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Re: [bolger] Safety of ballasted vs. unbalasted open boats

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  • Michael Surface
    Hi All Self righting is possible in a non-ballasted boat. Bolger s Birdwatcher design is a good example. With the Birdwatcher high freeboard and low
    Message 1 of 7 , Aug 1, 2000
      Hi All

      Self righting is possible in a non-ballasted boat. Bolger's Birdwatcher
      design is a good example. With the Birdwatcher high freeboard and low
      passenger weight is used to make the boat self righting from a nearly 90
      degree knockdown. Jim Michalak has several designs that use the birdwatcher
      approach to provide self-righting with little or no ballast.

      Michael Surface Still building


      >From: KF4call@...
      >Reply-To: bolger@egroups.com
      >To: bolger@egroups.com
      >Subject: Re: [bolger] Safety of ballasted vs. unballasted open boats
      >Date: Tue, 1 Aug 2000 19:07:16 EDT
      >
      >To all,
      > There is another safety related design characteristic that is not yet
      >been mentioned here...it is the "self righting" capacity of the boat. When
      >I
      >was faced with the choice, I went with a weighted keel design. This was
      >because the boat was also described as "self righting". (Bolger designed
      >Oldshoe) Is it possible to get "self righting" capability that will work
      >in
      >most conditions in an unballasted boat? Here in Florida , USA, we must be
      >prepared for sudden afternoon thunderstorms with winds that have
      >substantial
      >strength and unpredictable direction , but (in my sailing area) not
      >especially large seas.
      >Regards, Warren

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    • Chris Crandall
      ... I guess this is the right place to mention my concerns about this. Using passenger weight to make a boat self-righting, like Birdwatcher, doesn t seem to
      Message 2 of 7 , Aug 2, 2000
        On Wed, 2 Aug 2000, Michael Surface wrote:
        > Self righting is possible in a non-ballasted boat. Bolger's
        > Birdwatcher design is a good example. With the Birdwatcher high
        > freeboard and low passenger weight is used to make the boat self
        > righting from a nearly 90 degree knockdown. Jim Michalak has several
        > designs that use the birdwatcher approach to provide self-righting
        > with little or no ballast.

        I guess this is the right place to mention my concerns about this.

        Using passenger weight to make a boat self-righting, like Birdwatcher,
        doesn't seem to make sense to me.

        In a 90 degree knockdown, the passengers shift from the bottom to the hull
        sides--they don't velcro their butts to what is now a vertical surface.
        Their weight shifts to *hold the boat down*, not help it right.

        I have always wondered what in he** Bolger meant by this.
      • Richard Spelling
        I ve had the same thoughts. I imagine you have the crew lean up against the floor to right the boat. Richard Spelling, http://www.spellingbusiness.com/boats
        Message 3 of 7 , Aug 2, 2000
          I've had the same thoughts. I imagine you have the crew lean up against the
          floor to right the boat.

          Richard Spelling, http://www.spellingbusiness.com/boats
          From the muddy waters of Oklahoma

          ----- Original Message -----
          From: "Chris Crandall" <crandall@...>
          To: <bolger@egroups.com>
          Sent: Wednesday, August 02, 2000 10:49 AM
          Subject: Re: [bolger] Safety of ballasted vs. unbalasted open boats


          > On Wed, 2 Aug 2000, Michael Surface wrote:
          > > Self righting is possible in a non-ballasted boat. Bolger's
          > > Birdwatcher design is a good example. With the Birdwatcher high
          > > freeboard and low passenger weight is used to make the boat self
          > > righting from a nearly 90 degree knockdown. Jim Michalak has several
          > > designs that use the birdwatcher approach to provide self-righting
          > > with little or no ballast.
          >
          > I guess this is the right place to mention my concerns about this.
          >
          > Using passenger weight to make a boat self-righting, like Birdwatcher,
          > doesn't seem to make sense to me.
          >
          > In a 90 degree knockdown, the passengers shift from the bottom to the hull
          > sides--they don't velcro their butts to what is now a vertical surface.
          > Their weight shifts to *hold the boat down*, not help it right.
          >
          > I have always wondered what in he** Bolger meant by this.
          >
          >
          >
          >
          > Bolger rules!!!
          > - no cursing
          > - stay on topic
          > - use punctuation
          > - add your comments at the TOP and SIGN your posts
          > - add some content: send "thanks!" and "ditto!" posts off-list.
          >
        • GHC
          At 90 degrees (sail in the water), the crew usually sits on the centerboard... GHC
          Message 4 of 7 , Aug 2, 2000
            At 90 degrees (sail in the water), the crew usually sits on the centerboard...

