What's up with the America's Cup

I just found some You Tube videos from "World on Water" that show the boys practicing in Bermuda.

This is from yesterday and it also shows the pedal power training for ETNZ, they are going to use their feet instead of their arms to grind the hydraulic pressure.

I'm wondering why they are using big heavy guys over 200lbs with big upper bodies instead of some out of work Tour De France types that only weigh 135lbs and can pedal harder, all day?

https://www.youtube.com/watch?v=Yzh5VfDN80E

easy - bicyclists are afraid of the water

but now my baseless guess would be that they need "power lifters" vs. "endurance guys"

Look at how bow down they all seem to be when they are on the foils. At the beginning of that video you see the Brit team stuff a bow during a tack/gibe. At first I thought it was a Brit boat only thing, but later in the video you see all the boats are sailing like that, almost all the time when they are foiling. I wonder why.

I was curious about that bow-down hull attitude as well.

Perhaps it is the best way to keep the mast as vertical as possible? I presume with a wing you don't have as much mast rake as you would with a sail since the draft profile would be much different.

in something totally not related (cuz i'm the king of hijack)... Timbo I've got the Naples - Key West race this week (Thursday down, Sunday back), so I could use your help next year if you can keep your calendar clear... & Carlos if he's still alive

How does the bow-down attitude surprise you? Did you all forget that these are sailed by non-catsailors???

All kidding aside, don't forget that the platform (including crossbars) is another important foil at these speeds. I'm willing to bet that plays a role.

Mike

if you look real close ... you can see a fat bastard on the bows
he's probably weighing it down
[img]https://www.thebeachcats.com/galler...p;g2_itemId=127684&g2_serialNumber=4[/img]

The bow down attitude is the result of restrictions in the angle of the rudder foils and the different speeds upwind vs. downwind.

Upwind, the boats are relatively level; the boats are moving 25-30 kts. A higher angle of attack is required on the rudder foils to lift and stabilize the back of the boat.

Downwind, the speed increases to 35-40 kts; a lower angle of attack on the rudder foils is required to achieve the same lift, so the boats assume a bow-down attitude.

Remind me to bid it off next year, tell me around April 5th, when our May bidding opens!

I just saw Carlos last Saturday, he's now in Miami going through 737 school, he'll be flying for Miami Air, and he's looking to move to somewhere down there. He might be available next May, heck, he may be retired, again, and again by then!

I wonder why they don't change the rudder foil angle of attack by raking the rudders just a little bit, like they do the main foils, unless changing the rudder rake is prohibited by the new rules.

There's your answer. Limited to 3 degrees of movement.

Any ideas on why it's so restricted?

Mike

Yeah that seems like kind of a dumb rule considering they want a balls out foiling catamaran going as fast as possible, why restrict the rudder rake when so much other stuff is made for going fast?

For a detailed answer to the bow-down attitude watch this short video by Slingsby. Sign up for the Oracle Facebook page and get regular news videos from them. Really well done and some great video of them flying (and of Jimmy falling off ...again!).

Facebook link to Slingsby explaining bow-down

Latest news (May 10)...Oracle just capsized (again!) but no damage and nobody hurt.

Link to video: https://twitter.com/i/videos/tweet/862441427120336897?

Mike

3 degrees according to that video, but my question is, why are there any limits?

I'm sure part of the box rule that the defender put together. The question of "why" is probably best left to them.

Maybe to limit the design options (and part of the arms-race)? In doing so, they may limit the wide variety of performance between boats/designs and therefore keep the racing somewhat close?

I am looking forward to the possibility of watching fleet racing at 40+ kts downwind.

Can you imagine flying toward C-gate with 4-6 other boats and closing speeds on opposite gybes approaching 70 knots? yeehaw! Talk about the tactician having an anyerism

These cats are what, 45 feet long?

And they are making nearly the same speeds as the 72' cats from 3 years ago!

Wow.

It used to be that a longer waterline made for a faster boat, but once they get up on the foils I guess it comes down to weight and sail area for determining max speed. Foil mechanics and control are becoming more important than waterline length.

More importantly than just momentary boat speed is the total time up on foils. Jimmy, Dean, and Ben have all said in recent interviews that foiling the entire race is possible. In recent practice races you could see examples of where one boat fell off foil and slammed down, slowing let's say from 40 mph to 20 mph, that the other boat picked up so many boat lengths that the race was basically over. That speed difference would give them 10 boat lengths in just 15 seconds of "down time".

Fast and steady wins the race.

50 footers and not nearly as fast, they are way faster that the 72's around the course.

seems that the rig and hulls are not as important as the foils

I do realize that's what Oracle said about their bow down...but it also stands to reason that they would want to rake their rigs more vertically when sailing downwind and rake them back upwind...all I'm sayin. There is no advantage for everyone to spill their techniques - trust nothing any team says at this stage

Interesting interview

https://www.aopa.org/news-and-media/aopa-live?watch=c4aadea5730334ec84b4a514aafe2f37

The smaller bicycle racers do the best in the mountains only because they have less weight to lift all of those meters. Their power goes into overcoming wind and rode drag AS WELL AS lifting their own weight up the mountain. The best sprinters are usually bigger guys with more raw power but they fade badly in the mountains due to the extra weight that has to be carried up the mountain. So good sailboat bike riders (that's gonna take some getting used to) use ALL of their power only to pump hydraulic fluid so the focus is on only who can produce the most power; any lifting is provided by the boat, making them more like the sprinters - bigger and stronger. Oracle is looking at converting the tactician station into a bike so that he can keep his head up, produce more power, and be well stationed to talk to the helm.

