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New imoca boats

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10 hours ago, frozenhawaiian said:

2 question about that. 

1. I thought that the 1st gen HB foiler was being replaced because it had some major structural issues after tear assing around the planet during the last VG

2. aren't the VOR , or I  guess it's "the ocean race" now imoca boats going to be one design? so this will be a training boat for mark and charlie?

The boat was still in fine enough shape to reach Guadeloupe first in the route de rhum. I believe they will race in the TJV and train with this boat before building a fully crewed boat

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Do we know if this latest generation are going to be carrying a kite or have they completely switched to furling headsails?  

 

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IMOCAs haven't carried what we would call kites for quite a while, even their 'downwind sails' are flat

 

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On 9/7/2019 at 9:08 PM, Sailbydate said:

Agree. The WORST thing IMOCA could even contemplate.

There are 6 (IIRC) new generation boats launched right now. No way that would be happening were the class OD!

Pretty sure it's 8.

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On 9/24/2019 at 3:54 PM, Tito said:

How "flat" are they making them now? 50% mg?

i dont know the actual % numbers but they look way more like my Tri's Code zero than our VMGreacher

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ps on my Open50 we stopped using the asymmetrics, expect in v v light deep down wind conditions... was faster (and much easier) to use J1 and staysail in any sort of breeze

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29 minutes ago, SSolo said:

ps on my Open50 we stopped using the asymmetrics, expect in v v light deep down wind conditions... was faster (and much easier) to use J1 and staysail in any sort of breeze

didn't know open 50's were still a thing.

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On 9/24/2019 at 3:08 PM, SSolo said:

IMOCAs haven't carried what we would call kites for quite a while, even their 'downwind sails' are flat

 

To me the foresails of an IMOCA have more in common with multihulls these days than say a class 40 or a TP52, I mean just look at the gennakers these days, at least, when they use them. 

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12 hours ago, Raptorsailor said:

didn't know open 50's were still a thing.

There are still a number around
i owned %& raced Pegasus (ex Artforms) the Owen Clark Open 50 after Phillipe Khan had turbo'd it with a 3m Bowspirt and another 3m on the rig and a metre on the keel... it was already the fasted Open 50, then even quicker
Pegasus's  sails were flat... the IMOCAs even flatter - as you say more of a Code 0/jib similar to that i have on my Seacart 30 Tri   - like multis the IMOCA are pulling the wind sooo far forward its not downwind sailing even when downwind

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just saw this on facebook. stern lifting on charal. looks like she's fully foiling but no rudder foils.  what kind of voodoo is this?

 

 

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1 hour ago, frozenhawaiian said:

just saw this on facebook. stern lifting on charal. looks like she's fully foiling but no rudder foils.  what kind of voodoo is this?

 

 

Perfect conditions and the right sail choices/settings.Beyou and Pratt really have mastered it. They only get a few seconds of flight but it is beautiful.
Just had an elevator on the damn thing and you're set.

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Pretty goddamn impressive without rudder elevators!  Must have also become really technical with stacking.

 

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Holy shit! I guess that's the advantage of launching so much earlier than everyone else. 

7 hours ago, frozenhawaiian said:

just saw this on facebook. stern lifting on charal. looks like she's fully foiling but no rudder foils.  what kind of voodoo is this?

 

 

 

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Appears the key to winning is who can push the longest. Sleep deprived in the southern ocean, do you really want to try to maintain constant foiling? Of course not, but someone will, so you have to give it a shot. Watching them this time is gonna be so frigginly awesome  cool.

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On 9/26/2019 at 8:02 PM, frozenhawaiian said:

just saw this on facebook. stern lifting on charal. looks like she's fully foiling but no rudder foils.  what kind of voodoo is this?

 

 

May be there is enough longitudinal distance between the keel and the foils to make the keel work as an elevator. If that's really the case, it must be pretty unstable (short lever arm).

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2 hours ago, Panoramix said:

May be there is enough longitudinal distance between the keel and the foils to make the keel work as an elevator. If that's really the case, it must be pretty unstable (short lever arm).

I am more inclined to believe that heeling angle allows the rudder to act as the elevator (as it is no longer entering the water perpendicular to the surface but nearly at 45deg). This was a suggestion in HB thread and seems plausible looking at Charal as well. This also offers much more longitudinal separation than keel-foil. It doesn't look like the boat are heavy on their bottom and I don't think much lift from the rudder is required to achieve this (only my take).

When HB was announcing a revolutionary boat, I was kind of expecting a Y shape foil with two elements in the water to have some longitudinal separation and allow for proper full flight foiling but I don't know if it is within the rules or if it hasn't been considered by any team (or discarded). That would have been quite instable in any case as they can't have movable flaps, the separation would be limited, and it would induce huge loads on curved shapes. 

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4 minutes ago, Lakrass said:

I am more inclined to believe that heeling angle allows the rudder to act as the elevator (as it is no longer entering the water perpendicular to the surface but nearly at 45deg). This was a suggestion in HB thread and seems plausible looking at Charal as well. This also offers much more longitudinal separation than keel-foil. It doesn't look like the boat are heavy on their bottom and I don't think much lift from the rudder is required to achieve this (only my take).

When HB was announcing a revolutionary boat, I was kind of expecting a Y shape foil with two elements in the water to have some longitudinal separation and allow for proper full flight foiling but I don't know if it is within the rules or if it hasn't been considered by any team (or discarded). That would have been quite instable in any case as they can't have movable flaps, the separation would be limited, and it would induce huge loads on curved shapes. 

