southerncross
Super Anarchist
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VOR 2017-18
- Thread starter JeronimoII
- Start date
jbc
Anarchist
Another cool video on navigation challenges in the Fastnet, this one from Jules Salter of AkzoNobel:
Francis Vaughan
Super Anarchist
I am far from the best person to ask or trust an answer from. As already pointed out above, polars from a sail manufacturer are at best a first round approximation. But perhaps the most important part that the sail maker can't provide really useful guidance on are the cross-overs. There is no substitute for working these out on the boat.
The problem with rig loads is that you aren't worried about static loads. Sure, you could get a simple approximation to much of the rig load from the sail design. That already forms part of the sail's design. But the dynamic loads are way out of the control of the sail designer. That is where judgement and the instrumentation of the rig comes in. All of these boats carry rig tension instrumentation, that is intended to provide guidance. But even then it can only tell you that the last slam took you into the red zone. Judgement is needed to decide whether the next slam is going to take your rig past its limit.
Hitchhiker
Hoopy Frood
Retired Sailor
Member
Thanks for taking the time to reply Francis. If they have rig tension information wouldn't that show up potentially damaging loadings. As a simple example, repeated differences in loads in the windward components relative to one another (caps, and the intermediates to the roots of each successive spreader etc.), and the same in the leeward components. What I am trying to get at is whether there is a way DFRT or Mapfre could have known there was a problem before it happened. Maybe there was loading information but it wasn't collated and presented in a readily understandable form (e.g. stress at the upper starboard spreader repeatedly red zone!). I was surprised by the sail configuration that DFRT used that caused the problem (a masthead with a reefed main), but their speed polars presumably showed that it worked, otherwise they wouldn't have used it so much. And even North admitted that the boat was underpowered if they dropped down to the V1.
Hi Bucc, the reason DFRT came fourth was a mistake / clusterfuck on a sailchange as they reentered the Solent. That took the from a close second to fourth. No lack of heart, no lack of 'sailing in the moment's. Just bad luck at an important part of the race.
Obviously you have no way of knowing this, as it was not reported. Out of interest, would you think they have a lack of heart if they had finished second?
Francis Vaughan
Super Anarchist
The VO65 has, AFAIK load cells on the chain plates and maybe forestay. No idea about backstay. Since the backstays have jumpers, it gets quite messy to work out what the precise loads on the mast are. It was indicated that they don't have the level of instrumentation that was common on the VO70. The problem with mast tube failures is that you don't really get a good idea of where the anomalous loads are just by looking at rig tensions. You can get an indication that the dynamic loads are getting higher as you drive the boat, but you can't really have any sort of absolute information. DFRT's mast failed due to deliberately applied loads bending the mast. A load cell at the mast step might have helped, but they really knew what they were doing, and had been warned they were outside the design regime for the mast. So they were not blind to what they were doing. Indeed, they knew the static strain the mast was under, as they had deliberately acted to put it there. The failure of the mast track bonding was predictable with that strain, and the failure of the mast tube not a huge step further. But carbon is a messy beast to predict and short of high tech tricks like bonding strain gauge wires into the layup of the mast, knowing exactly what was happening would have been difficult. But SS knew the tube had not been designed for that loading. And they told DFRT. All they get on the boat when driving are a set of warning lights that tell the helmsman they hit the red zone. Little more than a "please back off" warning. Trouble with those is they become a target, and a helmsman might decide to drive hard enough to just have the lights flickering on.
If you think about the loads on the rig during slamming there is a lot going on. There are resonant modes in the rig, and these can act to create ridiculous peak loads when the entire boat slams Predicting just what is going on from simple rig tension would need a medium sized supercomputer to run the model, and it would probably still get it wrong. Throwing a few dozen load cells at the rig might help. But even then, you can't stop deliberate misuse. The regime of "we have got away with it so far, so we should be OK to keep doing it" is a common problem. It is what resulted in the loss of two Space Shuttles, and a host of other catastrophes. This is where real experience come in.
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Rennmaus
Super Anarchist
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www.rolexfastnetrace.com and its tracker crashed.
Live stream is at least here: https://www.facebook.com/pg/RoyalOceanRacingClub/videos/?ref=page_internal
Live stream is at least here: https://www.facebook.com/pg/RoyalOceanRacingClub/videos/?ref=page_internal
bucc5062
Super Anarchist
No, I think they have heart, they have passion, and having lost races due to "things going wrong", I can feel for them.
Perhaps I said it wrong and I apologize for that. How they are presented in public, I just don't connect with them. That's it. As I said, I respect the hell out of all the sailors in this race, except one.
Now, is anyone else locked out of the fastnet website?
bucc5062
Super Anarchist
DtM
Super Anarchist
RS, you are incredible and so unrealistic it is scary. Bucc, you are little better.
Each wave creates different loads and these guys and girls are racing as hard as they can. Staring at gauges all the time is not what this is about. Anyway, what the gauges tell you, just like wind instruments, is what happened. It is passed and gone, you survived.
Some of what happens is calculated (no not from gauges but from years and 1000's of miles of experience) risk. Very very occasionally there is a miscalculation or mishap.
Anything the two of you have thought of the brains in all of the teams thought of and either put into practice or discarded years ago on this or another programme.
Each wave creates different loads and these guys and girls are racing as hard as they can. Staring at gauges all the time is not what this is about. Anyway, what the gauges tell you, just like wind instruments, is what happened. It is passed and gone, you survived.
Some of what happens is calculated (no not from gauges but from years and 1000's of miles of experience) risk. Very very occasionally there is a miscalculation or mishap.
Anything the two of you have thought of the brains in all of the teams thought of and either put into practice or discarded years ago on this or another programme.
bucc5062
Super Anarchist
First time watching this and I have to say the media presentation is pretty damn good. Getting excited for the IRC0 and VO65 start.
