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About MartinRF

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    Stockholm, Sweden

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  1. Off-loading the board is what I do: a quick bear-away synchronized with pulling the board up. Slowing down is safer though. /Martin
  2. I use nothing. The trick is to realize there is no need for a very tight fit and apart from the exit hole in the bottom of the hull the fit can be quite sloppy. For support higher up in the dagger board case you can use synthetic carpet material or astroturf to take up the slop and avoid noise. I use this both top and bottom in my rudder sleeves. Adding a wear protecting 'rail' (my English failed me) to the rear of the dagger board case is nice as that edge of the board can be a bit 'aggressive'. Rudder sleeve seen here: http://hem.bredband.net/b262106/pages/index.html /Mar
  3. On smaller cats with accommodation in the hulls the presence of a dagger board case is a serious obstacle. Hence it is angle one way or the other to get it out of the way. This means there is a vertical force component when sailing. The other day I amused myself by making an approximate drawing of my boat and calculating the forces: The green arrangement is what I have on my boat. Ease of handling is an obvious advantage. The numbers show a non-trivial increase in righting moment for the red arrangement and it is for free (I think) -- a compelling argument for the red version.
  4. This guys is testing and repairing battery chargers and some other stuff. He also tests the recon function. Might be of interest: https://www.youtube.com/channel/UCxQND04oRmv_KgEpWjW0-mg /Martin
  5. "waypoint" may be too much for the uninitiated reader. I have no better suggestion. It is your language, not mine, after all. /Martin
  6. This is science click-bait. Nature (the publication) does this all the time but this time it is Science. Looking up the paper in Science I find the H2O2-treated balsa is not as strong as glass. Far from it actually. The numbers reported are lower than those of the pure epoxy resin! Glass fibres reinforce resin. In this case it is the other way around. The epoxy is AeroMarine 300/21. https://advances.sciencemag.org/content/7/5/eabd7342 https://www.aeromarineproducts.com/product/300-21-laminate-epoxy-resin-1-5-gal-kit/ /Martin
  7. 1990s Strockholm: https://youtu.be/QQvYogFP9mw 1989-90 Gothenburg: http://hem.bredband.net/mschoon/af_Chapman_II/ and MIT did something like the manta even earlier, I think. The Trampofoil guys got some free TV time at the time. They tried to go commercial but this simply too niche. In later years one of them has been involved in a foiling motorboat project with better economical backing. That project may take off (pun intended). https://candelaspeedboat.com/ /Martin
  8. MartinRF

    Boat Names

    Reminds me of "Never Again II". I don't know if this name exists outside internet fora /Martin
  9. MartinRF

    Boat Names

    Over on this side of the planet there once (1980s) was a sailboat called "Ormgas". With its original name it was banned from entering any of the regattas arranged by the Royal Yacht Club. It is not too hard to figure out the original name by rearranging the letters in "Ormgas"... In the late 1990s I came across a catamaran mentioned in a multihull rag from Australia. Its name was "LBTPASB" or "light blue touch paper and stand back". Not being a native speaker of English this was mysterious to me. What is light-blue touch paper? Eventually someone explained My own boat is named after
  10. Here is an example of a winch-less system on a boat that is slightly smaller than an Open 8.5. /Martin
  11. I have 35-ish years of experience of a fully battened mainsail (square top at that for the last 22 years) of about 30 sqm and I don't think the weight of the battens is what bothers you if you have problems hoisting your sail. I would take a look a at what I could do about friction. In my case it helps a lot to clean the luff grove of the mast. Batten pocket hardware and how the sailmaker positioned it relative to the bolt rope also plays a sigificant role. All this assumes bolt rope in luff groove. Dirt and friction are factors regardless. /Martin
  12. OK, I know this thread has been hibernating for two weeks now but I just came to think of this old dinghy description by Richard and Lilian Woods. See attached document.Crayfish__Woods_1982.pdf /Martin
  13. MartinRF

    Lithium v AGM

    I asked for the source of the efficiency figures appearing in your first post. That was all. /Martin
  14. MartinRF

    Lithium v AGM

    So the data is your own? /Martin
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