America's Cup- Am I alone?

[Rum_Pirate]

Interesting that when Emirates came off foils LR made a 2,000 m lead.
Then LR came off foils, Emirates recovered that distance and then went on to will by almost 2,000m.

Question: Why when the boats are off the foils, why don't they lower the second foil and use both of them to get extra lift to get back up and foiling. Once foiling they can then lift the windward foil.

 

[Kukri]

Interesting that when Emirates came off foils LR made a 2,000 m lead.
Then LR came off foils, Emirates recovered that distance and then went on to will by almost 2,000m.

Question: Why when the boats are off the foils, why don't they lower the second foil and use both of them to get extra lift to get back up and foiling. Once foiling they can then lift the windward foil.

I think it is because, when the boats are off their foils, they are much less stable, and they need the windward foil with its near one ton of lead out to windward to “sit the boat up”.

 

[Tomahawk]

When small mistakes have such catastrophic consequences it makes the racing into a lottery.

 

[bdh198]

LP got 3 penalties for going outside course. Not sure how they got to clear them.

Googled to see what I could find.

PENALTY RULE
If the umpires agree, you'll be given a penalty. In this America's Cup that means you have to put the brakes on. Slow down and slide back, until you're 50 metres behind your competitor, and wait until the umpires tell you you're good to accelerate again – and the match is in full motion once more.

Given that LR were off their foils and virtually dead in the water[not sure how they could slow down much more] and Emirates was screaming away it seems that the penalties counted for naught.

So, if they are already 50 meters behind their competitor, how do the umpires determine when the penalty is clear? Do they some how have demonstrate that they have slowed down (not racing to their full potential) for a particular period of time?

 

[flaming]

I think it is because, when the boats are off their foils, they are much less stable, and they need the windward foil with its near one ton of lead out to windward to “sit the boat up”.

As I understand it, this is basically it, but to expand a bit.

When the boats are foiling on 1 foil their pivot point is way out to leeward of the hull and the centre of mass. So the whole weight of the boat is righting moment. Plus of course the lift generated by the foil in the water is also righting moment. The available power is therefore "considerable" as the righting moment to counteract the sail plan is very much larger than you would get just by swinging a traditional keel, for example. It's much more similar to a trimaran, except that it also increases with speed.

However, when the boat is stationary or only moving very slowly through the water, the buoyancy is on the centreline, and the weight of the windward foil is the primary righting moment generator. As the speed increases the lift from the leeward foil becomes more significant and not only lifts the hull out of the water, reducing drag, but also provides a righting moment increase as this lift is coming from a point to leeward of the hull.

My understanding is that getting the boat to move faster, rather than adding extra lifting surface is the better way to get onto the foils earlier, and to do this they need more power from the rig, which of course they need to counter with righting moment. The good news for the crews is that it is a virtuous circle - the faster they go, the more righting moment they are producing (even well before lift off) and therefore the more power they can ask for from the trimmers. But in the initial phase they need the weight from the windward foil swung out to windward to use as "static" RM just to get them moving.
After all, if you just put both foils down and rely on their weight to act like a keel, then you have a keel weight of less than 2 Tonnes on a keel of 5m. The Maxi 72 class has a bulb weight of circa 8.5 Tonnes and a draft of 5.5m. So your available righting moment is small compared to a conventional boat, until you're moving.

What is interesting is that the teams have been describing the boats as "underpowered" for some time. My expectation for V2 of the rule for the next cup (assuming that we do go again in this class) is either bigger rigs (possibly with allowable mainsail area reduction for strong wind days) or reduced foil weight, or both. But probably increased rigs, as the reason they settled on the bulb weight was so that (in theory at least) the boats would self right after a capsize.

 

[Rum_Pirate]

So, if they are already 50 meters behind their competitor, how do the umpires determine when the penalty is clear? Do they some how have demonstrate that they have slowed down (not racing to their full potential) for a particular period of time?

I suspect it is done in the umpires 'control room' where GPS etc information is processed after being collected from the 'post' located on the stern of the yachts.

Also used to determine if they are outside the side boundaries.

 

[adwuk]

The racing today was much more interesting. The first race was a proper match race, and the second certainly had the entertainment factor! That said, ETNZ looks to be finding their form, and certainly had an extra gear today. My prediction is that it will be all over tomorrow morning. Let's see!

 

[Mistroma]

I suspect it is done in the umpires 'control room' where GPS etc information is processed after being collected from the 'post' located on the stern of the yachts.

Also used to determine if they are outside the side boundaries.

I'm pretty certain that the Italian boat had altered course and curved off in the wrong direction for a short while just before their penalty was lifted. They were foiling at that point would have had -ve VMG and that might be considered as reducing speed. I wondered if that explicit -ve VMG manoevre was used to signal reduction in speed and clear the penalty quickly.

They certainly would want to actually slow speed over the water downwind at that point in case they reverted to "floating pig" mode.

 

[bdh198]

Race 9 - without doubt the best day of racing so far (and that’s even with the second race being abandoned). It’s just a shame some of the earlier races weren’t more like that rather than a matter of who got the better start.

