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574 F'n Saint

About weightless

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  1. Peak FUBAR? I mean, stylish and all, amiright? However, I gather, from a quick scan of the wiki, that they canceled the ammo procurement for the super fancy guns that it was designed around and that are central to its mission. There is no other ammo that can work in those guns. So, these ships can't do the mission they were designed for at all. They gave up on the fancy stealth deck house and replaced it with a steel one. So, they're not really stealthy. The electronics that they need to navigate failed when they got less than perfect power. Are they really seaworthy much less ready to be
  2. Careful now. That is well over nine and a half nano tonnes of TNT equivalent.
  3. Sounds like a plausible story to me given a perfectly still and homogeneous ocean and a container with a slow leak. Maybe not the alpha to omega of container dynamics? But whadda I know? I thought the bull and fly thing was a creation story with a new universe popping into existence at the singularity. A big bang. So called on account of where the bull was headed.
  4. Wouldn't every container that starts at positive buoyancy and ends at negative buoyancy be of "neutral buoyancy" at some point?
  5. Didn't Gary Hoyt claim that a bloated melon seed shape was ideal for slowish human powered boats?
  6. I am amazed Maybe that particular box didn't want to go to the great bit bin in the sky? If a quote box in the forum editor has accepted its fate one can delete it by backspacing over it or highlighting it and hitting delete or putting the cursor above it and hitting delete until the offending box is eradicated. I have attempted to engage them in prolonged discussions of phenomenology but so far no box has deleted itself in despair. I don't think that's best practice. Also, it's kinda cruel.
  7. I'm not the OP, I was just reiterating what I'd read of his. If the battery is going to be taken out of the boat often it might be worth connecting it with Anderson power connectors or similar.
  8. In the context of a sit-in 16 foot trimaran with just the trolling motor connected and with the battery likely taken out of the boat for charging I wouldn't expect a lot of those loads. I have this vague memory of a paper I read suggesting that the time spent charging made a difference to the number of lifetime cycles and that there was a Goldilocks zone. So, a very long charge time is bad which is why floating is bad and a very short charge time is bad which is why there's a C limit. So, maybe the battery would be "happier" on a charger that takes less time than the 5A one? However, I'd
  9. I'm completely with you there. Just to be clear, for me the question is can the DC relays we looked at be put in series as suggested by Crydom's tech note. I don't think so, but I dunno for sure. On the other hand, I don't think there is any question that a circuit can be implemented that functions like the example series circuit in the tech note. I built something related for one of my crappy solar controllers but with p-channels and not any worry about switching times. It functions at the level I needed. Making a less bad circuit wouldn't be any great trick. I suspect that making i
  10. I dunno. I put some random bits into ltspice and On drops about 300 uV across the combined fets in either polarity at 120 mA. 44mV at 24A. Off is off. No idea if that is correct or if it means anything with real world mosfet SSRs. Maybe...
  11. I think you're right. I don't know what's happening in the "trigger circuit" for the Cyrdom relays we looked at. But, I wouldn't count on it working correctly with +- reversed. However, Cyrdom put out that pdf suggesting using discrete relays in series with both relays turned on and off with the same control signal. So, maybe they make some that are appropriate.
  12. Both should be off or both should be on. Then you get two times RDS-ON with no diode drop. Both the reverse and forward biased diodes get bypassed when both are on.
  13. I think the diode is a byproduct of how mosfets are constructed. It is bypassed when the mosfet is on to get rds-on so no diode drop. Someone else drew an 8x10 color glossy picture with circles and arrows and a paragraph on the back. https://electronics.stackexchange.com/questions/389406/how-should-i-understand-the-intrinsic-body-diode-inside-a-mosfet
  14. I was thinking those were just depictions of the body diodes of the FETs. No? For sure a BMS for a big battery is a job for the pros. I'm just trying to get a high level understanding. I am stoked to have learned some things about SSRs that might be generally useful. In theory, I suppose one could make up a high current bidirection SSR with similar logic as above from discreet SSRs in series. I think there are details that will matter. While it's a bit short on specifics I found this interesting technical note from crydom: http://www.crydom.com/en/tech/newsletters/solid statemen
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