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  #61  
Old 04-12-2007, 11:45 AM
Chris Ostlind Chris Ostlind is offline
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I also wish them good fortune in their pursuit. There are just so many things to consider when pushing a speed envelope. I know, for instance, that when I did race, the car had far more potential in the short term than did I. I was the one who had to get in better shape, focus more completely when driving and be aware of more things around me.

It does take a awhile to get good at anything like this. Well, unless you were born a beautiful freak of nature like Michael Schumacher or Fernando Alonso, which I was not.

Truly, I'd be surprised if they go right out and hammer the record in the first year after all this refit work. I do see it happening as soon as next year, though, and that is extremely fast R&D work at this edge of the blade.
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  #62  
Old 04-14-2007, 08:22 AM
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Guillermo Guillermo is offline
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An interesting video from Sailrocket:
http://www.sailingscuttlebutt.com/media/07/0409/
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  #63  
Old 04-17-2007, 07:58 AM
antoineb antoineb is offline
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Hydroptère: 47.6 knots top speed (instand)

I just watched the video from their recent record (still to be confirmed by WSSRC) over 1nm.

I noted two things:
- at the end of it, they post the new max speed reached, 47.6 knots (vs. 47.2 before, so marginal progress)
- clearly that day while the sea was indeed fairly forgiving, the wind was not very strong: many signs suggest 20-25 knots at best, and quite a few times during the 1nm video the crew talks about making sure they catch this or that wind gust (and reaching over 45 knots in the gusts, but falling below 40 in between), which typically one does not worry about when there is a good 25-30 knots of stable wind

I infer the following:
- we have not seen the best Hydroptère can do in terms of record speed on either the 1 nm, or 500m
- on the 1nm it may imply that the boat has the potential to set an absolute speed record at 42-43-44 knots, which would really start to look difficult to match. On the 500m however I am ready to envisage 45-46 but I am not sure they can go much faster - unless one day they go all out, and better, have fitted a wing on the craft

Overall, I continue to believe that above 45 knots the aerodynamic drag just becomes huge, and that unlike other designs (like Macquarie, or even Techniques Avancees whose old record they've beat) Hydroptere have not spent much (any?) time on this because their main aim was (and still is) to establish ocean going records. So, as I say above, I believe that we'd need an aerodynamically optimised Hydroptere for any major records to be beat by a large margin. But I don't think the sponsors will pay for this before we've seen a few ocean going records.
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  #64  
Old 04-17-2007, 08:08 AM
antoineb antoineb is offline
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on Sailrocket: based on the story, the chaps on the project seem like really nice guys and I can only wish them the best of luck.

However if you look at their design, it is basically a windsurfer, with a bigger sail, and a LOT of drag added. In the best case and at full speed, maybe the thing will have reduced its drag to not too much more than a windsurfer - but I'm afraid that's not good enough.

Therefore, almost by definition, I think Sailrocket will probable UNDERPERFOM a windsurfer, all else being equal. I am not saying they cannot reach 40 knots, but I'd be very, very surprised if they ever got close to the absolute record.

Again, i can only regret my conclusion, because they seem like a great bunch and they do a lot of the construction work themselves and have small means and all - BUT I really think that there is a fundamental design flaw, which implies that the craft cannot beat the record.

Sorry, apologies, all this.
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  #65  
Old 04-18-2007, 09:12 AM
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boogie boogie is offline
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Quote:
Originally Posted by antoineb View Post
was having dinner w an old friend the other day, and I mentioned the Hydroptere but he was not really with me because he is much more into motor sports.

so I came up with this for him:

imagine a team develops a rally-raid car to cover long distances at record speed in rough terrain

Now imagine that, for fun, after a few successful high speed tests in rough terrain, the team decide to take that car out on a racing circuit where Formula One races take place.

