The old man and the sea: 73 year-old circumnavigation

Discussion in 'Sailboats' started by JosephT, Dec 6, 2012.

  1. JosephT
    Joined: Jun 2009
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    JosephT Senior Member

    My eyes about popped out when I read this. Just look at that boat...a real wave surfer. Seems it would be hard to steer though. Would like to learn more about that hull shape.

    http://edition.cnn.com/2012/11/28/sport/sven-yrvind-sail-around-world-smallest-boat/index.html

    RKJ states "In a boat that size he's going to be rolled around like he's inside a giant washing machine. Sir Robin Knox-Johnston"

    I wholly concur, but what can you tell a guy like this? Can't teach an old dog new tricks?

    [​IMG]
     
  2. Manie B
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    Manie B Senior Member

  3. JosephT
    Joined: Jun 2009
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    JosephT Senior Member

    Thanks for the additional info Manie. He truly does look like the type of character who is just doing this for novelty. I don't believe he cares if it takes twice as long, or if he gets sick twice as much. He's in it for himself & the whole experience. Well, he's set his mind to it. All we can do is just sit back & laugh at his GPS tracker route (if he's using GPS/Spot or equivalent).

    It will be fun to watch that's for sure. It's not every day you get to see a boat like that venture off.
     
  4. messabout
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    messabout Senior Member

    Huge cajones and small brain. He does have credentials. The boat should be christened Sabot.
     
  5. sharpii2
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    sharpii2 Senior Member

    He's been in the southern high latitudes before in boats 20ft and under.

    Admittedly, this new boat of his looks like a tub. With a planned displacement of over a ton and a half on a 10ft minus WL, giving it a D/L of at least 1370, it certainly is.

    He expects to get an average of only 2kts. I suspect he will get closer to three.

    The boat has no keel, but has a huge Center Board in the bow and twin rudders on the transom. All are retractable. Whether it will roll like a barrel in the surf, time will tell.

    He has what amounts to two roller furling standing Lug rigs, which he intends to step side by side, close to the bow of the boat.

    In big wind and consistent waves, I expect it to track quite well, as it will have, with the CB retracted, the ultimate lee helm, with little chance of broaching.

    In big winds and confused seas (if they actually ever occur there) he may just dismount the rigs, retract the CB and rudders, shut himself below, and just ride it out. He could retract the rudders (their blades rotate up 180 deg.)
    and just 'hang on' the CB, sliding aft from the waves.

    Having no plane like surfaces below and having well rounded bilges, leaving nothing to 'trip' it, I expect it may well prove more seaworthy in that region than boats three times its size.

    Like other boats of his design, this seems quite under canvassed for its displacement, but he has crossed oceans before with seemingly under sized rigs. As far as I know, his Briss IV, S/D of about 8.5 was the most under canvased boat to cross the Atlantic. I believe Felicity Anne came in a close 2nd, with an S/D of around 10.

    I have been following this man's adventures since the mid '70's. He designs by 'blow of the eye' and he learns from past experiences.

    He is no joke.
     
  6. kvsgkvng
    Joined: Jan 2012
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    kvsgkvng Senior Member

    Pardon my ignorance, but in my mind if this "egg-like" boat would have sufficient ballast, it would make it stiff enough (meaning moving only up and down) with lateral resistance of protruding foils. I am not mentioning longitudinal stability here.
    My philosophy is that the ballast would keep it vertical and the foils would prevent from sudden rolling by providing lateral resistance. The loaded shell then would just move mostly vertically rather than rolling side to side.
    If this boat would not have heavy ballast, then I would envision it rolling like a lot. I think that the longitudinal stability of this shell would be as any other boat of this length. Otherwise I think it is early to tell.
    Could someone please explain if my observation is wrong?
    Thanks.
     
  7. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    It may not need as much ballast as you may think.

    If heavier stores, such as drinking water and canned food are kept low in the boat and restrained, they act as ballast. A good way to illustrate this point is to get a tub of margarine, take half of the margarine out from the top, put the lid back on, then float the tub. You will find it will be very difficult to get it to capsize and it may even stubbornly refused to float upside down.

    The real purpose of fixed ballast is to lower the Center of Gravity in relation to the Center of Buoyancy. On a fin keel yacht, the ballast has to not only lower the CG of the boat but must also overcome the buoyancy of the keel itself. Hence, when we usually think of ballast, we think of very dense material. But if it is stored in the hull itself and there is no large buoyant fin under it, just about anything will do, even if it is less dense than water.

    Keels and other leeway preventing surfaces may dampen rolling, but only if they are large in area and/or well distributed along the length of the under body. Otherwise, they may actually induce it. But even if they fit these two conditions, they all can 'trip' a boat, if the boat is hit by a breaking wave.

    To help illustrate my first point, I have attached a sketch of one of my designs. As you can see, its twin fin keels aren't very deep and they are about a third of the waterline in length. They have a considerable amount of area as well. They are ballasted with re-bar and concrete.

    The main point of this sketch is to show the high cabin sole and the large amount of fresh water stored under it.

    What Mr. Yrvin is building amounts to a miniature ark, though not a great sailboat, may be the ultimate lifeboat.
     

    Attached Files:

  8. JosephT
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    JosephT Senior Member

    sharpii2, thanks for the additional info. After reading about the sail, centerboard & rudder config normal cruising shouldn't be too bad (hopefully) if he can get that centerboard & set of rudders to hold him on course.

    You have to admire the spirit of Yrvind. Hopefully that hull won't drive him mad. We'll see if the story doesn't change to "The old crazy man and the sea".
     

  9. alan white
    Joined: Mar 2007
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    Location: maine

    alan white Senior Member

    Beats a nursing home. Good for him. A hammock might allieve some of that sea sickness potential.
     
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