Swain BS_36 Stability curve

Discussion in 'Stability' started by junk2lee, Mar 9, 2011.

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  1. Jack Hickson
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    Jack Hickson New Member

    You ill be shocked when you find out how much easier it is, and how much better the result.
    Buehlers problem was caused by excessive flare in the topsides, something I have heard he is rectifying. When you take the buoyancy of the part left out by the flare, times it's distance from the centerline, and convert it to foot pounds of righting moment , you have a huge reduction in righting moment. .
    Some do it for a narrow waterline, but only when the boat is level, which it rarely is, given its tenderness. Some do it for aesthetics, but most round bilged boats have very little flare between the deck and waterline.
     
  2. Jack Hickson
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    Jack Hickson New Member

    This curve is getting very close to 175 degrees AVS , without considering many additional positive factors. It is far better than many of the "Modern " commercially mass produced designs which many consider adequate for offshore yachts.
     
  3. Ad Hoc
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    Ad Hoc Naval Architect

    Please provide ABS approval letter stating it meets their rules. If you cannot, then you claim is just that..a baseless claim with no supporting evidence....
     
  4. MikeJohns
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    MikeJohns Senior Member

    I'd suggest it proves the opposite. The damage proves the impact.

    Would you try and use an argument that ran like this:
    My car was hit repeatedly by a truck with no damage so therefore...........
    We all have enough experience of highway smashes to know why that sort of argument would be baloney.

    That's what these tales amount to.

    Like the boat which supposedly T boned a barge:rolleyes: It was either BS or it rode up. Despite Brent's protestations it turned out when a reliable witness came forward that it did simply ride up on its stem since the barge was almost awash at the time. The nature of the impact is indicated by the resulting damage, unfortunately there's no magic but there is a lot of distortion in the marketing.

    Many boats have been washed over a reef or left high and dry and been recovered. If there was minimal damage it's simply because it experienced minimal impact. The terror of finding yourself bumping over a reef makes up the rest of the tale and then it grows in the telling.
    Abalone divers here have often survived with their boats, being washed over very nasty reefs and even the poorly built 'SharkCats' of the day would survive at times albeit with a few scratches and dents and broken outboard skegs and props.

    A twin hull or twin keel boat being deposited upright on a reef and carried on by the next wave can get across a reef with surprisingly little damage with a little luck, but a boat falling even half a meter onto its plating on a reef would suffer some serious and very obvious damage.

    So its back to the logic of the truck hit my car argument .

    A truck hit my car and there was no damage, therefore my car is incredibly strong !!!
     
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  5. TeddyDiver
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    TeddyDiver Gollywobbler

    I wouldn't worry about the tenderness in small angles of heel too much either. I'm worried about the refusal (or not even giving some help for the others willing to do that) of further investigations of seaworthiness and some structural issues. Just makes me think Brent is hiding something he knows terribly well and tries to cover it up with "smoke" aka jumping into irrelevant conclusions and hear says...
     
  6. Tad
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    Tad Boat Designer

    :rolleyes: Well that was predictable.........Please cite anywhere in this or any other thread were I call anyone anything?
     
  7. Tad
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    Tad Boat Designer

    I claim nothing of the sort.......I have no idea if your boat will pass any ABS rules......The title of this thread is Swain BS 36 Stability curve..........The ABS "Guide for building and Classing Offshore Racing Yachts" is a structural guide, it does not even mention stability, is many years out of date, and was intended for racing yachts.........Therefore I would suggest it is indeed irrelevant to this thread.........
     
  8. Tad
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    Tad Boat Designer

    See post #105 in this thread, AVS stands at 131 degrees, I wouldn't call that particularly close to 175......but others might.......

    "many additional positive factors".......Like what?

    The sealed mast? Do any BS 36's actually have a sealed mast? It's not indicated on the plans...... And if so could you please show, to use your ABS rules wording, "a systematic analysis based on sound engineering principals" how your tube and the associated welds will remain intact when inverted..........
     
