Re: Stus-List downwind polars

[Ronald B. Frerker via CnC-List]

 The polars I've seen for a number of boats all seem to indicate that sailing 
off DDW will be faster especially in winds speeds from around five up.  One can 
tell at a glance by looking for the "bulge" in the curve on the plotted part of 
the polars.  Below that wind speed I don't know how reliable the charts are.  I 
believe most are calculated based on drawings and build parameters and not 
actual data.   The other beauty of sailing off DDW is one doesn't get the "rock 
& roll" in higher winds with the chute up.RonWild CheriC&C 30-1STL

On Sunday, July 1, 2018, 6:25:22 AM CDT, Josh Muckley via CnC-List 
 wrote:  
 
 Its not a matter of whether or not the boat is faster.  Its a matter of 
achieving the highest velocity made good.  In my experience even on courses 
where the mark is directly down wind the symmetrical spinnaker boats will keep 
the wind slightly to one side.  Yes you may have to gybe but the overall speed 
(vmg or cs) is faster.  As part of this decision you have to consider crew 
competence, time until next, and your own experience with the boat.
Josh MuckleyS/V Sea Hawk1989 C&C 37+Solomons, MD 





On Sat, Jun 30, 2018, 6:54 PM David Knecht via CnC-List  
wrote:

I guess my real question is whether the boat is faster dead downwind with the 
whisker pole or tacking downwind at the polar angle optimum.  I have always 
used the whisker pole and the shorter distance, and have not yet tried the 
other route.  Has anyone tested this themselves?  Dave




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Re: Stus-List downwind polars

[Josh Muckley via CnC-List]

Its not a matter of whether or not the boat is faster.  Its a matter of
achieving the highest velocity made good.  In my experience even on courses
where the mark is directly down wind the symmetrical spinnaker boats will
keep the wind slightly to one side.  Yes you may have to gybe but the
overall speed (vmg or cs) is faster.  As part of this decision you have to
consider crew competence, time until next, and your own experience with the
boat.

Josh Muckley
S/V Sea Hawk
1989 C&C 37+
Solomons, MD





On Sat, Jun 30, 2018, 6:54 PM David Knecht via CnC-List <
cnc-list@cnc-list.com> wrote:

> I guess my real question is whether the boat is faster dead downwind with
> the whisker pole or tacking downwind at the polar angle optimum.  I have
> always used the whisker pole and the shorter distance, and have not yet
> tried the other route.  Has anyone tested this themselves?  Dave
>
> On Jun 30, 2018, at 12:17 PM, Ronald B. Frerker via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> Polars presume a spinnaker at the crossover point where the chute is
> faster than jib & main.
> As for downwind speed, the Marchaj (sp?) book has data to back the old
> theory that if you reverse your best beat upwind, you will be going the
> same speed downwind.
> When the wind speed increases to the point of reefing or smaller jibs, all
> bets are off on that theory.  Then wing & wing will often be faster.
> Ron
> Wild Cheri
> C&C 30-1
> STL
>
> -Original Message-
> From: David Knecht via CnC-List 
> To: CnC CnC discussion list 
> Cc: David Knecht 
> Sent: Sat, Jun 30, 2018 7:48 am
> Subject: Stus-List downwind polars
>
> The polars for my boat predict an optimal downwind speed at an angle
> around 145° true.   Does anyone know what assumptions are made in this
> prediction about spinnakers and whisker poles?  I race non-spinnaker and
> often on windward-leeward courses so we are often dead downwind and the
> whisker pole makes a huge difference going downwind wing on wing.  I am
> wondering if the polars take this into account.  Dave
>
> Aries
> 1990 C&C 34+
> New London, CT
>
> 
>
> ___
>
> Thanks everyone for supporting this list with your contributions. Each and
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>
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> Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --   https://www.paypal.me/stumurray
>
>
> Dr. David Knecht
> Professor of Molecular and Cell Biology
> University of Connecticut
> 91 N. Eagleville Rd.
> Storrs, CT 06269-3125
>
>
>
> ___
>
> Thanks everyone for supporting this list with your contributions.  Each
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>
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Re: Stus-List downwind polars

[Rod Stright via CnC-List]

It really depends upon the wind strength and conditions.  Sometimes in light 
air dead downwind doesn’t work very well as the boat sails over itself and 
stalls, in these situations you may make better speed reaching, it all depends 
upon your VMG.



