staysail

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About staysail

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  1. staysail

    Vendee Globe 2020

    All that aside, it would be interesting to see a photo of the leading edge of Arkea's foil.
  2. staysail

    Vendee Globe 2020

    Went fishing, caught 2! Ha ha!
  3. staysail

    Vendee Globe 2020

    Radical greens don't understand anything. That is the problem with them.
  4. staysail

    Vendee Globe 2020

    I suggest the actual functioning and hence design of an Imoca foil is still in a very experimental phase, otherwise why would there be radically different types out there? When you consider the foil is almost never fully immersed and is moving through waves and wave tops in which individual "lumps" of water are moving in all directions, (quite fast in big waves) and the foil itself is both ventilating and possibly cavitating over parts of the surfaces almost all the time, you have a fluid/solid interaction situation which is near-impossible to define in mathematical terms, let alone finding any ideal solutions. It is old fashioned R & D with a sprinkling of science. Foils work, and by trial and error and experimentation people are learning how to design and make better ones all the time. As for having a full understanding of how they work, that is another matter altogether. For the Imocas and for the Vendee Globe in particular, foils represent progress. They have made the boats significantly faster and have added a degree of glamour and much technical interest. Contrary to many peoples expectations (including mine I confess) they have not been the cause of higher attrition. One of the most severe races in terms of percentage finishers was 2008/9 before foils. Quite a few foils have broken, but up until now foils have never caused catastrophic boat failure on an Imoca and the jury is out on that one for PRB this time. It will be hard to prove anyway assuming the bits of PRB are beyond hope of recovery. As far as the race is concerned foils are a success and just go to prove that innovation leading to increased speed is win win for a technical sport. Any lightweight fast raceboat can be broken sailing hard in severe sea conditions. That is why some competitors have sailed less aggressively than others, knowing that there is a long way yet to go. I have noticed several boats in this VG going relatively slowly in this race compared with speeds which they have been making in earlier shorter Imoca races this year in similar wind conditions and boat preservation rather than an inability to go fast is obviously the reason.
  5. staysail

    Vendee Globe 2020

    Yep, but crossed the line in 3rd a day ahead of the next one.
  6. staysail

    Vendee Globe 2020

    The same boat became Roxy and crossed the line 3rd in the 2008/9 race.
  7. staysail

    Vendee Globe 2020

    In the last VG Romain Attanasio broke both his rudders (fixed type, not kick up) and had one spare which he swopped out by going for a swim and he carried out a repair on the second and finished the race in a respectable place. The challenge Alex faces might be less severe?
  8. staysail

    Vendee Globe 2020

    Get a life!
  9. staysail

    Vendee Globe 2020

    Yes, without a fully accurate FE model it is not really possible to come to any meaningful conclusions about the damage. All this does is illustrate to the layman that FE analysis is a technique which exists. ATR will very likely have used it when designing the structure and will have known both the real scantlings, the actual materials properties and they will have input the loadings to their best estimates. If the analysis was competent which it probably was, then the longitudinal structure with the obviously broken parts has been overstrained massively beyond the design safety factors which I would assume would be intended to keep everything below the material elastic limits by some order of magnitude. In short, if the boat was damaged by slamming only, the slamming impacts which caused the damage were greater than ATR expected by a very large margin. The interesting thing to consider is that if Alex was able to give a very precise description of the cracks the ATR engineers could make a good guess as to what the fracture strains (and implied stresses) actually were when the boat failed. They could then apply these new much higher strains into the existing FE model and back-calculate what loads caused them. These being quite close to those they should actually have designed the hull for, (before applying a safety factor) so it would not have broken. The unfortunate side of this reasoning is that if they apply much higher loads (which they now know to be "realistic") to their FE computer model they will probably find out that many other parts of the boat will be severely overloaded by them, and the only safe way to continue sailing is at greatly reduced speeds.
  10. staysail

    Vendee Globe 2020

    Do you suppose his team have done a full FEA on the repaired structure and prounounced it safe for a high speed Southern Ocean trip in the world's most remote region?
  11. staysail

    Vendee Globe 2020

    I guess he has enough food to get to Cape Town.
  12. staysail

    Vendee Globe 2020

    If he knows anything about structural design and if that lot has failed like that without the boat hitting anything solid Alex will be a very brave man if he sails it hard in the Southern Ocean after performing any kind of repair. Lets wait and see how fast he goes after he has given it all time enogh to fully cure. Hats off to the HB project for allowing that video to be made public.
  13. staysail

    Vendee Globe 2020

    We folk onshore can really have no idea about the cause of the problem however. If it is really a "structural issue" as opposed to damage from hitting an object in the water, the "fix" is not likely to be an "easy" one! If the hull structure did not have manufacturing defects or errors (unlikely?) and the design has proved unable to withstand the slamming experienced during only a small fraction of the total racing time, logically it is not just a repair which is needed. It is a reinforcement operation, otherwise it needs to be sailed less aggressively. The race is still in its early stages and boats will have a lot more slamming to withstand before they get back to Les Sables. The VG is known for being a war of attrition.
  14. staysail

    Vendee Globe 2020

    3 hours between updates is a long time. Might as well chat about something vaguely relevant?
  15. staysail

    Vendee Globe 2020

    AT fanboys are sure optimistic! Lead over Linked out cut to 22.3nm but we are sure it is all good news and in the plan.