{Stus-List} keel reduction

rspence7 rspence7 at cox.net
Mon Feb 4 23:47:11 EST 2008


Sorry you doubt me!  Perchance there were too many Bourbon molecules holding 
on to my ice cubes!

My point in the post was not to try to favor a winged keel over any other 
type, but to point out that after the Aussie winged keel, hundreds upon 
hundreds of $ millions were spent on fluid dynamics; kabillions of bytes of 
computer data were analyzed, tank tests exploded, and very suddenly, speed 
potential of new boats with new "super keels"  and high tech sail-cloth made 
our older boats very comparatively slower:
Commercial aircraft suddenly realized the effect of tip vortex, and sported 
winglets.
I sincerely believe that the Aussie keel brought about very significant 
change in the technical design aspects of our sport.

Meter boats have always been beholden to the interaction of the parameters 
of the outdated design criteria;  suddenly the Aussies found out how to 
finesse these interconnected LOA; LWL; sail area; displacement; draft; beam; 
P; J; E; etc., etc. rules with a breakthrough.  All equalled a faster boat - 
for that rule!

Breakthroughs happen!

"America" did that in the mid 1800's; Herreschoff did that at the turn of 
the century and into the '30's; S&S design "fatso" Finnisterre did that in 
the '50's; Fiberglass did that in the '60's; C&C did that in the early 
'70's; the Aussies did that in the late '70's; the computer took over in the 
'80's to today.

Our "moderate" 70's to early 80's C&C's were probably the culmination of 
what what was the ultimate in fast - with comfortable - designs.

Today's super wide transoms tilt the entire heeling planform forward, as the 
fat aft sections add so much aft heeling incremental bouyancy, dipping the 
bows into the onrushing water. This then needs more plumb bows, to add to 
forward bouyancy; all resulting in longer and flat, yet pounding and wet 
central hull forms.
Faster, yes; Comfortable; no; Better? - your call!

Roger


----- Original Message ----- 
From: <ckilgour at sympatico.ca>
To: <cnc-list at cnc-list.com>
Sent: Monday, February 04, 2008 5:35 PM
Subject: Re: {Stus-List} keel reduction