I hadn't thought about this. But then when you bear away the boat goes nose down and when you luff nose up?

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11 minutes ago, Panoramix said:

But then when you bear away the boat goes nose down and when you luff nose up?

I would say the opposite actually as during bear away, angle of attack will increase leading to more lift from the rudder and nose going down. While in the opposite situation, rudder will "dive" under water and pointing nose up.

Was trying to find example in above video but the sequences are too shorts to come to any conclusion, looks plausible at 00:26 but we don't know the wind conditions (end of a puff?).

 

I also want to say that despite liking that theory, I am not 100% convinced as rudders still points slightly outwards rather than straight down when boat is at rest. Second option would certainly generate more lift if this is what they want.

HB.thumb.jpg.3289661303ae1fda9b41bd478558396f.jpgCharal.jpg.7aaeb1192e6ec9950a306e84690a21da.jpg

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@Lakrass

I think we were saying the same thing for the nose up/down trim of the boat vs rudder.

 I am not 100% convinced either, as you say the angle to the vertical of the leeward rudder once the boat is heeled is minimal, thus the rudder would have little authority for pitch control. This introduce pitch / yaw coupling, intuitively I think that could probably lead to weird oscillations. May be they've got it sussed out but it feels hard to master to me.

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Nice video, it adds a bit more to the previous ones. Several observations:

- Looks very unstable despite pretty flat water. Wonder if it is under autopilot or manual.
- Looks a bit heavy on its bottom, we probably gave too much credit to the lift produced from rudder but doesn't seem to be zero either.
- Still seems to have a nose up attitude when luffing and nose down during bear away. Adds complexity for autopilot configuration? I think it was Samantha who said the autopilot was doing a better job than them. I guess they still need adapting to new behavior.
- Can't picture this kind of boat in agitating sea and the only crew going to sleep (or only going to sleep in such boat for that matter).

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I agree with you, I think that there is some coupling between yaw and pitch.

I am not sure that comfort inside is that bad (to IMOCA standards!) as the slamming might be reduced. Nevertheless that must be really stressful as I imagine the autopilot risks nosediving seriously with the forward half of the boat ending completely buried in the sea and the boat slowing down to a few knots within a split second.

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4 hours ago, Lakrass said:

Nice video, it adds a bit more to the previous ones. Several observations:

- Looks very unstable despite pretty flat water. Wonder if it is under autopilot or manual.
- Looks a bit heavy on its bottom, we probably gave too much credit to the lift produced from rudder but doesn't seem to be zero either.
- Still seems to have a nose up attitude when luffing and nose down during bear away. Adds complexity for autopilot configuration? I think it was Samantha who said the autopilot was doing a better job than them. I guess they still need adapting to new behavior.
- Can't picture this kind of boat in agitating sea and the only crew going to sleep (or only going to sleep in such boat for that matter).

Agree with most of what you say here.

I wonder whether different teams are approaching this from different perspectives.

The Charal style foils with hard elbows would not be able to alter the immersed area of foil through either retracting or extension of the whole foil, the lifting part of the foil remains fully immersed and its attitude remains relatively constant with respect to angle to the hull and rig - but they may be compensating lift characteristics through roatation of the AOA on the whole foil. The stems of the Charal foil is primarily a structural arm to hold the 3 lift generating faces of the foil - which do the actual lift work.

Hugo Boss with more constant radius curvature of the foils has a little more opportunity to increase or reduce foil surface through extension or retraction of foil inward/outward as well as a few degrees rotation of AOA, giving a more complex system to dial in - but ultimately more modes to use for differing angles, sea state and velocity.

Also think that the helm station and bunk of HB is positioned around the centre of boat pitch - allowing a somewhat violent pitch and yaw tendencies of these boats to be tolerated for longer. AT has direct experience of the consequences of fatigue.

Will HB have had enough time and testing to dial in their settings against Charal in the TJV - honestly, probably not, but then they will still be on the steep part of their learning curve, whilst Charal is naturally flattening off..... Also testing versus racing puts the blowtorch to even the best prepped teams. Charal has an advantage here.

Come Vendee Globe - the boats with best settings will clear out very Fast.

 

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It seemed like there was a notable drop in speed as the boat pitched a dug its stern in - tbh I actually ended up thinking the amount of pitching/hobby horsing looked kind of ridiculous. The boats are insanely impressive but that constant pitching in flat water makes it look so unstable - would be really interesting to see how HB compares with her foil design...

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On 10/6/2019 at 12:59 PM, Panoramix said:

I agree with you, I think that there is some coupling between yaw and pitch.

I am not sure that comfort inside is that bad (to IMOCA standards!) as the slamming might be reduced. Nevertheless that must be really stressful as I imagine the autopilot risks nosediving seriously with the forward half of the boat ending completely buried in the sea and the boat slowing down to a few knots within a split second.

And that’s a problem because?

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On 10/6/2019 at 12:59 PM, Panoramix said:

Nevertheless that must be really stressful as I imagine the autopilot risks nosediving seriously with the forward half of the boat ending completely buried in the sea and the boat slowing down to a few knots within a split second.

I think this is why they are going to have to sleep feet forward...

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5 hours ago, Amati said:

And that’s a problem because?

@Ultraman answered your question. Flying across the boat is not the nicest thing.

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5 hours ago, Panoramix said:

@Ultraman answered your question. Flying across the boat is not the nicest thing.

;)

 

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yes racing boats,, but you could hurt yourself.. Dont be silly!

 

it is also balance act to save energy and make utmost of sailing in racing conditions. Sailing around world without sleeping in a washing machine. WTF!

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