Rod

C&C 99

2004



From: CnC-List  On Behalf Of David Knecht via 
CnC-List
Sent: June-30-18 7:54 PM
To: CnC CnC discussion list 
Cc: David Knecht 
Subject: Re: Stus-List downwind polars



I guess my real question is whether the boat is faster dead downwind with the 
whisker pole or tacking downwind at the polar angle optimum.  I have always 
used the whisker pole and the shorter distance, and have not yet tried the 
other route.  Has anyone tested this themselves?  Dave



On Jun 30, 2018, at 12:17 PM, Ronald B. Frerker via CnC-List 
mailto:cnc-list@cnc-list.com> > wrote:



Polars presume a spinnaker at the crossover point where the chute is faster 
than jib & main.

As for downwind speed, the Marchaj (sp?) book has data to back the old theory 
that if you reverse your best beat upwind, you will be going the same speed 
downwind.

When the wind speed increases to the point of reefing or smaller jibs, all bets 
are off on that theory.  Then wing & wing will often be faster.

Ron

Wild Cheri

C&C 30-1

STL





-Original Message-
From: David Knecht via CnC-List mailto:cnc-list@cnc-list.com> >
To: CnC CnC discussion list mailto:CnC-List@cnc-list.com> >
Cc: David Knecht mailto:davidakne...@gmail.com> >
Sent: Sat, Jun 30, 2018 7:48 am
Subject: Stus-List downwind polars

The polars for my boat predict an optimal downwind speed at an angle around 
145° true.   Does anyone know what assumptions are made in this prediction 
about spinnakers and whisker poles?  I race non-spinnaker and often on 
windward-leeward courses so we are often dead downwind and the whisker pole 
makes a huge difference going downwind wing on wing.  I am wondering if the 
polars take this into account.  Dave



Aries

1990 C&C 34+

New London, CT






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https://www.paypal.me/stumurray



Dr. David Knecht

Professor of Molecular and Cell Biology

University of Connecticut

91 N. Eagleville Rd.

Storrs, CT 06269-3125









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Re: Stus-List downwind polars

[Joel Aronson via CnC-List]

 In light air, dead downwind will be faster. Set your way point for dead
downwind and measure your VMG both ways to find out when it no longer makes
sense

Joel

On Sat, Jun 30, 2018 at 6:54 PM David Knecht via CnC-List <
cnc-list@cnc-list.com> wrote:

