[Rhodes22-list] How fast does your R22 go?

Sun Jan 25 17:39:46 EST 2009

Love that video saw it a year or so ago when I began my decent into sailing
madness


Blue Heron wrote:
> 
> Is there an R22 in this?
> 
> http://www.youtube.com/watch?v=nDToL593cmU
> 
> Rick
> 
> On Sun, Jan 25, 2009 at 4:21 PM, Ronald Lipton
> <ronald.lipton at gmail.com>wrote:
> 
>> Some gratuitous physics (mostly from the "Symmetry of Sail").
>>
>> Hull speed occurs when the speed of the wave front generated by the
>> bow wave has the same wavelength as the boat.  At that point the
>> boat has to "climb it's own wave".  Wavelength and velocity for a
>> a water wave are related by V = sqrt(gL/2pi).
>> Most of you know that, but there is an exception:
>>
>>  In water which is shallow compared to the
>> wavelengh wave propagation is dominated by the depth - and for the
>> longer wavelengths  V = sqrt(gD) (D is the Depth) or
>> V(knots) = 6.2*sqrt(D(meters).  This means that the effective "depth
>> speed" in shallow water is much larger than that at larger depth for a
>> small boat.
>> This also means that all waves, of whatever wavelength,  generated below
>> "depth speed" move ahead of the boat, decreasing wave friction.  However
>> the bow wave at "depth speed" would be enormous.
>>
>> Wave drag is one component of the drag forces on a boat. The other
>> major forces are skin frictional resistance and vortex drag.  Skin
>> friction appears
>> to dominate until about 2/3 of hull speed.  Wave drag goes "through the
>> roof" with
>> respect to the other drag forces as the nominal hull speed is exceeded.
>>
>> Ron
>>
>>
>> Eric Nelson wrote:
>> > Imagine my suprise to see this. GPS was reading between 8.5 and 9 MPH.
>> Was
>> > lots of fun since the slightest tug on the Main Sheet would send the
>> boat
>> > heeling, and my wife and daughter screaming. Only lasted about 5
>> minutes,
>> > but long enough to snap this photo.
>> > ----- Original Message -----
>> > From: "TN Rhodey" <tnrhodey at gmail.com>
>> > To: "The Rhodes 22 Email List" <rhodes22-list at rhodes22.org>
>> > Sent: Sunday, January 25, 2009 5:20 AM
>> > Subject: Re: [Rhodes22-list] How fast does your R22 go?
>> >
>> >
>> >
>> >> Sailing on lake/river I can motor 6 knots with my 6 hp motor wide
>> open.
>> >> This
>> >> may seem hard to believe but I have toppped 7 knots a couple of times
>> >> under
>> >> sail. This speed was sustained for periods of around 5 minutes or so
>> and
>> >> was
>> >> on a run that turned into a reach that turned into a broach.
>> >>
>> >> The first time happened in a race under very windy conditions (20+). I
>> >> posted this story 6 or so years ago. It was in January with temps in
>> the
>> >> 30s
>> >> and snow on the ground/. The conditions were such that we only had 7
>> boats
>> >> in the race. Two pulled out right after the start. A Catalina 30
>> shredded
>> >> their main. A husband/wife crew didn'tt think their marriage would
>> survive
>> >> the race. We were now down to 5 boats.
>> >>
>> >> I was sailing my R22 single handed with with 60% furled main and a 125
>> >> jib.
>> >> The RC didn't want to mess with buoys because it was so cold. The race
>> >> course was around Half Moon Island and back through the starting gate.
>> It
>> >> was upwind towards the island. The wind was really blowing, the sky
>> was
>> >> gray, and then it started snowing. I was over powered several times
>> and
>> >> had
>> >> a hard time keeping flat. By staying in the shallow side in the lee of
>> the
>> >> island I was able to shorten the course and find some calmer weather.
>> I
>> >> decided to unfurl the main to take advantage of the lull.
>> >>
>> >> Once crossing the island I jibed to turn back towards the finish line.
>> I
>> >> was
>> >> no longer in the lee and the boat took off like a rocket. My GPS was
>> >> showing
>> >> a steady 7 plus knots for minutes at a time with occasional bursts
>> going
>> >> over 9. It was not a smooth ride as the boat kept wanting to head up.
>> >> Finally the boat was over powered and broached. Rudder control was
>> useless
>> >> at this point and I rounded up heeling hard.. I furled the main back
>> in
>> >> and
>> >> ran the rest of the way to the line chugging along at 6 - 7 knots
>> steady.
>> >> Note this is measured speed over ground. I do not have knot meter. I
>> can't
>> >> remember the results but i remember I finished 4 out of 5. I beat a
>> >> Newport
>> >> 28 before they corrected the time! I think I corrected to 2 or 3.
>> >>
>> >> Remember hull speed is only theoretical. The RC measured wind speed
>> that
>> >> day
>> >> at 18-23 with gusts measured over 30.
>> >>
>> >> Fair Winds,
>> >>
>> >> Wally
>> >>
>> >> On Sun, Jan 25, 2009 at 7:36 AM, Metaphor <mwager at bluecrab.org> wrote:
>> >>
>> >>
>> >>> I had it up to about 70 on the way to the put-in ramp, but I got kind
>> of
>> >>> scared when it started heeling too much around the turns, so I backed
>> it
>> >>> down to the 50 mph speed limit...
>> >>>
>> >>> --
>> >>> View this message in context:
>> >>>
>> http://www.nabble.com/How-fast-does-your-R22-go--tp21641761p21651283.html
>> >>>  Sent from the Rhodes 22 mailing list archive at Nabble.com.
>> >>>
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