Twenty Knots

[colemj]

I found this statement in an article on the AC72's: "Grinders have controls to shift gears on the pedestals and to change what is being powered by the pedestal they are on - trimming the jib, hoisting the gennaker, raising or lowering the daggerboards."

Leads me to believe in multiple hydraulic systems and not a single system.

This from an article in Wired: "for the AC72, the designers started by estimating the maximum horsepower an athlete could exert over a 30-minute race and worked backward from there. If the AC72 were any larger, mere humans wouldn’t have the muscle to change the angle of the wing or to lift a secondary sail."

Leads me to believe the grinders aren't "easy".

Mark

[barnakiel]

Originally Posted by thomm225

(...)

He also went for the best side of the start line, (...)

We have seen AC72 boats able to use the better angle from the windward side and roll over the lee side boats.

I think we must watch and adjust our slow / monohull based opinions. They do not seem to always hold true for these new boats.

I think ability to get on the foils first is a huge factor in who gets round the first mark first. And getting on the foils may be easier (my wild guess here) for the windward boat.

Hence the 'best' side of the start line may be a movable feast.

Not opinions, just observations.

b.

[colemj]

Originally Posted by barnakiel

I think we must watch and adjust our slow / monohull based opinions. They do not seem to always hold true for these new boats.

We have a catamaran (I can't say fast) and nothing holds true for us either.

Mark

[44'cruisingcat]

Originally Posted by Bash

Well, the coffee grinders on both boats are charging hydraulics. Not as tough as when they gear directly to winches. (Not to take anything away from Dalton.)

Nope, this is incorrect. Hydraulics are just another way to reduce "gearing" You don't get more work out than you put in, either way.

re the 20 knot (or thereabouts) windspeed limit for racing - the boats were making a VMG to windward of 17 knots in 20 knots TWS, (how good is that!) so would be seeing around 37 knots over the deck!

[colemj]

In Bash's defense, I think he was referring to the instantaneous work on the grinders. In other words, his postulate is that the same amount of work is done, but it is done for longer times on "easier" grinders for the hydraulics.

I think that is still wrong - both types have gearing and both types are "hard" in direct gear and "easier" in ratio gears. The only thing different is that these boats require much more grinding than past boats.

The windspeed limit is artificial - it was applied after a boat capsized and a crew member was killed. That was very early on when the crews were new to the boats and had not adjusted to foiling, bearing off, etc. The boats (and crew) can handle more wind - I've watched them practice in 25+ several times.

Mark

[thomm225]

Originally Posted by barnakiel

We have seen AC72 boats able to use the better angle from the windward side and roll over the lee side boats.

I think we must watch and adjust our slow / monohull based opinions. They do not seem to always hold true for these new boats.

I think ability to get on the foils first is a huge factor in who gets round the first mark first. And getting on the foils may be easier (my wild guess here) for the windward boat.

Hence the 'best' side of the start line may be a movable feast.

Not opinions, just observations.

b.

I haven't watched a lot of the racing until now, but I just bought my first monohull in 2011.

My first catamaran I bought in 1992, a Hobie 16. Since then I've had another Hobie 16, NACRA 6.0, and a singlehanded NACRA F-17 with spinnaker that I could hit 23 knots on.

Lucky for me, I got to move to Florida and race 10 months out of the year against some of the best catamaran sailors in the USA in 1996. I've had around 450 starts. Forget about who gets up on the foils first at this point (as Spithill did in race 4) that's a given now.

I just think Spithill has the knowledge and the tactics to go forward after the information he gained in race 4.

My opinions are not monohull based. I believe Spithill will not get into anymore slow tacking duels but use the boat's speed like he did in race 4 to extend and win while maybe covering loosely.

I didn't start sailing until age 35, Spithill started when he was just out of diapers. Again check Spithill with a monohull. He's pretty awesome in the prestart on anything that floats:

L.V.Cup 2007 - LR-OR Day 5: Amazing Prestart of J.Spithill - YouTube

[Bash]

Originally Posted by Paul Elliott

I question this. I've seen some grinders working slowly and sporadically, obviously controlling something that required a little finesse, and on the neighboring pedestal another grinder cranking as fast and hard as he can. This isn't the behavior we would see if they were all feeding a common pressure reservoir.

Some of you may want to do a bit of reading about these systems.

Here's an article where one of the Artemis grinder Craig Monk says that grinders on the new boats are grinding about 80% of the time, as opposed to about 20-30% of the time on the previous boats. It also mentions how you can have all the pedestals working on the same winch.

Genn Ashby talks to Roger McMillan about trimming an AC72 wing

Here's an article that came out in Sailing World a few days ago about the hydraulic pedestal grinders that Harken developed for Oracle.
America's Cup 34: The Power of Oil | Sailing World

[Nicholson58]

Originally Posted by nicholson31

this is a question that can only be answered according to the boat, skipper/crew and experience.
Having said that, 20k and under i go full sail, its in my opinion, the optimum wind for my boat. 20-27ish 1 reef and above that up to 35, 2 reef points. Yes you can push harder but its nice to have room for those 10-15 knt gusts.
gjordan hit the nail on the head, they are not "sailboats" They are high performance hydrofoils in my opinion, to call that sailboat racing almost seems Wrong!!
Terry

Totally correct. We reduce sail above 18 - 20 depending on sea conditions, wind point and air temperature. Cold dense air and we reduce earlier. In a rediculous blow on Green Bay we operated the main at about 1/2 furled and cutter staysail to weather - no problems. Some boats are very stiff and well suited to snotty weather and others are quite tender. If you know what to do, the light boat can be sailed in big wind but you will fly a blade and deeply shortened main. You will also likely be uncomfortable and on the edge.