> I guess my real question is whether the boat is faster dead downwind with
> the whisker pole or tacking downwind at the polar angle optimum.  I have
> always used the whisker pole and the shorter distance, and have not yet
> tried the other route.  Has anyone tested this themselves?  Dave
>
> On Jun 30, 2018, at 12:17 PM, Ronald B. Frerker via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> Polars presume a spinnaker at the crossover point where the chute is
> faster than jib & main.
> As for downwind speed, the Marchaj (sp?) book has data to back the old
> theory that if you reverse your best beat upwind, you will be going the
> same speed downwind.
> When the wind speed increases to the point of reefing or smaller jibs, all
> bets are off on that theory.  Then wing & wing will often be faster.
> Ron
> Wild Cheri
> C&C 30-1
> STL
>
> -Original Message-
> From: David Knecht via CnC-List 
> To: CnC CnC discussion list 
> Cc: David Knecht 
> Sent: Sat, Jun 30, 2018 7:48 am
> Subject: Stus-List downwind polars
>
> The polars for my boat predict an optimal downwind speed at an angle
> around 145° true.   Does anyone know what assumptions are made in this
> prediction about spinnakers and whisker poles?  I race non-spinnaker and
> often on windward-leeward courses so we are often dead downwind and the
> whisker pole makes a huge difference going downwind wing on wing.  I am
> wondering if the polars take this into account.  Dave
>
> Aries
> 1990 C&C 34+
> New London, CT
>
> 
>
> ___
>
> Thanks everyone for supporting this list with your contributions. Each and
> every one is greatly appreciated. If you want to support the list - use
> PayPal to send contribution -- https://www.paypal.me/stumurray
>
> ___
>
> Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --  https://www.paypal.me/stumurray
>
> ___
>
>
>
> Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --   https://www.paypal.me/stumurray
>
>
> Dr. David Knecht
> Professor of Molecular and Cell Biology
> University of Connecticut
> 91 N. Eagleville Rd.
> Storrs, CT 06269-3125
>
>
>
> ___
>
> Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --   https://www.paypal.me/stumurray
>
> --
Joel
301 541 8551
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Re: Stus-List downwind polars

[David Knecht via CnC-List]

I guess my real question is whether the boat is faster dead downwind with the 
whisker pole or tacking downwind at the polar angle optimum.  I have always 
used the whisker pole and the shorter distance, and have not yet tried the 
other route.  Has anyone tested this themselves?  Dave

> On Jun 30, 2018, at 12:17 PM, Ronald B. Frerker via CnC-List 
>  wrote:
> 
> Polars presume a spinnaker at the crossover point where the chute is faster 
> than jib & main.
> As for downwind speed, the Marchaj (sp?) book has data to back the old theory 
> that if you reverse your best beat upwind, you will be going the same speed 
> downwind.
> When the wind speed increases to the point of reefing or smaller jibs, all 
> bets are off on that theory.  Then wing & wing will often be faster.
> Ron
> Wild Cheri
> C&C 30-1
> STL
> 
> 
> -Original Message-
> From: David Knecht via CnC-List 
> To: CnC CnC discussion list 
> Cc: David Knecht 
> Sent: Sat, Jun 30, 2018 7:48 am
> Subject: Stus-List downwind polars
> 
> The polars for my boat predict an optimal downwind speed at an angle around 
> 145° true.   Does anyone know what assumptions are made in this prediction 
> about spinnakers and whisker poles?  I race non-spinnaker and often on 
> windward-leeward courses so we are often dead downwind and the whisker pole 
> makes a huge difference going downwind wing on wing.  I am wondering if the 
> polars take this into account.  Dave
> 
> Aries
> 1990 C&C 34+
> New London, CT
> 
> 
> 
> ___
> 
> Thanks everyone for supporting this list with your contributions. Each and 
> every one is greatly appreciated. If you want to support the list - use 
> PayPal to send contribution -- https://www.paypal.me/stumurray 
> <https://www.paypal.me/stumurray>
> 
> ___
> 
> Thanks everyone for supporting this list with your contributions.  Each and 
> every one is greatly appreciated.  If you want to support the list - use 
> PayPal to send contribution --  https://www.paypal.me/stumurray 
> <https://www.paypal.me/stumurray>
> 
> ___
> 
> Thanks everyone for supporting this list with your contributions.  Each and 
> every one is greatly appreciated.  If you want to support the list - use 
> PayPal to send contribution --   https://www.paypal.me/stumurray 
> <https://www.paypal.me/stumurray>
Dr. David Knecht
Professor of Molecular and Cell Biology
University of Connecticut   
91 N. Eagleville Rd.
Storrs, CT 06269-3125



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Re: Stus-List downwind polars

[Ronald B. Frerker via CnC-List]