and now imagine that on the long straight the car comes up to within 9 percent of the fastest speed ever recorded on that circuit in a Formula One car, i.e. say 330 kph (206mph) vs. 360kph (225mph)

and imagine further that, on a full lap, the car ends up going actually 0.9 percent FASTER than the best average speed on a lap, by a Formula One car

and remember that, in the meantime, it is still expected that the rally-raid car will be the fastest on anything longer, and in terrain.


my friend's jaw dropped, and he said, "geez, that would make massive headlines!"

imho that's why the Hydroptere story is just so damn impressive



(*) apologies for comparing a sport using a renewable energy, the wind, with a sport requiring a non-renewable energy. And apologies for comparing a windsurfer to a F1 car. But it was for the good cause (I think) ;-)
hey antoineb,
i really like your comparison to motorsports, but looking at the different characteristics of the two types of craft i can't see the resemblance of a F1 car and the team and money behind it and a windsurfer. i also struggle with seeing a rally car in l'Hydroptere.

if anything i would say a windsurfer and its size and limited sail carrying capability looks to me more like a 250cc motorbike from the local bike shop in town for a few grand [like a local windsurf shop where you can actually buy the rigs and boards to go record breaking fast off the shelf] with a few custom parts thrown in bought from the internet [like my C3fins up to last year]. then they stripped everything away and tuned the bike to go as fast as possible in a straight line for a short stint [speed sailing]. making it lighter and less draggy as they can't increase the engine size due to the small frame [the geometric limitation of righting moment].
but the bike can still be easily fitted with other shocks and tires and be taken out for session of supercross with huge jumps [wavesailing] or motocross racing [open ocean slalom].

the only thing that springs to mind when looking for a comparison for l'Hydroptere is a monstertruck on steroids that has been built for long distance dessert crossing.
a huge solid frame to take the beating of the terrain with two huge turbocharged V8 bigblocks.
it is indeed amazing that they are so close in performance on the shorter distances to the little bikes. the little bike can't compete on long distance racing though as the tank is way too small.

but where does that leave Macquarie Innovation? maybe a purpose built dragster that has to be towed back to the start every single run, highly tuned with huge potential, but not reliable enough to last the run under full load.

the only comparison in yachting to F1 would be imo the AC with it's huge budgets and big teams. what a bummer for speed sailing though, as i don't even dare to imagine what would be possible with those resources and man power if they wouldn't have their current race format and rules for the class of boats...

i haven't found any comparison for the kites yet...

cheers
boogie
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  #66  
Old 04-18-2007, 09:42 AM
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boogie boogie is offline
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Quote:
Originally Posted by antoineb View Post
on Sailrocket:
However if you look at their design, it is basically a windsurfer, with a bigger sail, and a LOT of drag added.
i strongly disagree here. if anything then Sailrocket resembles a kitesurfer.
a windsurfer generates the necessary righting moment to balance the power of the sail by moving the centre of gravity to windward and holding the unstayed rig which is attached directly by a link to the craft he stands on.
the weight and size of the rider and the necessary geometric limitations to make it a windsurfer are severely limiting the power he can generate.

Sailrocket is a no heeling moment configuration where the power of the sail is directly balanced by the power of the submerged foil. weight and size of the rider and to some extent the craft itself other than main foil and sail has nothing to do with how much power they can generate.
when it is up and going you could take the beam and float under the wing away and it should still sail...
reducing Sailrocket to the bare minimal parts when going in a balanced state would resemble imo a sit down kite surfer with the kite or flying wing directly attached to the craft.

i totally agree with the last part of your statement though that they have added a lot of unnecessary weight and drag, but i will refrain from any judgement on the possible peak performance, as i don't really know enough details. they got a long way to go though....

it's cool to see so many projects out there right now chasing after the big five-oh over 500m.

boogie
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  #67  
Old 04-20-2007, 03:55 PM
antoineb antoineb is offline
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you're right boogie

yes true Sailrocket does not have the righting moment (potential) issue of a windsurfer - or at any rate, a much smaller issue (though when a windsurfer has an enormously inclined rig the difference is not so big imho).

so in theory, IF you don't have too much drag, and IF nothing breaks, and IF indeed you face no righting moment issue, then yes you could go faster.

personally however it still seems to me that there is too much drag on sailrocket (at least for the time being, and I know they're still working a lot on the development of the planing surfaces) and I just wouldn't put a lot of my money on them reaching 40-plus. i can only hope they'll prove me wrong.

