Why I'm Following Sven Yrvind

Discussion in 'Sailboats' started by sharpii2, May 7, 2020.

?

Do you believe Sven's latest Ex Lex will make it to New Zeeland.

  1. Nope.

    52.9%
  2. Probably.

    23.5%
  3. Almost certainly.

    23.5%
  1. skaraborgcraft
    Joined: Dec 2020
    Posts: 32
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    Location: sweden

    skaraborgcraft Junior Member

    Im wondering if hes more likely to trip and roll in a broach with those keels he is thinking of? They might be shallow enough to stay in broken water under those circumstances.

    So he is going back to Porto Santo in May to float around in Ex Lex in the Atlantic for a few months. Why is he building another boat? He came to the realization once someone actually asked him, that going to NZ served little purpose. I will probably be quite mad if i ever get to his age. Good luck to him.

    Anyone else notice how shaky his hand was? Never saw that before he left.
     
  2. skyl4rk
    Joined: Aug 2006
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    Location: Lake Michigan

    skyl4rk Junior Member

    The thing about a narrow flat bottom boat is that it needs ballast to increase its stability. The the question becomes, is the ballast heavier than the flotation can keep above water, if the boat is flooded.
     
  3. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    Probably not.

    The actual boat is going to be made of nearly two inch thick foam core. In metric terms, if I'm doing my math right, he will get about 50 kg/sm of hull, minus of course, the wt of the foam and the wt of the skins on either side. I wouldn't be surprised if he's netting maybe 30 kg/sm of hull. The new Ex Lex may swamp, but she probably won't sink, at least not from the weight of the new, deeper, 'vertical chine-runners'.
     
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  4. Will Gilmore
    Joined: Aug 2017
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    Location: Littleton, nh

    Will Gilmore Senior Member

    Not really true. Narrow, as in length to width, shouldn't affect stability. The cross section proportions of width to height of CG are the important factors and a flat bottom, while may be more rolly, is actually the most stable. Think about a log floating in the water and a two by four. The log floats any old way, it rolls all over the place and is very unstable, but the two by four will only float on one of two 4" wide surfaces. The length has no affect.

    Now, cut the log down the middle lengthwise so you have a half round shape. It will only settle on the flat spot. Any attempt to float it on its round side will result in a slow turning over to settle back into its flat surface. Very stable.

    Ballast helps, of course.

    -Will (Dragonfly)
     
    Last edited: Mar 30, 2021
  5. skyl4rk
    Joined: Aug 2006
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    Location: Lake Michigan

    skyl4rk Junior Member

    Hmm, I didn't explain that very well. What I mean is:

    In open water with waves, the forces related to hull form will cause a flat bottom boat to keep its bottom parallel to the surface of the water, which is constantly changing. This causes rolling, following the wave surface.

    A round bottom boat is affected more by ballast, its low center of gravity has more force than the round hull form as it is affected by waves. So a ballasted round hull has less roll in waves.

    Initial stability vs. secondary stability.

    A flat bottom boat needs a relatively large amount of ballast to overcome the force of the hull form in waves, to reduce rolling.
     
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  6. Will Gilmore
    Joined: Aug 2017
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    Location: Littleton, nh

    Will Gilmore Senior Member

    That is true.
     
  7. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    This is kinda, sorta true. I think it's more true if the flat and round sections are much wider than they are deep. But if the flat main section is deeper than the round one (accomplished by narrower WL beam) the round bottom boat will snap roll more.

    The type of keel matters too. If the round bottom boat has a deep keel, perhaps with a bulb on it, it will probably snap roll more than the flat bottom will, if it has a long, shallow keel (with much more area).

    This is because the long, shallow keel produces more roll dampening than the short, deep one does.

    In the case of Yrvind's new boat, it appears that the Beam WL is going to be relatively narrow compared to the over-all Beam.

    This will produce a more gentle roll, even without a keel. The ballast, as high placed as it is, probably does little to add sail carrying ability. It does add to ultimate stability.

    As usual, he intends a very modest sail plan. Not as modest as Ex Lex 2.0, but probably less than two thirds of what we would see on a more conventional sailboat.

    Even so, he may have to get used to a whole new slant on sailing.
     
  8. JPE
    Joined: Aug 2019
    Posts: 80
    Likes: 13, Points: 8
    Location: Finland

    JPE Junior Member

    Meanwhile our controversial swede has yet again, as no surprise to anyone, changed his plans, scrapped the previous prototype, and is now building what looks to be quite a "normal" boat.

    It is also considerably shoter than the predecessor, so one may draw the conclusion that sailing to NZ has been scrapped as a goal. In his erlier post Sven says he enjoys sailing more than going anywhere specific. Again, this hardly surprises anyone. I hope he has finally found himself.
     
    Will Gilmore likes this.
  9. upchurchmr
    Joined: Feb 2011
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    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    If it is "normal" why didn't he just buy and modify one?
    Perhaps he's just fond of listening to himself - of course, who isn't?

    Is this a Finland vs Sweden thing?:D
     
    JPE likes this.
  10. skaraborgcraft
    Joined: Dec 2020
    Posts: 32
    Likes: 18, Points: 8
    Location: sweden

    skaraborgcraft Junior Member

    Sven can speak for himself, but i think it is worth bearing in mind he has a workshop full of stuff and an apartment full of books that he needs to cover rent for. If it is a goverment apartment he may only be able to stay out of the country for a maximum of 12 months, unless he finds someone to rent the apartment, something he said he had considered, but not with all his stuff in place.

    I think he enjoys workshop time as much as a few months afloat, for an 82 year old, seems like a good balance.

    I think the new boat will roll more than his last one, and recall thae last one was built because the previous to that, rolled too much! He will drive you crazy if you try to interpret his actions, best just to watch him do his thing which is ever evolving and changing. His boat building is specific to his workshop size, rather than to his actual dreams. Life is a compromise. Still fun to watch.
     
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  11. JPE
    Joined: Aug 2019
    Posts: 80
    Likes: 13, Points: 8
    Location: Finland

    JPE Junior Member

    Oh yes, we love to pick on each other

    Sven obviously is both, a builder and a sailor, and as long as he does not preach, he is fun to follow.
     
    Will Gilmore likes this.
  12. JPE
    Joined: Aug 2019
    Posts: 80
    Likes: 13, Points: 8
    Location: Finland

    JPE Junior Member

    Long time etc.

    There has been a change of plans. Sven will attempt rounding the Cape Horn against prevailing winds in his current (or future) Exlex variant.
     
  13. Will Gilmore
    Joined: Aug 2017
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    Location: Littleton, nh

    Will Gilmore Senior Member

    Wow. Ambitious for anyone. Very exciting news. I'll have to check in on his blog.
     
  14. JPE
    Joined: Aug 2019
    Posts: 80
    Likes: 13, Points: 8
    Location: Finland

    JPE Junior Member

    Oh yes. Considering the current boat concept, it would be quite a ride...
     

  15. skaraborgcraft
    Joined: Dec 2020
    Posts: 32
    Likes: 18, Points: 8
    Location: sweden

    skaraborgcraft Junior Member

    Not my cup of tea down there, and given his past experience, surprised he wants to go back at his age. Still, we all know how fast plans can change, especially with Sven. Interesting to see what he does about the rig, i would like to see how he puts together 2 rotating masts.
     
    JPE likes this.
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