from the days when yacht owners needed to protect their gleaming yachts, and it certainly is valid when us amateurs want to get into the game. But in this match, let's hear what the reason for it is.
I'm thinking that the new boats with the dual steering pedestals will start adapting their pedestals to be oriented like these boats are ... with the wheels angled for a better view along the rail.
More about grinding ...
So these guys are doing all that spinning and grinding to building the oil pressure in the hydraulics? Yikes! no wonder the announcers feel like there is no value in explaining that aspect of sailboat racing in detail. How mundane ... it's too bad there isn't something more exciting for them to do while putting out so much effort. To make it worse, there was one guy (I couldn't tell who, but I think it was on the NZ boat) who sounded like a woman in labor when he was grinding. Something has to be done to make these guys in the pits look and sound like they are doing something macho! Pressurizing the hydraulic fluid?!?! Come'on Man! Isn't there a 100 mph fastball that you can knock out of the park?
(Just having a little bit of fun pointing out some of the absurdity of sailboat racing)
So these guys are doing all that spinning and grinding to building the oil pressure in the hydraulics? Yikes! no wonder the announcers feel like there is no value in explaining that aspect of sailboat racing in detail. How mundane ... it's too bad there isn't something more exciting for them to do while putting out so much effort. To make it worse, there was one guy (I couldn't tell who, but I think it was on the NZ boat) who sounded like a woman in labor when he was grinding. Something has to be done to make these guys in the pits look and sound like they are doing something macho!
Pressurizing the hydraulic fluid?!?! Come'on Man! Isn't there a 100 mph fastball that you can knock out of the park? (Just having a little bit of fun pointing out some of the absurdity of sailboat racing
)- Status