[Rhodes22-list] Sailing Upwind

Rick sloopblueheron at gmail.com
Wed Aug 25 10:52:17 EDT 2010 

Lee,

The Racing Rules of Sailing exclude GPS.  But most of the "deep water" races
that are point-to-point on Lake Erie make a change to to the rules to allow
GPS.   And it is just for the reason that most boats sail faster broad to
the wind than close.  In other words, sailing broad off the rhumb line
course, then tacking in for the finish, will often get you there faster than
sailing close hauled along the rhumb line.

It all has to do with the lift resulting from the difference in air pressure
between the inner and outer surfaces of the sail.  On a broad reach, the
lateral direction of the true wind against the inner surface of the sail
creates more high pressure on the inner surface.  This results in a greater
pressure differential and better sustained sail shape than any other point
of sail.

Rick

On Wed, Aug 25, 2010 at 9:47 AM, Leland <LKUHN at cnmc.org> wrote:

>
> Rick,
>
> My wife claims I can make wind that's very apparent.
>
> Probably a poor choice of words on my part.  This is more what I meant:
>
> >From Steve Colgate:  The fourth point was that when a boat is reaching or
> beating, the apparent wind is of greater velocity than the true wind. You
> are, in effect, "making your own wind." In iceboating this is an important
> part of the resulting high speeds. Some iceboats, for instance, can reach
> speeds five to six times the speed of the wind and can attain speeds of 120
> knots in 24 knots of wind. The faster the boat goes, the higher the wind
> velocity it creates.
>
>
> http://www.sailnet.com/forums/learning-sail-articles/18848-understanding-apparent-wind.html
>
> http://www.sailnet.com/forums/learning-sail-articles/18848-understanding-apparent-wind.html
>
> I just found a link that stated your VMG will be better going fast off the
> wind instead of slow into the wind, which is just the opposite of what I
> thought.  I wonder if racers are allowed to use GPSs and calculators?
>
> Lee
>
>
>
> Blue Heron wrote:
> >
> > Lee,
> >
> > You don't "make" apparent wind.  It is no different than when you stick
> > your
> > head out of a moving car.  If a car, or boat, heads into a wind, it feels
> > stronger than when the wind is behind you.
> >
> > Rick
> >
> > On Tue, Aug 24, 2010 at 11:51 AM, KUHN, LELAND <LKUHN at cnmc.org> wrote:
> >
> >> Ben,
> >>
> >> Glad to hear it worked.  I'm typically trying to make headway in heavier
> >> winds but over the weekend I was trying to do so in about a five knot
> >> wind.  I had the Genoa sheets run between the shrouds and the board down
> >> but only seemed to be doing about 70 degrees into the wind.  I shifted
> >> my weight to the leeward side of the boat to get more heel so the boat
> >> would get into the groove and go faster.  I not only picked up speed but
> >> significantly increased my windward performance.  It's probably common
> >> sense for most sailors but it was another "Aha!" moment for me.
> >>
> >> I'm still struggling with wind VMG (velocity made good).  I understand
> >> the theory but don't know how you'd easily determine it without a GPS
> >> with VMG functionality.  Too much into the wind and you're going too
> >> slow and too much off the wind and you're going too far out of the way.
> >> You'd think that reaching into the wind just before you start slowing
> >> down would be best but that's not what the polar diagrams indicate.  Our
> >> light displacement boats pick up so much speed when we come off the wind
> >> that it seems like we must have a better VMG by having more speed.
> >>
> >> I'm not sure but I think the apparent wind is the problem.  The faster
> >> you go into the wind the more apparent wind you create which allows you
> >> to go even faster, but the apparent wind also pushes you away from the
> >> true wind.
> >>
> >> >From the J/Boat website:  A J/120 sailing at 7.2 knots, 38 degrees off
> >> the true wind (25 degrees apparent wind angle), makes good a velocity
> >> (VMG) of 5.7 knots straight into the wind. This is 15% faster than a
> >> boat doing 7 knots at a 45 degree true wind angle.
> >>
> >> So I think with our boats we still make better VMG by slowing down into
> >> the wind than by speeding up off the wind.  I just can't figure out how
> >> much speed to sacrifice.
> >>
> >> Maybe I just need to have fun, use the motor when I need it, and
> >> fugetaboudit.
> >>
> >> Lee
> >> 1986 Rhodes22  AT EASE
> >> Kent Island, MD
> >>
> >>
> >>
> >> -----Original Message-----
> >> From: rhodes22-list-bounces at rhodes22.org
> >> [mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of BenCittadino
> >> Sent: Tuesday, August 24, 2010 11:45 AM
> >> To: rhodes22-list at rhodes22.org
> >> Subject: Re: [Rhodes22-list] Sailing Upwind
> >>
> >>
> >> Stephen;
> >>
> >> I just ran the sheets inside the outermost shrouds and brought them
> >> through
> >> the pulleys and winches on the gunwhales. I think I need some shroud
> >> "guards" or "rollers" before I bring the Genny back past the mast by
> >> that
> >> route, but I was definitely surprised how much difference that seemingly
> >> small adjustment made in upwind sailing.
> >>
> >> BenC
> >>
> >> Stephen Staum wrote:
> >> >
> >> > Ben,
> >> >
> >> > Did you go just inside the shrouds or to the inner track as well?
> >> >
> >> > Stephen Staum
> >> > 87 R22, Carol Lee
> >> >
> >> > Sent from my iPhone
> >> >
> >> > On Aug 23, 2010, at 6:55 PM, "Benjamin Cittadino"
> >> <BCittadino at dcs-law.com
> >> >  > wrote:
> >> >
> >> >> I had two days in a row on Sandy Hook Bay in NJ this weekend, and I
> >> >> want
> >> >> to report that I had a pleasing experience by "finally" re-routing
> >> the
> >> >> Jib (175 Genny) sheets inside the outer shrouds to try for better
> >> >> upwind
> >> >> sailing. I have to say that I didn't expect much difference, but I
> >> was
> >> >> delighted to get inside 45 degrees at last. I obviously didn't let
> >> the
> >> >> Genny out to the full 175, but at 100 we flew along and I felt like I
> >> >> could make real headway upwind. I had delayed trying the new route
> >> for
> >> >> the sheets because I thought the sail would get all hung up in the
> >> >> shrouds, but it's become no big deal. Try it, you'll like it.
> >> >>
> >> >>
> >> >>
> >> >> BenCittadino
> >> >>
> >> >> S/V Susan Kay ('93 recycled '08)
> >> >>
> >> >>
> >> >>
> >> >> PS-Could not connect to Nabble today??!!
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
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> >> >
> >>
> >> --
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> >>
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> --
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>
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