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Junk Rig Glossary -updated and expanded, and an invitation

  • 02 Mar 2015 19:11
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    Reply # 3239260 on 3171528
    Anonymous member

    Hi Dave,

    Looking at the Gentry article, it appears that what's going on is exactly as written – who would've thought!

    This is one of the best parts about working on the glossary project, as far as I'm concerned – what amazing bits of information turn up! (Of course, if I've misunderstood, and somebody who really knows what they're talking about would like to point that out, that would be really interesting too :-)

    My biggest question is: does the foresail have to be a jib? Or will a schooner or ketch-rigged junk have the same kind of dynamic going on, if the sails are close enough?

    Shemaya
  • 02 Mar 2015 03:44
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    Reply # 3238615 on 3238117
    Anonymous member
    Darren Bos wrote:

    A synonym for the slot effect, by which the mainsail alters the airflow around a foresail creating a lifting windshift (more upawash) and allowing greater airflow velocity on the windward side of the foresail (Kutta condition), making the foresail more efficient than it would be on its own.

    Hi Darren,

    Just checking... are foresail and mainsail switched in this proposal, or am I missing something?

    Dave Z
  • 01 Mar 2015 19:49
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    Reply # 3238389 on 3171528
    Anonymous member

    Thanks so much – I get really lost in the long articles, but looking at this I can actually wrap my head around the various concepts. Personally it's great fun seeing the fog clear, and it's even better for the glossary progress. Thanks again to everybody!
    Shemaya
  • 01 Mar 2015 10:43
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    Reply # 3238174 on 3171528
    Deleted user

    Darren's distinction between bootstrap effect and upwash appears to be the correct one given the way the tem is used by Gentry and others.

    Last modified: 01 Mar 2015 10:43 | Deleted user
  • 01 Mar 2015 04:01
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    Reply # 3238117 on 3171528
    Deleted user

    I would suggest something like "A synonym for the slot effect, by which the mainsail alters the airflow around a foresail creating a lifting windshift (more upawash) and allowing greater airflow velocity on the windward side of the foresail (Kutta condition), making the foresail more efficient than it would be on its own."  

    In other words, not as simple as just upwash.

    Darren
  • 01 Mar 2015 01:47
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    Reply # 3238064 on 3171528
    Anonymous member

    Ah, let's hear it for running aground at opportune moments!

    As for upwash, here's what we have so far:
    Upwash:
    Divergent flow toward a foil's convex side. In a sail (vertical foil), upwash is transverse motion, flowing toward the lee. See Foil and Downwash.

    Perhaps "bootstrap effect" is one of the results of upwash? Personally, I'm also trying to get a grip on how this all relates to "slot effect," in a short definition sort of way. Slot effect also already has an entry in the glossary.

    Thoughts?

    The glossary draft can be found here, for anybody who would like to peruse and perhaps make suggestions.

    Shemaya
  • 28 Feb 2015 23:13
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    Reply # 3238010 on 3171528
    Deleted user

    I suggest that it has the same meaning as UPWASH and should be  shown as an alternative.

    The house has just run aground, it will save blowing up the dinghy.
  • 28 Feb 2015 22:51
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    Reply # 3237999 on 3171528
    Anonymous member

    Wonderful to hear all this detail! Would anybody, by chance, have enough of a grip on this concept to propose a succinct, glossary-style definition??

    Thanks so much for the references – and for the great sleepwalking story! I've woken up convinced that the boat was adrift (when it wasn't), and have felt the house rocking in the night (which it wasn't), but have not yet woken up to the adjacent house about to swing too close on its anchor (which you never know – it might :-)

    Thanks again,
    Shemaya
  • 28 Feb 2015 19:04
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    Reply # 3237892 on 3171528
    Deleted user
    I had wondered what bootstrapping meant in the sailing sense.  We use the term frequently in statistics, where it is used when you randomly resample a population to create a new distribution, when a suitable distribution for tests is not available.  Both sailing and statistics take the meaning from the more general to "pick oneself up by your own bootstraps".  http://www.phrases.org.uk/meanings/290800.html

    The Arvel Gentry description of bootstrapping is quite good for the sailing sense.
  • 28 Feb 2015 00:27
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    Reply # 3237549 on 3171528
    Deleted user

    12 minutes after i posted, Chris managed to find what i have been seeking for a long time, brilliant Chris.

    But

    Who will be awarded the credit in the dictionary Shemaya, Chris or me?
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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