 Polars presume a spinnaker at the crossover point where the chute is faster 
than jib & main.As for downwind speed, the Marchaj (sp?) book has data to back 
the old theory that if you reverse your best beat upwind, you will be going the 
same speed downwind.When the wind speed increases to the point of reefing or 
smaller jibs, all bets are off on that theory.  Then wing & wing will often be 
faster.RonWild CheriC&C 30-1STL

-Original Message-
From: David Knecht via CnC-List 
To: CnC CnC discussion list 
Cc: David Knecht 
Sent: Sat, Jun 30, 2018 7:48 am
Subject: Stus-List downwind polars

The polars for my boat predict an optimal downwind speed at an angle around 
145° true.   Does anyone know what assumptions are made in this prediction 
about spinnakers and whisker poles?  I race non-spinnaker and often on 
windward-leeward courses so we are often dead downwind and the whisker pole 
makes a huge difference going downwind wing on wing.  I am wondering if the 
polars take this into account.  Dave
Aries1990 C&C 34+New London, CT

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Re: Stus-List downwind polars

[Randy Stafford via CnC-List]

Hi David,

One of the features of the SailTimer App and Wind Instrument 
(http://www.sailtimerapp.com , 
http://sailtimerwind.com ) that attracted me to buy 
them is that the app can create polar diagrams for your specific boat and 
specific set of sails you're flying.  So you can have a polar for sailing 
wing-and-wing downwind, and a different polar for sailing spinnaker downwind.  
And each polar will be true to your boat’s displacement, propeller, bottom 
condition, sail quality, etc., not general to the make under unknown 
assumptions.

I’ve experimented with the feature, trying to create different polars for 
different headsails I use.  To be truthful I haven’t completed the exercise - 
you have to sail all the angles in multiple wind speeds with each sail 
configuration.  But I thought it was a cool feature, and it helped convince me 
to buy the system.

Cheers,
Randy Stafford
S/V Grenadine
C&C 30-1 #7
Ken Caryl, CO

> On Jun 30, 2018, at 5:47 AM, David Knecht via CnC-List 
>  wrote:
> 
> The polars for my boat predict an optimal downwind speed at an angle around 
> 145° true.   Does anyone know what assumptions are made in this prediction 
> about spinnakers and whisker poles?  I race non-spinnaker and often on 
> windward-leeward courses so we are often dead downwind and the whisker pole 
> makes a huge difference going downwind wing on wing.  I am wondering if the 
> polars take this into account.  Dave
> 
> Aries
> 1990 C&C 34+
> New London, CT
> 
> 
> 
> ___
> 
> Thanks everyone for supporting this list with your contributions.  Each and 
> every one is greatly appreciated.  If you want to support the list - use 
> PayPal to send contribution --   https://www.paypal.me/stumurray
> 

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Re: Stus-List downwind polars

[Charlie Nelson via CnC-List]

I think most polars assume a kite will be used downwind.


cenel...@aol.com




-Original Message-
From: David Knecht via CnC-List 
To: CnC CnC discussion list 
Cc: David Knecht 
Sent: Sat, Jun 30, 2018 7:48 am
Subject: Stus-List downwind polars


The polars for my boat predict an optimal downwind speed at an angle around 
145° true.   Does anyone know what assumptions are made in this prediction 
about spinnakers and whisker poles?  I race non-spinnaker and often on 
windward-leeward courses so we are often dead downwind and the whisker pole 
makes a huge difference going downwind wing on wing.  I am wondering if the 
polars take this into account.  Dave



Aries
1990 C&C 34+
New London, CT





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Re: Stus-List downwind polars

[Indigo via CnC-List]

The downwind polars on the J109 I race on regularly definitely assume spinnaker 
use. The Class jib is barely more than 100% (maybe 105%) and if going downwind 
jib and main only we’d never finish!  The polars we steer to give precise wind 
angles depending on true wind speed. The lighter the wind, the hotter angle we 
have to sail. Doubt it is any different with a symmetrical kite. 

