Self righting possible?

Discussion in 'Stability' started by James Wellington, Mar 31, 2022.

  1. James Wellington
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    James Wellington Junior Member

    How about self righting for these stubby fishing boats? Sometimes their lenght/ witdth ratio is 2:1. They have deep draft, lots of heavy machinery down there.
     

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  2. jehardiman
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    jehardiman Senior Member

    Possible, but maybe not realistic. Like a modern MLB, they would need to be buttoned up tight or the down flooding would get to them first.
     
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  3. fallguy
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    fallguy Senior Member

    I don't know enough to comment, but my first thought was impractical..open doors, open wells, things go wrong fast
     
  4. comfisherman
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    comfisherman Senior Member

    I'd be doubtful they would right. I'm not familiar with the Norwegian versions but spent a lot of time on the Alaska versions that start around 2:1 length to beam ratio. Not much takes these things down aside from running aground. I've seen the 58s operate in some insane weather operated by the toughest men I've ever met military included. I'd Hazzard nobody has the guts to operate these in weather rough enough to need self righting.
     
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  5. Will Gilmore
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    Will Gilmore Senior Member

    My first thought is, if they were not self righting, they wouldn't stay upright in the first place.

    There's a lot of displacement deep below the waterline and tall superstructure. Length isn't really a factor except thay are so short, if they didn't acts like Weebles on the water, they would be easy to ends over end in a sea.
     
  6. James Wellington
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    James Wellington Junior Member

    Yes, if completely tight, and heavier on the bottom, shoyld self right as the MLBs do.
     
  7. James Wellington
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    James Wellington Junior Member

    Everything watertight.
     
  8. James Wellington
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    James Wellington Junior Member


    Yet like the alaska boats, these are all over the artic. And if airtight.
     
  9. James Wellington
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    James Wellington Junior Member

    I like those Fred Wahl 'famous 58s' too. But they are all steel. The norwegians make them in aluminum , which i prefer. And various lengths.
     
  10. comfisherman
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    comfisherman Senior Member

    Steel with aluminum superstructure is common for both the Norwegian rule beaters and the Alaskan 58s. Wahl does all steel but they are the Wal-Mart of the super 8 game. Hansen, delta, and whatever van peer is called now do iterations of steel with another type of superstructure. Delta has even done a glass house steel hull, as well as the all glass far boy.

    They are all watertight on deck but the week point is windows, old rozema found that out with an errant fire extinguisher demoing the bar pilot self righting.


    I've seen the 58s that are slightly smaller operate well into storm warnings some with gear and icing. I'd not be shocked if icing takes one out eventually but to date they've all died of rocks. Kodiak isle, Cap'n Andrew, original icy mist... etc al died of jagged rocks and a big Swell.

    I've operated around Stella when I was rolling on a much bigger vessel and they were doing better than us rocking and rolling. She lifts out of the water like a travel lift pulling a basket ball. Any wave with the force capable of pushing one over (I shudder to think of the wind, DO pushed the star' in sustained storm force winds so it's a rare wind that beats it) will certainly blow windows out. After the windows are gone it'd game over for any of these if they were turned turtle.
     
  11. jehardiman
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    jehardiman Senior Member

    Yep.
     
  12. bajansailor
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    bajansailor Marine Surveyor

    Assuming that no windows get blown out, and no doors or vents are open, if a large wave did catch one of these broadside with enough energy to capsize it, bear in mind that the extreme beam will then make it VERY stable when inverted.
    The wheelhouse then needs to be relatively higher, to provide more buoyancy deeper down when inverted, to try to right her, never mind that when right ways up she might then look a bit 'top heavy' (like so many self righting lifeboats do).
     
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  13. James Wellington
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    James Wellington Junior Member

    Thanks to all respondants so far for the extra info. Its now seems like these boats can be quite good , AS LONG AS one can keep off of rocks. And can be self righting too, as long as the windows hold. In my reasearch, it seems like one can get windows as strong as you like, like ballistic glass n armoured cars, etc. I saw one company that was dropping 10kg steel balls on them from 30' height.....THREE times! That was their test. I think a german or dutch company. So if I understood you, they look high, topheavy, but that pilothouse/ cabin is an watertight compartment , trying to float up if that 100 foot rogue wave capsizes you! Re iceing, one Finnish company, Kewatec, even makes heated decks, etc to account for that.
     
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  14. comfisherman
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    comfisherman Senior Member

    I dunno, no buying self righting. I'd actually go a step forward and say they would be barge like once over. I've seen on that's a precursor to the walls tip from a slack tank, they had a heck of a time righting it with a pretty big crane and salvage bags. It was only 19 or 20 wide on a 58 waterline. Can't imagine rolling those barges over picture above.
     
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  15. jehardiman
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    jehardiman Senior Member

    Yeah, but here is where the betwixt and between comes.... If the sea is running high enough that 1 wave set can flip it over, then it is likely that another wave set has enough energy to right it again.... Not that the vessel will necessarily survive either wave set. Everyone generally agrees that if it is knocked over, down flooding will occur. Survival at that point is just luck.
     
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