I look back at a "simple" catamaran such as Techniques Avancees (which held the record in its category around 42 knots) before Hydroptere took it recently. This thing although being a very traditional design (depending on how far one takes "traditional" ;-), did well because of great aerodynamics, and little hydrodynamic drag.

again, I can only hope that sailrocket will prove me wrong.
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  #68  
Old 04-20-2007, 04:03 PM
antoineb antoineb is offline
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some hints on more potential for Hydroptère

I went through some of the more recent interviews of Thébault (the project manager) after their recent record on the mile.

Bottom-line is that he says things like:
- "we don't know where the limits are"
- "44.5 knots (their 500m record in their class) is nice, but clearly we can do a good deal better than that"
- "our engineers are ok to let us go over 50 if we can" (talking about stress loads)
- "50 we can do for sure as an instant speed. But doing it on 500m would require top speeds around 52 and this I am not sure we can achieve"
- "we'll go for ocean records first"

He was also asked about the modifications on Hydroptere V5 and he said the new pods "bounced" very successfully on the waves (the earlier classical pods would plant into the waves and stop the craft, leading to injuries to the craft and/or crew). He added than when doing 45 knots and such "bounces" happened, the stress loads measured on the beams were up to 60 tons (i.e. over 10x the mass of the craft). Geez.

Anyway based on this additional info i'll repeat what I wrote earlier, i.e. that Hydropère may have the potential to get close enough to 48.7, but they may not try for it before they have tried some ocean going records first.
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  #69  
Old 04-21-2007, 06:15 PM
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boogie boogie is offline
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Quote:
Originally Posted by antoineb View Post
yes true Sailrocket does not have the righting moment (potential) issue of a windsurfer - or at any rate, a much smaller issue (though when a windsurfer has an enormously inclined rig the difference is not so big imho).
hi antoineb,
i think you mightbe over-estimating the rig inclination to windward on a windsurfer on a speed strip. yes, the sails have a lot of rake/sweep, but they are actually not that much raked to windward when at full speed.
the inclination to windward is more used on light wind course racing [formula class] or when getting planing to take load off the board.

here is a series of pictures taken at West Kirby, where they had a very fast session in january. Martin van Meurs [sail# 62] had a peak speed of 49.2kn in that session.
http://picasaweb.google.com/C3carbon/Windsurf
http://www.gps-speedsurfing.com/gps....l=14163&uid=77

cheers
boogie
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  #70  
Old 04-23-2007, 08:19 AM
antoineb antoineb is offline
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thanks boogie, very interesting

probably given my modest windsurfing skills and my lack of any personal experience windsurfing at high speed I had clearly way overestimated rig inclination to windward.

thanks for the photos, and i also searched for some videos on YouTube and it can pretty clearly be seen that the rig is nearly vertical, with mast flexibility doing a lot to avoid overloading. Thanks again your post has led me to become smarter i.e. less ignorant.

in that sense yes the Sail Rocket design is quite different: (1) rigid wing; (2) fixed point at top of wing so no dampening effect to be expected from rig.

Whether the additional potential power from this, will be enough to offset the fact that this craft really looks a bit, drag-wise, like a windsurfer with a (heavy) side-car, remains to be seen in my view. My max speed guesstimate for the craft (best case 40 knots) is based on this, admittedly very superficial, analysis.

but as I've said before: this is still not exact science, and these guys are just likeable because of the artisan dimension of their attempt, so at least at the emotional level one cannot help but wish for them to reach 40 so that they see some well-deserved reward for their efforts.
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  #71  
Old 04-23-2007, 09:34 AM
AleX`G AleX`G is offline
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Wow ive only just sen hydroptere site and i can honsetly say that its the best thing ive seen come out of france in a while(meant in a good way ). I mean windsurfers are all well and good but this thing is like a proper boat. Truely a very cool boat.