--
Jonathan
Indigo C&C 35III
SOUTHPORT CT

> On Jun 30, 2018, at 08:24, Edd Schillay via CnC-List  
> wrote:
> 
> David,
> 
> I’m pretty sure polars are for standard jib and main configuration and do not 
> account for wing-on-wing pole use or spinnaker use. 
> 
> All the best, 
> 
> Edd
> 
> ---
> Edd M. Schillay
> Captain of the Starship Enterprise 
> C&C 37+ | Sail No: NCC-1701-B
> City Island, New York
> www.StarshipSailing.com
> ---
> 914.774.9767   | Mobile
> ---
> Sent via iPhone X
> iPhone. iTypos. iApologize
> 
> 
> On Jun 30, 2018, at 7:47 AM, David Knecht via CnC-List 
>  wrote:
> 
> The polars for my boat predict an optimal downwind speed at an angle around 
> 145° true.   Does anyone know what assumptions are made in this prediction 
> about spinnakers and whisker poles?  I race non-spinnaker and often on 
> windward-leeward courses so we are often dead downwind and the whisker pole 
> makes a huge difference going downwind wing on wing.  I am wondering if the 
> polars take this into account.  Dave
> 
> Aries
> 1990 C&C 34+
> New London, CT
> 
> 
> 
> ___
> 
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> every one is greatly appreciated.  If you want to support the list - use 
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> 
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Re: Stus-List downwind polars

[Edd Schillay via CnC-List]

David,

I’m pretty sure polars are for standard jib and main configuration and do not 
account for wing-on-wing pole use or spinnaker use. 

All the best, 

Edd

---
Edd M. Schillay
Captain of the Starship Enterprise 
C&C 37+ | Sail No: NCC-1701-B
City Island, New York
www.StarshipSailing.com
---
914.774.9767   | Mobile
---
Sent via iPhone X
iPhone. iTypos. iApologize


On Jun 30, 2018, at 7:47 AM, David Knecht via CnC-List  
wrote:

The polars for my boat predict an optimal downwind speed at an angle around 
145° true.   Does anyone know what assumptions are made in this prediction 
about spinnakers and whisker poles?  I race non-spinnaker and often on 
windward-leeward courses so we are often dead downwind and the whisker pole 
makes a huge difference going downwind wing on wing.  I am wondering if the 
polars take this into account.  Dave

Aries
1990 C&C 34+
New London, CT



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Re: Stus-List downwind polars

[Josh Muckley via CnC-List]

I think the assumption is that downwind you'll only ever go as fast as the
wind.  Maybe I'm thinking about it wrong.

Josh Muckley
S /V Sea Hawk
1989 C&C 37+
Solomons, MD



On Sat, Jun 30, 2018, 7:48 AM David Knecht via CnC-List <
cnc-list@cnc-list.com> wrote:

> The polars for my boat predict an optimal downwind speed at an angle
> around 145° true.   Does anyone know what assumptions are made in this
> prediction about spinnakers and whisker poles?  I race non-spinnaker and
> often on windward-leeward courses so we are often dead downwind and the
> whisker pole makes a huge difference going downwind wing on wing.  I am
> wondering if the polars take this into account.  Dave
>
> Aries
> 1990 C&C 34+
> New London, CT
>
>
> ___
>
> Thanks everyone for supporting this list with your contributions.  Each
> and every one is greatly appreciated.  If you want to support the list -
> use PayPal to send contribution --   https://www.paypal.me/stumurray
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>
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Stus-List downwind polars

[David Knecht via CnC-List]

The polars for my boat predict an optimal downwind speed at an angle around 
145° true.   Does anyone know what assumptions are made in this prediction 
about spinnakers and whisker poles?  I race non-spinnaker and often on 
windward-leeward courses so we are often dead downwind and the whisker pole 
makes a huge difference going downwind wing on wing.  I am wondering if the 
polars take this into account.  Dave

Aries
1990 C&C 34+
New London, CT



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