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Re: Slipping into acceptance

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  • nutty_boats
    ... I didn t say Never get wet , rather that getting wet should not be part of the expectation. I have been out in wind and waves on bays (not open ocean) in
    Message 1 of 49 , May 1, 2010
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      Chris:

      --- In boatdesign@yahoogroups.com, Chris Ostlind <lunadadesign@...> wrote:
      >
      > Again, comments within the body of the post...
      >
      >
      >
      > On Fri, Apr 30, 2010 at 9:01 AM, nutty_boats <nutty_boats@...> wrote:
      >
      > >
      > > I am talking about a boat about the size of Slider, or Slipper, used for
      > > recreational sailing, day sailing, and it seems as if your solution, here
      > > quoted:
      > >
      > > > It's my opinion that sailors in the boats of the size mentioned better
      > > get
      > > > used to the reality that they are likely to get wet.
      > >
      > > is not an acceptable answer. When one is on a boat out in the water, there
      > > is always the possibility of getting wet, but for a short, pleasure cruise,
      > > one should not have the expectation of getting wet, especially not here
      > > where the water is always cold.
      > >
      > > For racing, yes, I agree with you 100%. For racing, I'd do everything you
      > > mention, including the expectation of getting wet.
      > >
      >
      >
      >
      > T, after many, many years of rec and race sailing on boats in the "around
      > 16' size"... If you are not prepared to get wet, whatever it is that you are
      > doing out there, you have chosen the wrong sport. One look at the
      > surroundings will give you the clue. Suggesting that "is not acceptable" as
      > a deal breaker is akin to telling an offroad motorcyclist that he should
      > never expect to get dirty, or that a recreational cuisine chef will not
      > find cooking splatter on their stove top. If the water is cold, you wear
      > stuff to account for the fact, you don't suggest to a designer that the only
      > solution is to make sure that the occupants never get wet.
      >
      I didn't say "Never get wet", rather that getting wet should not be part of the expectation. I have been out in wind and waves on bays (not open ocean) in boats 16' and under without getting wet and I expect that neither Slider nor Slipper would get me wet in the same conditions.
      >
      >
      >
      > > Slipper, because of its simplicity, is about as clean topsides as is
      > > practical. That's why I look again at the underwater shape as the answer to
      > > Ray's question on how we can improve Slipper's performance, simply and
      > > easily?
      > >
      >
      >
      >
      > I'm not here to dog Ray's slider, or Slipper, because I think they are valid
      > expressions and it's clear that Ray is having a blast in spite of the
      > currently expressed angst. But... there's a lot that could be done to both
      > boats to minimize above waterline drag signatures and it has everything to
      > do with topsides issues. Only Ray can decide if this effort is worthwhile
      > when measured against his philosophical approach to the design of these
      > boats.
      >
      Yes!
      >
      >
      >
      > > The answer that comes to mind applies to both multi-hulls and light
      > > mono-hulls, namely to give more lateral resistance. There are a few ways of
      > > doing that, and the way the boat is to be used and the conditions in which
      > > it is to be sailed dictate which of those ideas are best for each use.
      > >
      > >
      >
      >
      > Increasing lateral resistance, as you have suggested, will certainly
      > increase the underwater drag profile and be a source of even more complexity
      > when one looks at the design briefs as supplied by Ray for both efforts. We
      > are talking about reducing drag signatures for a boat and specifically
      > looking at above waterline conceptual approaches to that end. It would seem
      > reasonable to hold off on the suggestions that full keel surfaces on light,
      > quick multihulls, would probably be best held in retention for another day?
      >
      > Drag is drag, T. You don't solve above waterline drag concerns by adding
      > additional, underwater drag, well outside the required behavior model of the
      > design brief in order to solve the first. I'll accept that you know little
      > about multihull design issues and that this suggestion comes from a
      > preferred design mode, as you wish to apply said mode to sailing craft. In
      > this case, however, it just isn't going to work as advertised.

      Absolute minimum drag is not a holy grail to be grasped. There are times when a little extra drag in one area can yield large benefits in another. Boat design is compromise. Balancing the plusses and minuses to each design consideration makes for a successful design.

      I think Ray hit a home run with his Slider design, balancing the various issues into a design that matches his specifications. I wouldn't build one myself, only because I have a different set of specifications that I am designing for, but I can appreciate a good design when I see it, and I agree that Slider is a good design. Good work, Ray!

      Now he is trying Slipper, as a cartopable variation of Slider. While Slipper is close to the same length as Slider, it is much lighter, which, among other things, leads me to suspect that it does not have sufficient lateral resistance. In my work with light weight monohulls, insufficient lateral resistance can lead to all sorts of problems when the wind pipes up, up to losing control of the boat in the worst case scenarios, while in lesser conditions the greater effort to maintain control greatly outstrip a slight increase of drag brought on by the addition of a keel to increase lateral resistance. To me, the problems of Slipper sound like the same ones found in keelless lightweight monohulls.

      I would NOT recommend putting a full-length keel on Slipper, for reasons I have already mentioned. One that is no more than about half length might work, like the one found on the racing yacht Stormvogel, might be the answer.

      Yes, I know that adding lateral resistance will add to (shudder!) drag, but the benefits may be worth it.