This whole bike thing has a tinge of "absurdity" to it.

Cap'n Don says it's a hoax.
Cap'n Bob says it's a fad.

But NZ has a long memory of yelling "Hydro, hydro...!" back in San Francisco when pressure went down. I bet it was high on their "never again" list.



Listen in at about 1:48
NZ f-up

I love watching these old videos of SF. Would someone post once again how to embed a video, please.

Legs have more power than arms (well, except for kenny), so I would have thought a recumbant type setup with proper gearing could do the trick.. I hadn't thought about in-line bicycle style pedaling. But I guess you could stand up and crank (can't do that in recumbant format)

Dave, I don't see it anymore = perhaps when Damon made the upgrade (march) the feature to embed a video has disappeared and all you can do is post it as a link

I think it is supposed to work with only the share url

Let's try


https://youtu.be/toYyzaAE-SA

That doesn't seem to work, let's try the video page url

https://m.youtube.com/watch?v=toYyzaAE-SA

I'll look into it.

https://m.youtube.com/watch?v=toYyzaAE-SA

Jake, The crew was substantially reduced to help lower the cost of entry for an AC team (that old head count issue that all organizations deal with) and later on it developed that there were times when the power needs were beyond what the crew could create in the moment even though they have made massive efforts on developing the physical output of the crew. That is why there has been so much hydraulic system and equipment design and development for this AC. They need to apply the hydraulic power as efficiently as possible and even then be able to accumulate power around the course so that they have enough to meet "peak demands", like the leeward mark when the foils are changing and adjusting and there are big trims on the wing and jib. The partner companies have been finding applications for this work on systems they can use in their native industries, especially airliners. So in that engineering sense it is not absurd but on a conceptual level it definitely is!

I will be there to watch the end of the quarterfinal series and I am really hoping to get closer looks at the boats and equipment; not likely except for maybe the odd boat out at that time, probably France. The teams that are out at the end of that series will probably not be in the mood to let gawkers in but I will look if I can. I have read that New Zealand is developing 30% more power than the grinding teams so maybe they will not need the accumulators that the other teams have had to develop. That would save weight and complexity... it would be interesting to know these technical details but I am not sure if we ever will.

Mike,

I didn't mean in the sense of technology or whether or not it made sense - I just meant in the sense of sailing. I'm very familiar with the systems in use on those boats. I'm all for multihulls, wings, foils, etc. at the bleeding edge of the sport but you take someone not familiar with the America's cup and show them the New Zealand boat, everyone jumps to the conclusion that they are peddling props on the bottom of the boat. It takes a lot of explaining through furrowed brows that the bicycles (another mode of human transportation) were mounted to a sailboat (typically considered relatively slow) to build up hydraulic pressure so the two or three guys at the back of the boat can push buttons and control the sails and foils and make it go. To someone not fully invested in sailing as a sport, it sure as hell seems like a lot of complication to go 40 miles an hour....hence the tinge of absurdity.

Jake, I'm sure they said that back in the days of the galley boats...

Lots of dudes sitting at oars while a guy in the back pounds a drum and pushes buttons (or rudder)

But you engineers could help me understand the most efficient way to store hydraulic power. Since liquids are essentially non-compressible, are they building up pneumatic pressure to apply the hydraulics later? If not what is the mechanism used to "build" up the power to be used "during peak demand"?

I'm no engineer but i did stay near a Holiday Inn last night...

i think they use this type of machine to build and store the hydro power

oh, that's easy

I know on most big jets there are hydraulic accumulators that do have a nitrogen precharge of around 1000 psi. This accumulator system is usually only on the brakes. The problem is, once you pump the breaks a couple times, the precharge is gone, so you need hydraulic pumps (either electric or mechanical off the gearbox) to recharge the system.

There are period of very high demand for hydraulic pressure on an airliner, which are when the gear is retracted right after takeoff and at flap extension/gear door retraction after extension on configuring for landing. The 767 and 777, in addition to electric and mechanical hydraulic pumps, have an air driven demand pump, which use bleed air off the engines and only kicks on during periods of high demand, or if one/both of the electric/mechanical pumps fail.

so you don't have to pump the brakes?

So does anybody have any idea if/when/where we will be able to watch any of the America's Cup racing here in the USA?

no sooner did I ask...
http://www.sailingscuttlebutt.com/2017/05/22/us-broadcast-schedule-americas-cup/

You can always go to the America's Cup website for the latest.

NBCSN Viewiing schedule

What does the SDD mean in the footnote?

(Edit: I see it now...*SDD (same day delay))

When NBC did not do the broadcast a couple of years ago.
I tried the America's Cup app with my phone, when the app first came out. I tried to connect to the first event, but could not connect to the live stream. After a bit of arguing over multiple emails and a couple of calls with them I got my money back for the app.
Since then I have used the internet with my VPN. I set my VPN to a server to a country where they were streaming live. Then stream the broadcast.
This site shows where how you can view the events by selecting your country How to watch The 35th America's Cup in Bermuda

Here's the latest on the AC racing yesterday, from You Tube:

https://www.youtube.com/watch?v=anh5lNUwef8

I've listened to a few interviews. They have a long way to go to earn my respect as sportsmen. Ainsle didn't once mention concern for the health of the guys he nearly killed. Burling basically admitted to calling for an umpire call out of desperation, and had the gall to say that in all pro sports, you play to the whistle. Yikes...

Mike