 

[Kukri]

Maybe it is not too soon to start wondering about the whereabouts of Sir James Ratcliffe or at any rate his designated Representative in New Zealand and the Commodore of the Royal New Zealand Yacht Squadron in a few hours’ time.

 

[flaming]

Maybe it is not too soon to start wondering about the whereabouts of Sir James Ratcliffe or at any rate his designated Representative in New Zealand and the Commodore of the Royal New Zealand Yacht Squadron in a few hours’ time.

Pedant mode... It would be the commodore of the RYS who issues the challenge. Of course he might ask Ratcliffe to deliver it for him....

 

[Kukri]

Pedant mode... It would be the commodore of the RYS who issues the challenge. Of course he might ask Ratcliffe to deliver it for him....

Quite right. Thank you!

 

[Kukri]

Ratcliffe may have thought better of the idea, of course.

 

[Resolution]

Ultimately seeing the best sailors race in equal one design equipment for sailors would be far more of an interesting contest - but as it stands AC is a different type of competition where the race is invariably won by the design department before the foils touch the water. There is only so much match racing you can do with a boat that is slower to tack/accelerate/points lower etc

Not wishing j80 any personal ill, but I am delighted that the extremely exciting races of the past two days have proved him so wrong. Full marks to all those behind this edition of the Auld Mug for coming up with such a radical formula. My wife and I are hoping that the Kiwis score the necessary 7th win, so that we can book up to go to Auckland for the next edition (which could be even more exciting) and tick NZ off our bucket list of places to visit and sail.

 

[JumbleDuck]

Pedant mode... It would be the commodore of the RYS who issues the challenge. Of course he might ask Ratcliffe to deliver it for him....

RYS now reported as challenger of record. Does that mean that the Italians came a bit too close for comfort?

 

[Kukri]

I think the deal was done before the final.

 

[flaming]

RYS now reported as challenger of record. Does that mean that the Italians came a bit too close for comfort?

CoR is very rarely about the racing, it's about who the clubs can "do business" with. Who is open to their vision for the next cup basically.

So if you want to run the next cup in 100 foot log canoes, for example, then you need to find a CoR who will agree. Otherwise they just turn around and say "90 foot on the waterline, see you in 9 months". Which is what it defaults to if the defender and the CoR cannot agree alternative rules.

 

[adwuk]

Some speculation of an event being run in Cowes in 2022 as well. Have to see if there is any substance to this in the coming days/weeks.

 

[Sailfree]

As I understand it, this is basically it, but to expand a bit.

When the boats are foiling on 1 foil their pivot point is way out to leeward of the hull and the centre of mass. So the whole weight of the boat is righting moment. Plus of course the lift generated by the foil in the water is also righting moment. The available power is therefore "considerable" as the righting moment to counteract the sail plan is very much larger than you would get just by swinging a traditional keel, for example. It's much more similar to a trimaran, except that it also increases with speed.

However, when the boat is stationary or only moving very slowly through the water, the buoyancy is on the centreline, and the weight of the windward foil is the primary righting moment generator. As the speed increases the lift from the leeward foil becomes more significant and not only lifts the hull out of the water, reducing drag, but also provides a righting moment increase as this lift is coming from a point to leeward of the hull.

My understanding is that getting the boat to move faster, rather than adding extra lifting surface is the better way to get onto the foils earlier, and to do this they need more power from the rig, which of course they need to counter with righting moment. The good news for the crews is that it is a virtuous circle - the faster they go, the more righting moment they are producing (even well before lift off) and therefore the more power they can ask for from the trimmers. But in the initial phase they need the weight from the windward foil swung out to windward to use as "static" RM just to get them moving.
After all, if you just put both foils down and rely on their weight to act like a keel, then you have a keel weight of less than 2 Tonnes on a keel of 5m. The Maxi 72 class has a bulb weight of circa 8.5 Tonnes and a draft of 5.5m. So your available righting moment is small compared to a conventional boat, until you're moving.

What is interesting is that the teams have been describing the boats as "underpowered" for some time. My expectation for V2 of the rule for the next cup (assuming that we do go again in this class) is either bigger rigs (possibly with allowable mainsail area reduction for strong wind days) or reduced foil weight, or both. But probably increased rigs, as the reason they settled on the bulb weight was so that (in theory at least) the boats would self right after a capsize.

How do they decide new rules for 37th AC?

Is it a unilateral decision by NZ? do changes have limitations?

I really enjoyed the races when boats swapped places but boring when boat over start line 1st just extends its lead over next 6 legs.

 

[flaming]

How do they decide new rules for 37th AC?

Is it a unilateral decision by NZ? do changes have limitations?

Negotiations between the defender and the CoR.

I really enjoyed the races when boats swapped places but boring when boat over start line 1st just extends its lead over next 6 legs.

That is always an issue with only 2 boats on the course to be honest. Even in the IACC boats, and the 12s, a good proportion of the races were decided in the prestart. Yes, there were some races for the ages, but a good proportion were 3 hour processions.