How fast can Alinghi's huge cat be?

It has the now becoming almost traditional wave-piercing bows. Traditional at least on many extreme multis such as, for example, those of the M2 class on lake Geneva.

It is large, and it seems like it will be hugely powered - though the not so extreme beam suggests that it cannot withstand really monstrous power (a square catamaran would really tack too slowly is I guess part of the reason).

It looks to be extremely light - I mean there's just the bare minimum (it could be several tons lighter than Oracle's boat, at least the one they've shown so far).

It will likely be optimised for high speeds.

Large ocean-going multis have achieved peak speeds of 40 knots plus, and about 33 knots over 24 hours.

So it seems likely that this toy can hit closer to 45 knots top speed.

Reactions?

 

Alinghi America's Cup Catamaran unveiled

...from a posting I made on another forum yesterday

America’s Cup: the Alinghi catamaran, July 4. 2009

text HERE


...and a few photos in the tent

WOW , imagine the loads at those connection points between hulls and crossbeams...even without the huge rigging loads that will be applied!!

 

Interesting report and interesting photos...some history as well

http://www.sail-world.com/USA/index.cfm?SEID=0&Nid=58599&SRCID=0&ntid=19&tickeruid=0&tickerCID=0

Check out that central fore-to-aft beam. I knew there had to be something like this being utilized, but it wasn't shown in those first photos:
From a couple of years ago a discussion of their 40 foot lake racing model....Vessel Substructure to Support Rigging Loads

And this quote from yesterday, Murray Jones, strategist and design team responsible for mast and rig programme: "This multihull is nothing like you've ever seen before in a big boat. It's like a small boat but scaled up. It's a highly finely tuned and engineered boat that's light. It's a piece of art. Alinghi 5 has evolved from the Swiss sailing boats, like the 41ft 'Le Black'. The basic engineering concept has come from 'Le Black' but everything else has come from the Alinghi design team, starting from a completely blank sheet of paper, with no preconceived multihull ideas. We started designing it and building it and we've done a lot of sailing and testing on 'Le Black' and the Decision 35s so we've incorporated some of the ideas we've picked up sailing these boats.

 

James Boyd, Daily Sail:
The boat shares the same engineering nightmare as Team Phillips in that she has a rear and centre crossbeam, but no forward beam. This is to reduce weight forward and the alarming tendency catamaran forward beams have to slam into waves (unless freeboard at the bow is enormous- and thus heavy - as it is on for example Orange 2).

With the main central crossbeam around 50% of the way back from the bow this leaves a huge length of bow unsupported.and remember what happened to Team Philips. However in the Team Philips case the bow snapped off due to a build error that had resulted in the carbon laminate 'blowing off' the Nomex core in this crucial area. We suspect that given the exacting detail of the Swiss team's engineers and builders this will not be the case here. Nonetheless the unsupported bows remain a questionable area of her overall structure

 

Interesting point Brian

Yes there's a huge bit of unsupported hull at the front.

I see two differences with Team Phillips:
- the Alinghi hulls are more like hulls on the M2 class that races on lake Geneva (about 30 boats built so far) where you've got wave-piercing hulls but the cross-section is such that you've still got a fair amount of volume not far from the bows thanks to the broad bottom. Team Phillips didn't have that at all, there was very little volume down below. Yes I know, the M2s are just 28ft
For more info see below (French only, but images speak)
http://www.am2.org/

- TP had a possible error in the construction (as you mention), yes. We're left to see whether things will be OK w Alinghi, but again given the very different cross-sections up front, there would be much better sideways resistance all else being equal.

- on the second voyage, the crew of TP abandoned her in a real storm, with winds at 11Bf where, according to skipper pete goss, she was still reaching peak speeds of 29 knots w no sail up because of the two wing-masts. So far it seems that Alinghi will have only one mast (two mast designs are always a nightware due to the added complexity), though it is said that it will be 50 metres (150ft) where those of TP were just 120ft - we don't know wheter it will be a traditional rig, or a wing, or mixed (and likely won't know any time soon as the first trials will probably be with traditional rig anyway). Alinghi is not meant to sail through any big storm at all - on the contrary, it has been said in interviews that it should be able to do 15 knots at 2Bf (4-5 knots of wind)

 

I believe you hit upon a reality there that will allow Alinghi to survive were TP did not....Alinghi will not have to content with these more violent situations...wasn't designed so.

I don't believe the hull section differences between Alinghi and TP is enough to make a difference. It was a debonding of a inner stringer that broke TP's bow.

And BTW, this 'new' bow shape is really not so new...maybe only in the reverse since. I'd be willing to bet the old NACRA cats beat all of these guys to the technology of wave piercing bows. Take a close look sometime. Probably the only difference is the NACRA had a plum bow, and now the 'fashion' is the reverse bow. The bottoms are likely the same.