Our rig is cutter-ketch; 55,000 disp. I prefer to keep my heel below 20 degrees. The 135% Quantum fusion #1 is made to fly partly furled although I prefer not to. If my #1 was 120% the metrics would be different. The jib is around 200 pounds and very stiff so it stays on the furler. The cutter jib is for high wind. With the mizzen, we have a lot of choices. Main & Mizzen are roller furled in-mast and the main is electric. We use a Milwaukee 1/2 inch 28 VDC drill & winch adapter to power the manual winches and the #65 primaries are direct powered. We have sailed down wind in high winds and 12 foot seas at 7 to 11 knots on the main alone.

[Paul Elliott]

Originally Posted by Bash

Some of you may want to do a bit of reading about these systems.

Here's an article where one of the Artemis grinder Craig Monk says that grinders on the new boats are grinding about 80% of the time, as opposed to about 20-30% of the time on the previous boats. It also mentions how you can have all the pedestals working on the same winch.

Genn Ashby talks to Roger McMillan about trimming an AC72 wing

Here's an article that came out in Sailing World a few days ago about the hydraulic pedestal grinders that Harken developed for Oracle.
America's Cup 34: The Power of Oil | Sailing World

Thanks for sharing these. I had seen the Sailing World piece, but not the other.

I have to say though, that none of this supports your contention that the grinding peak loads are easier (they may be, but we can't tell from these articles). They also don't suggest that the average amount of grinding power is less than in previous AC boats. It could very well be more, and in fact, it sounds like it is. And I see no mention of hydraulic reservoirs. Yes, all the grinders can be connected to a single output, but it seems that they usually aren't.

But this is actually neither here nor there. The men on these boats obviously work very hard. I'm interested in these hydraulic systems, but I'm not much interested in arguing about them.

[colemj]

No one has questioned the amount of time grinding or the ability to have everything go to a single winch.

The question was whether the grinding is "easier" than traditional winches, and whether everyone is working on the same system when they are grinding.

Your articles show that all of them can be put to work on a single system if necessary, but also that this is rarely the case, since so much needing hydraulics is happening at once. For example, Ashby decries that he often doesn't have enough grinders on particular systems at time because they are controlling something else.

The Ashby article also talks about the grinding control being a 1:1 sheet control - which leads one to believe that the grinding effort is great.

Ashby loves that wing and neatly describes how racing these isn't just a drag race and that "the opportunity for gain/loss during the race is greater than it has been in the past" (his words).

This event could very well go pear shape in the remaining races, but one thing is for sure - the races so far have been closer to what people "remember" as traditional AC racing than actual historical facts support. After many years, we finally have real AC competitive racing!

And there isn't any pressure reservoirs at all - the grinders are direct pumps to the hydraulics. The grinding IS the pressure. There is, of course, some fluid reservoir(s) somewhere. The rules prevent stored power larger than that needed for basic engineering housekeeping (keeping valves closed, for example).

Mark

[Nicholson58]

I like this tool. grinding is easy for anyone. It will pull my 180 # up the mast (80 ft) and it makes furling the 135% jib a piece of cake.

Milwaukee 1/2 inch right angle 28 VDC. Use the 2:1 low speed reduction option for the gear-head and motor direction 'clockwise' so the chuck does not unscrew from the gear-head. You can find these Factory Rebuilt on line for about 2/3 of the new price. Google the winch adapter or make one from hardened key-stock.

[colemj]

Dang, that would have saved the AC teams some dough! Unfortunately, it doesn't fit the winches and the AC rules forbid it...

Mark

[thomm225]

Originally Posted by barnakiel

We have seen AC72 boats able to use the better angle from the windward side and roll over the lee side boats.

I think we must watch and adjust our slow / monohull based opinions. They do not seem to always hold true for these new boats.

I think ability to get on the foils first is a huge factor in who gets round the first mark first. And getting on the foils may be easier (my wild guess here) for the windward boat.

Hence the 'best' side of the start line may be a movable feast.

Not opinions, just observations.

b.

I was trying to get across before that my opinions are not monohull based, but you do have a point here about the speed.

Your opinions can be monohull based or catamaran based, and it still will not compare to the speed of these boats. Once Spithill got his boat up on the foils in the prestart on race 4 it appeared he had control. The boat just took off.

I'm thinking Spithill's experience and ability in the prestart (on any type boat) can possibly erase the Kiwi lead. That plus now his team has a few races under their belt.

They've made mistakes, but at the same time have discovered a racing style that appears to work which is once the boat is up to speed use that speed as long as possible..........

That said, there still should be a favored side of the start line. Whether are not you can get there first, on the right tack, and at speed is the question.

[thomm225]

Looks like Team Oracle USA still doesn't realize they are racing catamarans.

You do not shut the boat down like they did at mark 2. You round and extend to keep your speed up. John Kostecki may be in trouble if he called this type of tack.

[colemj]

Not to mention that athletes at their level suck up a mistake and get back in the game. I think pulling their card to "regroup" was a bad choice, given how fragile these boats are and how many races are potentially ahead of them.

Mark