Alex
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  #72  
Old 04-23-2007, 12:45 PM
RatliffFranklin RatliffFranklin is offline
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Rules and Records

Record attempts are valid on their own merits. Rules cannot make a valid record invalid or a meaningless record meaningful.

The only purpose of rules in record attempts is to establish a baseline for measuring performance so that the real degree of progress can be gauged.

The technical progress demonstrated by the Hydroptere's performance is a record in the truest sense, valid on its own terms.
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  #73  
Old 04-23-2007, 01:00 PM
RatliffFranklin RatliffFranklin is offline
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Rules and Records

Quote:
Originally Posted by boogie View Post
Doug.
a "real record" needs to be according to the rules of how to set records or they are not real records... just extraordinary performances.

i guess you have not really been closely involved in any speed sailing project that has gone past 40kn. otherwise you would never say that "55 is looking good" because of one peak speed of 46.5kn. every single knot faster after you have reached the 40kn mark is ten times more difficult to achieve and everything past 45kn another ten times harder than that. not talking peak speeds here, btw.

boogie
Extraordinary performances ARE the real records.

Thinking of "Records" in terms of meeting bureaucratic rules misses the point.

It is not rules that make a record valid or meaningful. It is progress and performance. Rules cannot make a meaningful record meaningless or provide a point to a pointless "Record." The only real purpose of rules is to establish a baseline for determining performance so that the degree of progress can be measured.
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  #74  
Old 04-23-2007, 05:15 PM
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boogie boogie is offline
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Quote:
Originally Posted by RatliffFranklin View Post
Extraordinary performances ARE the real records.
based on whose judgement?
you will most cetainly need an extraordinary performance to break a record, but that doesn't mean every extraordinary performce is a new record in its own right.

Quote:
Thinking of "Records" in terms of meeting bureaucratic rules misses the point.
i don't get it.... what point?

Quote:
It is not rules that make a record valid or meaningful.
i partly disagree. only the rules make a record valid, but not necesarily meaningful, what ever that means.
without the rules it's just an anecdotal pissing contest. "my buddy who was watching me said i was definitely going 60knots... that's a new record!!"
the ******** stops when the data drops. and when it comes to "official" records, they get really picky on the quality of that data too.

Quote:
It is progress and performance. Rules cannot make a meaningful record meaningless or provide a point to a pointless "Record."
sooooo? what's your point again?

Quote:
The only real purpose of rules is to establish a baseline for determining performance so that the degree of progress can be measured.
EXACTLY!!!

is that just me or is your last sentence saying the opposite to all the points you make before...?

don't get it.
boogie
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  #75  
Old 04-24-2007, 12:52 PM
RatliffFranklin RatliffFranklin is offline
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Rules

Quote:
Originally Posted by boogie View Post
based on whose judgement?
you will most cetainly need an extraordinary performance to break a record, but that doesn't mean every extraordinary performce is a new record in its own right.


i don't get it.... what point?


i partly disagree. only the rules make a record valid, but not necesarily meaningful, what ever that means.
without the rules it's just an anecdotal pissing contest. "my buddy who was watching me said i was definitely going 60knots... that's a new record!!"
the ******** stops when the data drops. and when it comes to "official" records, they get really picky on the quality of that data too.


sooooo? what's your point again?


EXACTLY!!!

is that just me or is your last sentence saying the opposite to all the points you make before...?

don't get it.
boogie
It's analogous to the concept that human rights are inherent to the individual and so are not up to governments to grant but only take away.

Rules don't make records. They only provide a baseline for measuring the accomplishment.

For example, the fact the first fifteen World Land Speed Records were one-way runs while many of the later two-way runs only allowed a half hour instead of an hour turnaround time doesn't make them any less valid as a benchmark for the technology of the time.
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