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MartinRF

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Everything posted by MartinRF

  1. 80 days? How long would it take a log in the Gulf Stream? (The log would be swept north of the UK, I think) /Martin
  2. Rotating mast solution: http://hem.bredband.net/b262106/pages/launching/index.html (scroll down to mid-page) Dolphin striker for alu tube: http://hem.bredband.net/b262106/images/old_dolphin_striker.png I don't think rotating/non-rotating is important for mast base loads. Sail-mastbend interaction is another cup of tea though. /Martin
  3. 8:1 and no winches sounds way too little to me. http://hem.bredband.net/b262106/pages/controls/index.html I see no running backstays so the main sheet is what tensions the fore stay. Are your sails of stout enough material? My first set of sails were underbuilt dacron things (1986) and de-formed badly as the wind picked up. Reefing the main was more about controling shape to be able to point rather than avoiding capsize. These days I don't have this problem thanks to the wonders of modern materials. My lee shroud goes real floppy but as long as I haul in my main sheet the fore stay
  4. Their own wep page: http://rowandsail.liteboat.fr/boats/litexp/ /Martin
  5. Sorry for stepping in so late. I have been traveling... My view on foil sections is that choosing a proper foil section is not only for racing guys adding a fraction of a knot in speed but for everyone getting better, more reliable steering (talking rudders now). Pretty much any proper foil section is better than the foil section look-a-likes many boats come with. They are less prone to stall or suck down air. Preventing this is more important that minimising section drag. Control trumps low drag in real life and section drag is such a small part of the total drag anyway. Our aspect ratios
  6. Never heard of Tefgel before. I have used the black, thick stuff used in Scandinavia to protect car under-sides against corrosion. It is cheap and has worked just fine for me. A car safety inspection guy told me the other year lindseed oil does the job. I have not tried it. Then something like Molykote P-40 might be worth investigating. https://www.lubricantspecialty.com/product/molykote-p-40-paste In the assembly manual for the M32 cat, Aston Harald recommends Molykote 1000 for the beam bolts. This is a different application though: stainless steel bolts in all cabon beams and hulls.
  7. Not 15 minutes. He has been doing these media stunts since the 1970s. Mostly not even putting to sea at all. /Martin
  8. "Catamarans Offshore" by Rudy Choy is a good read about all this if you can get your hands on a copy. https://www.amazon.co.uk/CATAMARANS-OFFSHORE-Rudy-CHOY/dp/B0006C5368/ref=sr_1_1?s=books&ie=UTF8&qid=1531039935&sr=1-1&keywords=Rudy+Choy /Martin
  9. Judging mast bend from that photo may be tricky. There is a 100 mm pre-bend set-up by help of swept spreaders and diamond tension and the mast is rotated beach-cat style. Here is another photo in similar wind but as we were sailing two-up I could sit on the windward bow while shooting this. Still not a great photo but I think the mast-top bending windward-and-aft can be seen. This what it does when the mast is fully rotated and the main sheet is fully in. If I reduce mast rotation the top will start to fall off to leeward and the pre-bend lines up with the sail 'cloth'. Both these an
  10. Not boatbuilding either but very definitely carbon fibre layup automated: /Martin
  11. Some racing multis, mostly French ones, cant their rig to windward but the rest of us don't bother with that as complication and cost goes through the roof. As things (shrouds, crossbeams...) have limited stiffness our rigs lean over to leeward instead and the lee shroud goes limp. In my case it is very limp: I have not thought much about this untill last weekend. This morning I tried to find photos I could use for measurement but only found a couple and all with me singlehandling (= low stability). The one above is the best since I am just about to fly a hull (in a guestimated 10
  12. I have met this guy. Being an oddball is what he likes to do. It is his trade mark. He even changed his name to reflect this. Back in the 1970s he actually did som serious sailing in a 20' boat he had built in his mother's basement. Just found his web: http://46.28.145.175/?page_id=4593 This nice cold-molded little thing with poor stability took him to the south atlantic and to fame. (His web claims Bris was his first boat but there was a small steel ship convterted to sailboat called Duga before that. I guess he is not keen on reminding the world about that boat as it sank -- to get ins
  13. Is this the tri I think it is, the green one that got two new hulls some years ago? https://youtu.be/dMqYkGEmoF0 /Martin
  14. I don't know about crazy, colourful maybe. Yes, I have met him, he lives (lived maybe because it has been a while) nearby. No, I don't know for sure what speeds he has achieved but it is faster than 'normal' ice yachts -- superior aerodynamics. He also develope compasses designed to help racers -- for classes not allowing electronics. These guys also live nearby (and the Trampofoils were developed in a workshop I use for tinkering with parts of my boat). https://www.youtube.com/watch?v=QQvYogFP9mw /Martin /Martin
  15. Some can't wait: /Martin
  16. Last weekend: Turning around: Some other examples (different years): https://get.google.com/albumarchive/103341501341482571816/album/AF1QipNO2At8uQOMcPkCsXO-GU24ME8ynUiGu0JgbDz6/AF1QipOB91dIq0F4t_3qMNLRmsGSfGKBUCOO4AD950cq https://get.google.com/albumarchive/103341501341482571816/album/AF1QipNO2At8uQOMcPkCsXO-GU24ME8ynUiGu0JgbDz6/AF1QipP8dRqlC1uenSbsDP2CtXQTDYOyt5KsA-lUjIyL https://get.google.com/albumarchive/103341501341482571816/album/AF1QipNO2At8uQOMcPkCsXO-GU24ME8ynUiGu0JgbDz6/AF1QipNfx_5M0dN6bcjL55h1VX-FHKy0k_vUicSbSm2k /Martin
  17. Re sleeving, here is a summary of work I did to help a Belgian Spyder owner. /Martin Spybeam.pdf
  18. I had this problem when my Spyder was almost new. We didn't crack the forebeam. We 'only' bent it -- beafed it up and then bent it again. Other Spyders in Europe have broken beams so clearly a weak point with this design. In 1989 I re-engineered the crossbeams from the ground up together with a friend and that was that. /Martin
  19. Not new. A German aerodynamics professor came up with this in the 1960s (I think) but he was doing it on trimarans that were actually built and marketed. I should remember the name of the professor but I don't I think the trimaran brand was called Sigma. In the 1970s a guy in my native Gothenburg did it to his own Telstar trimaran. In his case the rig was fixed but the side hulls were hinged in a spring-loaded way that allowed the boat to stand up to the wind up to pre-defined load level. Me and my brother joined him to test the system on a windy day. The boat was heavy and leaning ove
  20. I was actually thinking about racers in general not only the ones in VOR. /Martin
  21. Two old (August 1990) photos by a newspaper photografer and two recent photos. The last featuring a becalmed F22. /Martin
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