 

Hey Brian, about Nacra

first let me say that in the old days I did sail on a friend's Nacra cat - and it was good fun!

now on the bow shape:

- inverted bows are fairly recent, as far as I can tell. Before that the maximum that people went to, was a vertical bow (like on the Nacras)

- hull shapes with more volume at the bottom, and sophisticated changes in cross sections, are much more recent. Until not so long ago it seems that most hulls on catamarans, were designed with little thought given to the importance of cross section apart from reducing wetted surface. As a result most everyone had a semi-circle for the part below the water. That's certainly what one sees on the Nacras (or on the Tornados). Whereas if you take a look at the M2's, you've got a thin (and inverted) bow, then you've got a section right after that with a lot of volume down below, then you've got a more conventional "minimum wetted surface" section.
Before this new paradigm, the only "solutions" were either to build very tall bows (like on the Nacra) to delay the time when the whole bow would go under water and risk tipping the boat forward (but at the cost of more windage and also not a real solution), or just ask the crew to please move around a lot to keep the bows lifted (like on the Tornado). No I'm not saying that this is perfectly fool-proof: the M2's DO occasionally tip over, at least two did last month in a 30 mile boat race (but the wind hit 30 knots and above)


So I continue to think that even thought the Alinghi design does include the risks that you pointed out, the fact that you have a wider cross-section, means there will be more natural resistance. But sure, 45ft of a thin unsupported hull, possibly reaching 35knots and more, that's always going to be a bit challenging...

 

NO, no, no. Go look at the bow shape on a NACRA 5.2, or most NACRA's for that matter. The 5.2 is at least 30 year old design...with MORE VOLUME at the bottom, and narrow decks that resist getting pushed under once they are under the water. I know the designers personally, and I represented their boats for a number of years, along with Prindle, and Stiletto, and Dragonly, and Fountain/Pajot..etc.

 

Spy Duck

...this is funny...courtesy of Latitude 38


Before heading north to Newport and Catalina, we stopped by the BMW Oracle compound — which is located next to Joe's Crab Shack in downtown San Diego — to see what was going on. The biggest noticeable change since last November is that they brought the big white fabric building in which the 90-ft by 90-ft trimaran had been built down from Washington. Since the sophisticated tri wasn't anywhere in sight, we presume she was inside getting worked on. A short distance from the building were what appeared to be three massive carbon fiber masts.

From the outside, the compound looked pretty quiet. As we stood looking at the rather small BMW Oracle sign near the guard station, we were approached by a duck who was eager to talk. "If you're looking for a finely crafted German automobile or some world class enterprise software, you won't find them in that building," he said. "No, what's inside that building is the trimaran that's going to be used in the next America's Cup. Alinghi, the Defenders, don't have to announce where the Cup is going to be held for a few more months, but it has to be held by the end of next February."

Surprised to meet a duck with such an interest in sailing, to say nothing of having a fine command of the English language, we just nodded and let him continue.

"Last year they had the tri sailing at more than 40 knots, which would be fast enough to get my feathers ruffled. Given the speeds and loads, somebody could really get hurt. No wonder that principle helmsman James Spitall and the rest of the crew wear helmets and body armor. And that there are EMTs on the support boats that chase the big tri. There have been rumors around the nest that Larry Ellison, owner of the campaign, sailed on the tri once, and that was enough for him. What's even more telling is that Russell Coutts, the America's Cup legend, is rumored to be afraid of the boat, too. But I think that's just gossip, don't you?

"You probably want to know what they've been doing inside that building since they stopped sailing operations in February," said the loquacious duck without giving us time to answer his question. "I'd probably end up as Peking duck on the BMW Oracle crew menu if they knew that I told you, but they've been making a hard sail for the trimaran. Sort of like the one Dennis Conner used when his catamaran beat the Kiwi 'big boat' monohull in the funky America's Cup in San Diego many years ago. I also heard that something like $5 million was spent on either modifying or replacing the two outer hulls. If anyone is feeling sorry for syndicate owner Larry Ellison, they don't have to. My 401K for ducks has taken a beating in the last year, but not from Oracle. They had an operating income of almost $8 billion in the last quarter, and if I'm not mistaken, Ellison still owns something like 20% of the company. So he's not having to chase the America's Cup with a cup in his hand."

"But when is the big tri going to be test-sailing again?" we asked.

"I'm glad you asked," said the duck, "because the big news is that they'll be sailing shortly. If you're in San Diego, you won't be able to miss her. But at the speed she travels, you won't be able to see her for long — unless you're in one of those F-18s flying out of North Island."

Since the duck seemed to be such a know-it-all, we asked him who he was picking to win the next Cup. "Some chicks and I were discussing the America's Cup the other day, and figure BMW Oracle has their work cut out for them. I'm just a duck, but I figure this is going to be — because of the extreme speeds and risk of personal injury and boat destruction — the most NASCAR-like America's Cup ever."

- latitude / rs

 

We know for sure that the BMW/Oracle boat has lifting foils(foil assist)-has anyone seen any mention that lifting foils will actually be used on the Alinghi boat?

 

Strange America's cup