  9. Jack Hickson
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    Jack Hickson New Member

    Check attachment 55653 ,posted by Tad. It shows AVS much closer to 175 degrees.
    Tads suggestion for a stability test ,was an in the water stability test, which proves nothing ,in terms of ultimate stability.
    All steel masts on BS 36's are sealed. It's the only way you can keep corrosion out, as the book points out.
    Additional factors are fuel and water in the bilge tanks, personal effects and interior, mostly well below the waterline. etc etc.
     
  10. Jack Hickson
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    Jack Hickson New Member

    Check post 248 , again, as many times as it takes .
     
  11. Jack Hickson
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    Jack Hickson New Member

    If a truck t-boned your car at 6 knots, without damaging it, it would prove it incredibly strong.
    The freeboard of the barge was about three feet.
    The boats which pounded across the reefs and lee shores were all single keelers.One pounded for weeks .
    Tad , go talk to Don, not far from you, and to his crew. Dive down and count the number of keels. Only one, last time I looked. You may notice a slight, barely noticeable dent in the half inch plate on the bottom, the only damage in that incident.
    Look at his photos and read his book, then tell him he and his crew are all liars.
    You know far more about what happened than all the people who were actually there?
     
  12. Tad
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    Tad Boat Designer

    What "in the water stability test".....no......I did not suggest anything of the sort.....I offered to do an inclining experiment...this is to establish actual VCG vs calculated VCG.
     
  13. Tad
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    Tad Boat Designer

    All those (and many more, around 160 items in all) are included in my weight study published in this thread weeks ago......revise it all you like....correct me were I'm wrong......but an inclining and freeboard measurements will be easier and far more exact........I only need a completed boat (built as designed) in Silva Bay for a few hours.........
     
  14. Wynand N
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    Wynand N Retired Steelboatbuilder

    Brent Swain, Jack Hickson or whatever you want to call yourself.
    Please stop making a fool of yourself. For many years you had pestered us with your sly and dishonest ways of misquoting, distorting replies to suit your ideas you want to impose on others.

    Brent Swain, you had your bacon grilled all over the internet, banned because of this very nature of you and then you sneak back into the door here after the transverse frames and origami topics with a new pseudonym as Jack Hickson. You started off in a civil manner - even accepted advice at a point - but as I said before, your past dictates your future and here we have you back with your bully tactics and soon it will be insults and name calling we will have to endear from you.

    Tad did some stability -which you incidentally failed to deliver the last many years or not have the ability to produce one - and the figures are I would say withing 2-3% accurate for the boat and far off the fabled 170 degrees we are made to believe by you the last few years, and still you are gunning it. Get real man, please do not insult the intelligence of people visiting this thread, less so professionals that are your peers in boat design and construction.
    You are destroying any goodwill if any left chasing down others and into doing so, revealing your true colors and short comings of your design....

    This thread should only been done and dusted quite a few pages back, and you keep at it trying to get people to respond to keep this going for your own benefit to step on the boating establishment. This thread is fast becoming another origami post fiasco if not stopped soon. Perhaps one should get the moderator involved into this...

    A silly claim was made in the first post, it was subsequently proven wrong with calculations etc by well respected and reputable qualified naval architects and engineers. That took care of this thread and unless some mayor design alterations are made to get some really worthwhile changes into the stability curve to challenge the 175 degree claim, this thread/topic has reached its sell by date.

    Lastly; gentleman, we had all heard this before, but I will repeat it again and perhaps we should take heed to that.

    Do not argue with a fool....he will drag you down to his level and will beat you with experience everytime and someone passing by would not know the difference between you.

     

  15. Tad
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    Tad Boat Designer


    Couldn't agree more Wynand........My participation in this thread has always been to try and correct misinformation concerning the stability (and the calculation thereof) of small steel cruising boats......that would be the only reason I may continue to post here........
     
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