> Sure it is... Right...
>
> CK
>
>>From: "rspence7" <rspence7 at cox.net>
>>Reply-To: cnc-list at cnc-list.com
>>To: <cnc-list at cnc-list.com>
>>Subject: Re: {Stus-List} keel reduction
>>Date: Sun, 3 Feb 2008 16:01:52 -0500
>>
>>Oops, that's supposed to read "Kicking"  freudian slip!
>>
>>Roger
>>----- Original Message -----
>>From: "rspence7" <rspence7 at cox.net>
>>To: <cnc-list at cnc-list.com>
>>Sent: Sunday, February 03, 2008 2:35 PM
>>Subject: Re: {Stus-List} keel reduction
>>
>>
>> > Peter,
>> > All of your ruminations on keel depth are probably accurate, but the
>> > biggest
>> > changes in keel thinking came from the Aussies licking Dennis Conner's
>>ass
>> > in the America's Cup with their winged keel.
>> >
>> > More NACA keel development came from that event than probably all
>>recorded
>> > history up to that point!
>> >
>> > Roger
>> >
>> > ----- Original Message -----
>> > From: "Peter Deppisch" <peter.deppisch at sympatico.ca>
>> > To: <cnc-list at cnc-list.com>
>> > Sent: Sunday, February 03, 2008 12:21 PM
>> > Subject: Re: {Stus-List} keel reduction
>> >
>> >
>> >>I have seen this done at Bayfield Marine Services.  They take a 
>> >>chainsaw
>> >> and cut-off the keel at the desired depth and then bolt on two half
>> >> bulbs and fair and paint and you would think that it was designed that
>> >> way.
>> >>
>> >> Basically keel depth gives you upwind performance.  If you look at the
>> >> Cruising Club of America (CCA) boats designed in the '60's they all 
>> >> had
>> >> shallow draft in relationship to length or a keel/centreboard
>> >> configuration.  The C&C designed Corvette31, keel/centreboard, or the
>> >> C&C Redwing 30 with a draft of 4' 6".  I think C&C may have looked at
>> >> the Hinckley Bermuda 40 to see what was current in sailboat design at
>> >> the time.  My opinion anyway.
>> >>
>>http://www.yachtworld.com/core/listing/boatFullDetails.jsp;jsessionid=agSv0fmmhXQh?boat_id=1567116&ybw=&units=Feet&currency=USD&access=Public&listing_id=38184&url=
>> >>
>> >> In the '70's the draft increased.  The  C&C 35 MK I has a draft of 5'
>> >> 3", my C&C 35 MK II draws 5' 6".  The Viking 33/34 draws 5' 6" and 6'
>> >> respectively and the C&C 35 MK III has a draft of 6' 6", I think.
>> >>
>> >> The winged keel reduces draft and is supposed to make up for loss of
>> >> upwind performance because of lack of keel depth.
>> >>
>> >> A long time ago I read that a boat needs to be able to claw of a lee
>> >> shore under sail alone.
>> >>
>> >> Peter
>> >> S/V Tangerine
>> >>
>> >> cscheaffer at comcast.net wrote:
>> >>> I'm considering the same thing.
>> >>> Checkout the new website at:
>> >>>
>> >>> marskeel.com
>> >>>
>> >>> Go to Services, Keel Reduction, etc
>> >>> There are some great photos and an explanation of the weight increase
>> >>> involved.  The waterline will be a little higher.  I wonder what the
>> >>> yard charges?
>> >>>
>> >>> Chuck
>> >>> C&C 34R
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>     -------------- Original message --------------
>> >>>     From: "Bob MacKenzie" <mackbob at mnsi.net>
>> >>>
>> >>>     I'm looking into the possibility of cutting 16 inches off the 
>> >>> keel
>> >>>     of my C&C 34 (1978) to cope with lowering water levels in Lake 
>> >>> St.
>> >>>     Clair and Lake Erie. This wouldreduce my draft to five feet. 
>> >>> Local
>> >>>     boatyard has checkede with Mars metals (wwhich cast original
>> >>>     keels) and it has worked out how much lead I will have to add to
>> >>>     maintain current stability. They will double check templates for
>> >>>     keel, then cast two pods to bolt through keel. They had figures
>> >>>     right at hand, so obviously they have done this before. Anyone
>> >>>     have any first-hand experience with this, or have any comments? 
>> >>> (I
>> >>>     gave up racing five years ago, and have already added a
>> >>>     self-tacking jib, so I'm thinking from a cruising point of view.
>> >>>     Bob MacKenzie
>> >>>
>> >>>
>> >>>
>>------------------------------------------------------------------------
>> >>>
>> >>> Subject:
>> >>> {Stus-List} Fw: keel modifications
>> >>> From:
>> >>> "Bob MacKenzie" <mackbob at mnsi.net>
>> >>> Date:
>> >>> Sun, 3 Feb 2008 02:05:47 +0000
>> >>> To:
>> >>> "Cnc-List at Cnc-List.Com" <cnc-list at cnc-list.com>
>> >>>
>> >>> To:
>> >>> "Cnc-List at Cnc-List.Com" <cnc-list at cnc-list.com>
>> >>>
>> >>>
>> >>> _______________________________________________
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>>------------------------------------------------------------------------
>> >>>
>> >>> No virus found in this incoming message.
>> >>> Checked by AVG.
>> >>> Version: 7.5.516 / Virus Database: 269.19.19/1256 - Release Date:
>> >>> 02/02/2008 1:50 PM
>> >>>
>> >>
>> >> --
>> >> Paraphrasing Pogo:
>> >> We are like Nero - fiddling while the Earth burns!
>> >> Website:
>> >> http://www3.sympatico.ca/peter.deppisch
>> >> http://peter.deppisch.googlepages.com/
>> >>
>> >>
>> >> _______________________________________________
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