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507 F'n Saint

About weightless

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  1. Maybe this is particular to aluminum drums? I inspected my Lewmar 48's which are not aligned in the Harken way. They've been used as hard as I can use them. Grinding the jib home when powered up I stand over the winches and lean hard into double handles at low speed. I can't see damage to any of the teeth on the drum or the drive gear.
  2. Yes, without MPPT a 72 series cell panel connected to a 12 volt battery will be woefully inefficient. I suppose if I understand Victron Energy's analysis then in hot climates it makes sense to go as parallel as possible with the cells and skip the overhead of MPPT. I think that more parallel cells is better anywhere you have significant partial shading, too. I suspect that when shaded by rigging on a sailboat in the tropics a 72S panel on a MPPT might be less efficient than a 36S x 2P panel on a simple protection / charge controller circuit. On the other hand, panels mounted in unobstruct
  3. Does three paragraphs count as a manual?
  4. Programs here -- you can't tell the players without a program! https://www.lewmar.com/node/11530 I don't quite get the question. Is it about the orientation of the winch base and wear? It's not like I know anything about it but it'd be news to me if the orientation makes a difference to the longevity. Or was the "whooshing" noise the point flying over me again?
  5. I was shocked -- figuratively -- to discover that many boost packs are three series cell lithium-cobalt batteries. 3S li-ion is not a good match with lead-acid. If I was considering a lithium backup or starting battery I'd look at a 4 cell lifepo4. Safety aside, lifepo4 is a better match with lead acid.
  6. Maybe powerpole or similar connectors on the extra battery? You can get caps for them and they should be a bit less likely to cause random welding events. Edit: Looks like Egon beat me to it.
  7. Maybe a wooden dowel in place of the pin would rattle less annoyingly? Counter bore a bit on the holes in the plate and a put an o-ring on at the bottom of the pin that fits in the counters? Dubious solutions to a non-problem, no doubt. I have an unlimited supply of those.
  8. That's neat. I wonder if making the pin a bit conical would take the rattle out?
  9. Modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a separate signal called the modulation signal that typically contains information to be transmitted. ... The carrier is higher in frequency than the modulation signal. The purpose of modulation is to impress the information on the carrier wave, which is used to carry the information to another location. Synonyms for insobriety excess, excessiveness, exorbitance,
  10. From the disdain for cutting the excess from the mast foot I take it this not a cunning plan to reduce the mass moment of inertia?
  11. I noticed this doc from Victron today: https://www.victronenergy.com/upload/documents/Technical-Information-Which-solar-charge-controller-PWM-or-MPPT.pdf This quote right at the top stood out to me: "It is generally accepted that MPPT will outperform PWM in a cold to temperate climate, while both controllers will show approximately the same performance in a subtropical to tropical climate." It seems like a worthwhile read for anyone in the market. FWIW, I think they give MTTP every benefit of the doubt and for "PWM" [sic] they assume the worst. There's a fair bit of neglect
  12. Could be. It was just the first hit from google for "sail power calculator". There should be others and they may meet your needs better. IIRC, Larsson and Eliasson's Principles of Yacht Design has all that's needed to code up your own.
  13. Folks have coded the calcs for guesstimates of sail force and moment. eg. https://cdn2.hubspot.net/hub/209338/news/SailPowerCalc/SailPowerCalc.htm You could play around with your numbers in one of them.
  14. That does take some of the edge off of the weeping and gnashing of teeth, dunnit?
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