Rennmaus
Super Anarchist
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shanghaisailor
Super Anarchist
He He - I have to laugh at some of the uninformed comments on the forum.
In the last race DFRT were criticised for 4 sail reaching and now Mapfre are being praised for it - make your minds up guys.
But the comment by Bucc that Dongfeng had no heart had me falling off my chair and to follow up with the "fact" they could have passed Mapfre in the RTIOW sprint an didn't because they "have no heart". It was a practice race my dear boy, they were pacing Mapfre so took the opportunity to try a couple of things to see if it was faster or slower - it was slower. This is part of Leg 0, the real stuff starts in October.
The Fastnet Race is a bit different and already it is DFRT & Mapfre that appear to be the front runners but only just. It will be interesting to see the positions when I wake up in the morning (close to midnight race time when the first tidal gate will have been negotiated and the tide will have turned (and turned back) or maybe Dee's Southerly position will pay off further out into the channel - who knows.
Don't you remember the footage of Charles thumping the wheel or jumping down onto the cockpit floor in the last race, or the efforts he made to learn enough Chinese to say the right thing when they got to the stage in Sanya?
Mo Heart - that's so funny.
SS
In the last race DFRT were criticised for 4 sail reaching and now Mapfre are being praised for it - make your minds up guys.
But the comment by Bucc that Dongfeng had no heart had me falling off my chair and to follow up with the "fact" they could have passed Mapfre in the RTIOW sprint an didn't because they "have no heart". It was a practice race my dear boy, they were pacing Mapfre so took the opportunity to try a couple of things to see if it was faster or slower - it was slower. This is part of Leg 0, the real stuff starts in October.
The Fastnet Race is a bit different and already it is DFRT & Mapfre that appear to be the front runners but only just. It will be interesting to see the positions when I wake up in the morning (close to midnight race time when the first tidal gate will have been negotiated and the tide will have turned (and turned back) or maybe Dee's Southerly position will pay off further out into the channel - who knows.
Don't you remember the footage of Charles thumping the wheel or jumping down onto the cockpit floor in the last race, or the efforts he made to learn enough Chinese to say the right thing when they got to the stage in Sanya?
Mo Heart - that's so funny.
SS
bucc5062
Super Anarchist
Okay, I did clarify so can you at least acknowledge that. I didn't word it right initially and good lord, we all have favorites. How they are presented, the public face...I don't connect to the team in the same as others, as you and since perception for many comes from what we see, I see a hell of a well sailed boat, yes I remember Black and Horace, but it took a long time for that story to emerge.
Maybe it is the french way. Following the VG it was much easier to cheer for HB, Coleman, a couple others, because I could relate in some way. The front runner not so much. Not questioning his ability to sail, but his ability to connect to the crowd.
I've said my mea culpa, agree with everything you said, but my heart is for TToP and Askonobel and those two I hope do well. They are hanging tough right now.
bucc5062
Super Anarchist
That's an interesting take. Would any team? How much is at stake, image wise, vs what you learn playing. Aknobel talked about throwing all kinds of sail plans up for the next "race" so perhaps none of them are taking it serious as a "gotta win". I just saw that Mapfre tacked over and yb has them as leader so at what point to you stop testing and start hitting the pedal. It is a level of sophistication above my scale for when I raced, I didn't hold back.
At last check the spread front to back was @ 1.3 miles so if DF is pushing harder this time, so too is everyone else. As a side note, Mapfre AIS is not sending for I can see the other six and it seems yb is slightly behind Marinetraffic (I see DF and AKN have now tacked) and Brunel and TToP remain heading out. Certainly not all playing follow the leader
Francis Vaughan
Super Anarchist
Nobody gains anything by winning this race except a bit of a bit of sponsor glory (which isn't to be sneezed at.)
But these races are the first time the boats have come together. Tactically, learning everything you can sailing in the fleet has to be top priority. Minimally you have a chance to see how your setups are working against the other boats. Which of course cuts both ways. But you would want to be pretty confident about how good you were to be sandbagging. You stifle your own ability to learn.
Some teams are going to be learning fast, as the latecomers are still getting to grips with the boat and their crew. There are times when every team will want to push as hard as they can, as they will be learning when they do. And there will be other times when it makes more sense to look about them, and pace things accordingly, and learn other things.
I'm sure that winning is something everyone wants, and they will all be in race mode. But at this early stage, I would hope that the broader picture would dominate thinking.
But these races are the first time the boats have come together. Tactically, learning everything you can sailing in the fleet has to be top priority. Minimally you have a chance to see how your setups are working against the other boats. Which of course cuts both ways. But you would want to be pretty confident about how good you were to be sandbagging. You stifle your own ability to learn.
Some teams are going to be learning fast, as the latecomers are still getting to grips with the boat and their crew. There are times when every team will want to push as hard as they can, as they will be learning when they do. And there will be other times when it makes more sense to look about them, and pace things accordingly, and learn other things.
I'm sure that winning is something everyone wants, and they will all be in race mode. But at this early stage, I would hope that the broader picture would dominate thinking.
jbc
Anarchist
Hm. Turn the Tide on Plastic appears to be off the back of the group in the tracker. Did something happen to them?
Eh; I just updated and they're looking a lot closer. I think it's probably just a combination of them being toward the back (which is understandable, given their program at this point) and the tracker updates being staggered/laggy:
Eh; I just updated and they're looking a lot closer. I think it's probably just a combination of them being toward the back (which is understandable, given their program at this point) and the tracker updates being staggered/laggy:
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Hitchhiker
Hoopy Frood
I can't seem to get onto the Fastnet page or tracker, now. Anyone else having an issue?