            GHC

            At 10:52 AM 8/2/2000 -0500, you wrote:
            >I've had the same thoughts. I imagine you have the crew lean up against the
            >floor to right the boat.
            >
            >Richard Spelling, http://www.spellingbusiness.com/boats
            >From the muddy waters of Oklahoma
            >
            >----- Original Message -----
            >From: "Chris Crandall" <crandall@...>
            >To: <bolger@egroups.com>
            >Sent: Wednesday, August 02, 2000 10:49 AM
            >Subject: Re: [bolger] Safety of ballasted vs. unbalasted open boats
            >
            >
            >> On Wed, 2 Aug 2000, Michael Surface wrote:
            >> > Self righting is possible in a non-ballasted boat. Bolger's
            >> > Birdwatcher design is a good example. With the Birdwatcher high
            >> > freeboard and low passenger weight is used to make the boat self
            >> > righting from a nearly 90 degree knockdown. Jim Michalak has several
            >> > designs that use the birdwatcher approach to provide self-righting
            >> > with little or no ballast.
            >>
            >> I guess this is the right place to mention my concerns about this.
            >>
            >> Using passenger weight to make a boat self-righting, like Birdwatcher,
            >> doesn't seem to make sense to me.
            >>
            >> In a 90 degree knockdown, the passengers shift from the bottom to the hull
            >> sides--they don't velcro their butts to what is now a vertical surface.
            >> Their weight shifts to *hold the boat down*, not help it right.
            >>
            >> I have always wondered what in he** Bolger meant by this.
            >>
            >>
            >>
            >>
            >> Bolger rules!!!
            >> - no cursing
            >> - stay on topic
            >> - use punctuation
            >> - add your comments at the TOP and SIGN your posts
            >> - add some content: send "thanks!" and "ditto!" posts off-list.
            >>
            >
            >
            >
            >
            >Bolger rules!!!
            >- no cursing
            >- stay on topic
            >- use punctuation
            >- add your comments at the TOP and SIGN your posts
            >- add some content: send "thanks!" and "ditto!" posts off-list.
            >
            >
          • T Webber
            My son, a friend and I did some capsize testing on Michalak s Scram Pram. Yes, In a capsize, the crew tends to aggregrate on the side of the hull. It is
            Message 5 of 7 , Aug 2, 2000
              My son, a friend and I did some capsize testing on Michalak's Scram Pram.
              Yes, In a capsize, the crew tends to aggregrate on the side of the hull. It
              is possible to move back towords the bottom. This does shift the c/g of the
              capsized hull. In the Scram Pram and I assume the B/W, the windowed portion
              of the topsides does provide a lot of flotation. With the Scram Pram, any
              water ballast was enuff to right the boat when this movement occurred. In
              an actual capsize, my wife (chivalry is not dead, but I'm doing my part!!!)
              was able to right the hull with only 10 lbs of pressure on the lee board -
              no ballast in the tanks at all.

              On Birdwatcher, Scram Pram, IMB, Jewel Box and similar, it helps to turn
              the plans sideways and "guestimate" where the center of bouyancy(sp) is and
              judge for yourself what additional righting moment is created by crew
              movement. Sometimes in a 90 degree capsize, the crew must be settled down a
              bit before they will move!

              Tim - the one near Houston

              At 10:49 AM 08/02/2000 -0500, you wrote:
              >On Wed, 2 Aug 2000, Michael Surface wrote:
              >> Self righting is possible in a non-ballasted boat. Bolger's
              >> Birdwatcher design is a good example. With the Birdwatcher high
              >> freeboard and low passenger weight is used to make the boat self
              >> righting from a nearly 90 degree knockdown. Jim Michalak has several
              >> designs that use the birdwatcher approach to provide self-righting
              >> with little or no ballast.
              >
              >I guess this is the right place to mention my concerns about this.
              >
              >Using passenger weight to make a boat self-righting, like Birdwatcher,
              >doesn't seem to make sense to me.
              >
              >In a 90 degree knockdown, the passengers shift from the bottom to the hull
              >sides--they don't velcro their butts to what is now a vertical surface.
              >Their weight shifts to *hold the boat down*, not help it right.
              >
            • Chris Crandall
              ... Yes. Alas, when one goes outside and hauls on the centerboard, it s hardly to be considered self-righting.
              Message 6 of 7 , Aug 2, 2000
                On Wed, 2 Aug 2000, GHC wrote:
                > At 90 degrees (sail in the water), the crew usually sits on the
                > centerboard...

                Yes. Alas, when one goes outside and hauls on the centerboard, it's
                hardly to be considered self-righting.
              • KF4call@aol.com
                Chris, ... For a long time I thought that maybe the answer was obvious... and I was the only one who didn t get it , the one who didn t understand how the
                Message 7 of 7 , Aug 2, 2000
                  Chris,

                  I'm glad that you mentioned this:

                  >Using passenger weight to make a boat self-righting, like Birdwatcher,
                  >doesn't seem to make sense to me.

                  >In a 90 degree knockdown, the passengers shift from the bottom to the hull
                  >sides--they don't velcro their butts to what is now a vertical surface.
                  >Their weight shifts to *hold the boat down*, not help it right.>

                  For a long time I thought that maybe the answer was obvious... and I was
                  the only one who didn't "get it", the one who didn't understand how the
                  weight of the crew would be distributed to contribute to self righting.

                  There is a big difference between the theory and what can be counted on
                  when you are cold, wet, tired and in a bad chop as it is getting on toward
                  dusk. But I would like to hear from the folks in Chebaccos (or other
                  non-ballasted boats) who have been surprised by bigger than expected gusts
                  of wind.

                  Regards, Warren
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