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MartinRF

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Everything posted by MartinRF

  1. Had a pair of Line 7 PVC bibs 35+ years ago. Very durable but also very heavy and clumsy. I do have a complete set of PVC, high-vizibility foul weather gear for when I know I will get dirty and don't need mobility/agility. Low cost but for standing up in bad weather rather than sailing my boat. The H-H overall I mentioned keeps me drier and offers more agility than the PVC stuff. Going for bibs + jacket is a convenience thing. /Martin
  2. Where I am now, Stockholm, Sweden, salt is not part of the environment. Apart, that is, from the salt they spread on icy roads. I have other 'breathable' all-weather gear for other types of outdoorsy activities such as my (non-pandemic) daily bicycle commute and have had no such problems until wear is rather obvious. The one disappointment was a bright blue thing from an American brand starting with the letter P. The watertight/breathable coating started flaking after two years. When I was still living on the Swedish west-coast where wind and real waves means spray (salty spray), my
  3. Yesterday's sail ended in a downpour. The good thing is I had rolled up sails and stowed them in my starboard hull before the rain started. The bad thing is I found my foul weather jacked is anything but water tight. Shoulders and arms wet to the skin in minutes. This garment is at the end of its eight season if my notes are correct. Eight seasons of very light use. There are no signs of wear and the cloth looks completely intact yet a few minutes of rain was all it took to get wet. Will washing and re-impregnating bring this thing back to form or is this the new normal for fancy, brand n
  4. When I studied electrical engineering some 40 years ago some mechanical engineer students built a ram-jet driven bicycle. Think Nazi buzz-bomb engine mated to bicycle frame. I never saw it in action but I heard it. It was VERY noisy. /Martin
  5. Navigatrix may interest you guys: https://navigatrix.net/nx/ /Martin
  6. Completely off topic but why is it named Administration Bay? There must be a story... /Martin
  7. Swedish air-force pilots did a lot of showing off when we were out on the Baltic. "Look, the navy, let's have some fun!" type of... Sub? No way. A sub being that easy to detect would be very undesirable. /Martin
  8. I did my military service in the Swedish navy. Among other things I was involved in 'de-gaussing' ships. What you do is kind of similar to erasing a tape (remember those?) but on a much larger scale: You move the ship through a strong magnetic field that is switched back and forth. The magnetic compass went berserk. It not only rotated like wild, it also stood on its end and flipped from side to side. /Martin
  9. Off-loading the board is what I do: a quick bear-away synchronized with pulling the board up. Slowing down is safer though. /Martin
  10. 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
  11. 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.
  12. 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
  13. "waypoint" may be too much for the uninitiated reader. I have no better suggestion. It is your language, not mine, after all. /Martin
  14. 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
  15. 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
  16. MartinRF

    Boat Names

    Reminds me of "Never Again II". I don't know if this name exists outside internet fora /Martin
  17. 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
  18. Here is an example of a winch-less system on a boat that is slightly smaller than an Open 8.5. /Martin
  19. 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
  20. 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
  21. MartinRF

    Lithium v AGM

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

    Lithium v AGM

    So the data is your own? /Martin
  23. This made me remember an anecdote told to me by a fellow at usenet news rec.boats when that forum was still active. My source had worked either for the U.S. Navy or the Coast Guard in southern California back in the day when hippies were a thing. One day they came across this sail boat heading straight out into the Pacific Ocean and since they were already some distance from the coast they decided to check things out. The boat was crewed by a bunch of young, bearded men claiming they were heading for Hawaii. Sure enough they had food and water to last the trip but very little navigational
  24. MartinRF

    Lithium v AGM

    Where did you get those efficiency numbers from? The reason for asking is I looked into this (for non-vehicle reasons) a few years ago and what I found then was not that high. /Martin
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