      T. Lee.
      >
      > Chris Ostlind
      > Lunada Design
      > www.lunadadesign.com
      >
      >
    • nutty_boats
      ... I didn t say Never get wet , rather that getting wet should not be part of the expectation. I have been out in wind and waves on bays (not open ocean) in
      Message 49 of 49 , May 1, 2010
      • 0 Attachment
        Chris:

        --- In boatdesign@yahoogroups.com, Chris Ostlind <lunadadesign@...> wrote:
        >
        > Again, comments within the body of the post...
        >
        >
        >
        > On Fri, Apr 30, 2010 at 9:01 AM, nutty_boats <nutty_boats@...> wrote:
        >
        > >
        > > I am talking about a boat about the size of Slider, or Slipper, used for
        > > recreational sailing, day sailing, and it seems as if your solution, here
        > > quoted:
        > >
        > > > It's my opinion that sailors in the boats of the size mentioned better
        > > get
        > > > used to the reality that they are likely to get wet.
        > >
        > > is not an acceptable answer. When one is on a boat out in the water, there
        > > is always the possibility of getting wet, but for a short, pleasure cruise,
        > > one should not have the expectation of getting wet, especially not here
        > > where the water is always cold.
        > >
        > > For racing, yes, I agree with you 100%. For racing, I'd do everything you
        > > mention, including the expectation of getting wet.
        > >
        >
        >
        >
        > T, after many, many years of rec and race sailing on boats in the "around
        > 16' size"... If you are not prepared to get wet, whatever it is that you are
        > doing out there, you have chosen the wrong sport. One look at the
        > surroundings will give you the clue. Suggesting that "is not acceptable" as
        > a deal breaker is akin to telling an offroad motorcyclist that he should
        > never expect to get dirty, or that a recreational cuisine chef will not
        > find cooking splatter on their stove top. If the water is cold, you wear
        > stuff to account for the fact, you don't suggest to a designer that the only
        > solution is to make sure that the occupants never get wet.
        >
        I didn't say "Never get wet", rather that getting wet should not be part of the expectation. I have been out in wind and waves on bays (not open ocean) in boats 16' and under without getting wet and I expect that neither Slider nor Slipper would get me wet in the same conditions.
        >
        >
        >
        > > Slipper, because of its simplicity, is about as clean topsides as is
        > > practical. That's why I look again at the underwater shape as the answer to
        > > Ray's question on how we can improve Slipper's performance, simply and
        > > easily?
        > >
        >
        >
        >
        > I'm not here to dog Ray's slider, or Slipper, because I think they are valid
        > expressions and it's clear that Ray is having a blast in spite of the
        > currently expressed angst. But... there's a lot that could be done to both
        > boats to minimize above waterline drag signatures and it has everything to
        > do with topsides issues. Only Ray can decide if this effort is worthwhile
        > when measured against his philosophical approach to the design of these
        > boats.
        >
        Yes!
        >
        >
        >
        > > The answer that comes to mind applies to both multi-hulls and light
        > > mono-hulls, namely to give more lateral resistance. There are a few ways of
        > > doing that, and the way the boat is to be used and the conditions in which
        > > it is to be sailed dictate which of those ideas are best for each use.
        > >
        > >
        >
        >
        > Increasing lateral resistance, as you have suggested, will certainly
        > increase the underwater drag profile and be a source of even more complexity
        > when one looks at the design briefs as supplied by Ray for both efforts. We
        > are talking about reducing drag signatures for a boat and specifically
        > looking at above waterline conceptual approaches to that end. It would seem
        > reasonable to hold off on the suggestions that full keel surfaces on light,
        > quick multihulls, would probably be best held in retention for another day?
        >
        > Drag is drag, T. You don't solve above waterline drag concerns by adding
        > additional, underwater drag, well outside the required behavior model of the
        > design brief in order to solve the first. I'll accept that you know little
        > about multihull design issues and that this suggestion comes from a
        > preferred design mode, as you wish to apply said mode to sailing craft. In
        > this case, however, it just isn't going to work as advertised.

        Absolute minimum drag is not a holy grail to be grasped. There are times when a little extra drag in one area can yield large benefits in another. Boat design is compromise. Balancing the plusses and minuses to each design consideration makes for a successful design.

        I think Ray hit a home run with his Slider design, balancing the various issues into a design that matches his specifications. I wouldn't build one myself, only because I have a different set of specifications that I am designing for, but I can appreciate a good design when I see it, and I agree that Slider is a good design. Good work, Ray!

        Now he is trying Slipper, as a cartopable variation of Slider. While Slipper is close to the same length as Slider, it is much lighter, which, among other things, leads me to suspect that it does not have sufficient lateral resistance. In my work with light weight monohulls, insufficient lateral resistance can lead to all sorts of problems when the wind pipes up, up to losing control of the boat in the worst case scenarios, while in lesser conditions the greater effort to maintain control greatly outstrip a slight increase of drag brought on by the addition of a keel to increase lateral resistance. To me, the problems of Slipper sound like the same ones found in keelless lightweight monohulls.

        I would NOT recommend putting a full-length keel on Slipper, for reasons I have already mentioned. One that is no more than about half length might work, like the one found on the racing yacht Stormvogel, might be the answer.

        Yes, I know that adding lateral resistance will add to (shudder!) drag, but the benefits may be worth it.

        T. Lee.
        >
        > Chris Ostlind
        > Lunada Design
        > www.lunadadesign.com
        >
        >
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