GRF's rig school

<SPAN style="FONT-FAMILY: Arial; COLOR:
black; FONT-SIZE: 10pt">Essay no two... (My English teachers would be
proud apart from the spelling)<?:namespace prefix = o ns =
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<SPAN style="FONT-FAMILY: Arial; COLOR: black; FONT-SIZE:
10pt">Greame, firstly let me put the record straight.  I am not trying to
sell anything here or anywhere on the forum (apart from possibly the B14
fleet).  I have know interest in the D1 at all, I have never knowingly met
anyone from the project, and the only time I have seen one in the flesh
was at the last dinghy show, where, if I am honest I though it was quite
an ugly boat.  I am way too small (at 70kg) to ever be competitive in that
boat, and frankly I personally find single handed sailing boring - just my
opinion, but I can also understand why people enjoy it.  My only interest
is in the discussion and its accuracy (and I enjoy a good debate).  For
what it is worth I don't think you overstepped the mark. 
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<SPAN style="FONT-FAMILY: Arial; COLOR: black; FONT-SIZE:
10pt">Perhaps it is the sterility and lack of personal context inherent in
writing on forums like this, but I tend to get from a reasonable number of
your posts a rather aggressive tone.  I have no issue with you picking
fault wit designs, and I do agree with you on a number of things, its just
at that point I keep quiet, as 'me too' does not really advance the
discussion.  If you remember my initial comment on the mast bend was
that perhaps thee was a touch too much as well, but my theory was that
it was more to do with an error of the user than an error in design. 
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<SPAN style="FONT-FAMILY: Arial; COLOR: black; FONT-SIZE:
10pt">If I have jumped to a false conclusion as to your level of
knowledge on the D1 project I apologise, I had not read back through the
whole thread, and that is my mistake - sorry.  The one thing I would like
to bring up though is that you talk about it having a flexible tip when the
photos show it does not.  The first thing I did was to hold up the edge of
a bit of paper to the photo, the top third of the mast is straight, all the
bend is in the middle 25%.  This follows in the same vein as many of the
new carbon masts that have been designed of late, stayed or not. 
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<SPAN style="FONT-FAMILY: Arial; COLOR: black; FONT-SIZE:
10pt">From my knowledge to build a mast for that rig which does what
you suggest it would result in a very heavy spar, the resulting design
spiral from a heavier rig we both know.  I suggestion is that it is better to,
yes design it to minimise fall-off to leeward, but within reason in terms of
mast mass or sectional area, then after that it is up to design the sail to
work with the bend that remains rather than fight it.  You end up with a
lighter boat which should give you back some of what you may have lost. 
If I am being really honest, given its a sealed mast, and its unstayed why
they do not have a tube luff like the moths I don't know, if that is in the
depth of the other thread let me know and I'll trawl back through and
read it.  I think they have missed a great trick there.  One of my past
projects looked into the feasibility of putting something equating to a
tube luff on stayed rigs, but I never quite got round to finishing it, as it
mutated into looking at putting wing sails on IACC yachts (I wasn't too far
off the mark in the end).  </SPAN>

<SPAN style="FONT-FAMILY: Arial; COLOR: black; FONT-SIZE:
10pt">What made me question you level of knowledge of fluid mechanics
is you mention of laminar flow foils, this is my pet hate, below the
waterline this phenomenon is practically useless, rigs yes, air's viscosity is
low enough for it to be a factor, but in water, its irrelevant unless you
have the smoothest surface in history and you are travelling very slowly. 
The maths and anecdotal evidence both back this up.  The confusion is
that at very high speeds similar foil sections to 'laminar flow sections'
become the most efficient but for subtlely different reasons. 
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<SPAN style="FONT-FAMILY: Arial; COLOR: black; FONT-SIZE:
10pt">As I have suggested before I am genuinely interested in meeting
up with you at some point and discussing all of this, believe it or not I do
have a healthy level of respect for you, there are just certain things I
disagree with, probably as a result of the different backgrounds we have. 
I would love to take you for a sail in the B14, and to try the Alto for us to
see what each others weapon of choice is like, I could come down for a
weekend and we could argue fluids mechanics over a few pints on the
saturday night.  The offer still stands.  </SPAN>

<SPAN style="FONT-FAMILY: Arial; COLOR: black; FONT-SIZE: 10pt">I
hope thins clears things up, I am trying not to let this discussion get
personal, badly-granted, but trying.  </SPAN>

<SPAN style="FONT-FAMILY: Arial; COLOR: black; FONT-SIZE:
10pt">Phil</SPAN>