[Rhodes22-list] Centerboard and Sail Trim

Lou Rosenberg lsr3 at nyu.edu
Tue Jul 28 11:51:07 EDT 2009


Dave

Where can I buy Deck Apes?
they're not in the WM catalog?

Lou

On Jul 28, 2009, at 11:52 AM, David Walker wrote:

> I've tried to stay quiet while watching these posts fly by but I  
> have to
> make a few comments.
>
> 1)  The R22 sails basically like a big dinghy. It really wants to sail
> relatively flat.  This gives maximum depth to the CB, least wetted  
> surface
> and best hull form factor in the water.   All heel does is  
> effectively lower
> the sails, create weather helm and portentially pull the rudder out  
> of the
> water. If the rudder is partially out of the water due to heel, it  
> is less
> effective and requires more angle which creates drag and can stall the
> rudder.  Some (not all) keel boats can sail faster with significant  
> heeling
> because they are designed with significant hull overhangs which add
> waterline length whwn heeling.  This usually comes about due to  
> specific
> racing class design formulas.
>
> All that being said the ways to reduce heal are to a) use deck  
> apes, b) reef
> sails and c) trim sails to maximize lift and minimize drag
>
> 2)  All CB boats will sail better on the wind with the board down.   
> Water
> passing by the boards leading edge at the leeway angle creates lift  
> which
> keeps the boat going intoo the wind.  The lateral resistance of the  
> board is
> mimimal compared to the sails.  There is no reason (healing, light  
> air,
> heavy air) to sail on the wind with the board up.  The amount of  
> board down
> can be experimented with to modify weather/lee helm as the CE   
> (center of
> effort) of the board will change relative to the CE of the sails  
> has the
> board is lowered.  On a run, racing sailors will raise the board to  
> reduce
> drag, but you will find that makes steering more difficult as the  
> board and
> the rudder combine to create directional stability.
>
> For those interested I reccommend a small paper back book entitled  
> "Sail
> Trim - Theory and Practice" by Peter Hahne, published by Sheridan  
> House.  He
> describes in detail, trimming techniques to use to optimize sail  
> trim for
> all conditions.
>
>
> David Walker
>
> www.davidwalkerphotography.com
>
> Event Specialists
>
> 781-639-2707 Office
> 781-718-8690 Cell
> ----- Original Message -----
> From: "Leland" <LKUHN at cnmc.org>
> To: <rhodes22-list at rhodes22.org>
> Sent: Tuesday, July 28, 2009 10:07 AM
> Subject: Re: [Rhodes22-list] Partial Mainsail
>
>
>>
>> John,
>>
>> That makes sense.  If the boat normally heels less with the  
>> centerboard
>> up,
>> it stands to reason that it would also heel less in a big gust of  
>> wind.
>>
>> Lee
>>
>>
>>
>> jlock wrote:
>>>
>>> Actually I think it is the opposite.  With the board up, a gust will
>>> tend to push the hull sideways more easily and expend some energy
>>> doing so, producing less heel.  But with the board down, it will  
>>> offer
>>> resistance to the sideways push of the gust at a very low angle.   
>>> The
>>> results will be more heel above the waterline.
>>>
>>> Cheers!
>>> John Lock
>>> ~~~~~~~~~~~~~~~~~~
>>> s/v Pandion - '79 Rhodes 22
>>> Lake Sinclair, GA
>>> ~~~~~~~~~~~~~~~~~~
>>>
>>> On Jul 27, 2009, at 13:41, MichaelT wrote:
>>>> I'll have to balance the compromises here w/ needing to get
>>>> somewhere vs a
>>>> relaxing time.
>>>>
>>>> Btw, how real is the risk of a knockdown w/ the board up?
>>>> Has there been any reported knockdowns with the board up?
>>>> I suppose if a BIG gust came across and the board was up that the
>>>> boat will
>>>> react and heel much easier.
>>>>
>>>> Michael
>>>>
>>>>
>>>> Arthur H. Czerwonky wrote:
>>>>>
>>>>> Michael,
>>>>>
>>>>> These 'board up' options are a new one to me, partly because I  
>>>>> began
>>>>> serious sailing in a racing mode.  I do not know of anyone who
>>>>> would beat
>>>>> into the wind with the board up in competition, certainly due to
>>>>> slippage,
>>>>> which Hank emphasizes so well, but also the risk of knockdown.  I
>>>>> have
>>>>> never tried it, Michael, but I'd approach this technique with
>>>>> caution,
>>>>> especially if your wife is aboard.
>>>>>
>>>>> Happy sailing,
>>>>>
>>>>> Art
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>>> From: MichaelT <mticse at gmail.com>
>>>>>> Sent: Jul 27, 2009 9:56 AM
>>>>>> To: rhodes22-list at rhodes22.org
>>>>>> Subject: Re: [Rhodes22-list] Partial Mainsail
>>>>>>
>>>>>>
>>>>>> Thanks for the first hand knowledge wrt the centerboard.
>>>>>> You've certainly changed the fundamentals of my logic. Womehow my
>>>>>> flawed
>>>>>> thinking was that with the board up that the Rhodes would heel
>>>>>> more and
>>>>>> difficult to turn. On the contrary, the Rhodes actually sails
>>>>>> better (i.e.
>>>>>> less heel, easy to to turn) with the board up. Definitely
>>>>>> something I will
>>>>>> do this week.
>>>>>>
>>>>>> Thanks Lee!
>>>>>> Michael
>>>>>>
>>>>>>
>>>>>> Leland wrote:
>>>>>>>
>>>>>>> Michael,
>>>>>>>
>>>>>>> With the board down it will allow you to sail closer to the wind
>>>>>>> and
>>>>>>> make
>>>>>>> better headway (less drifting).
>>>>>>>
>>>>>>> However, the faster you go the less impact the board will  
>>>>>>> have on
>>>>>>> both
>>>>>>> sailing close to the wind and headway.  The board is most useful
>>>>>>> if you
>>>>>>> want to make headway in light wind.
>>>>>>>
>>>>>>> I'm a daysailor so the only time I need to make better  
>>>>>>> headway is
>>>>>>> if
>>>>>>> it's
>>>>>>> necessary to get back to my marina at the end of the day.  With
>>>>>>> yesterday's high wind and the current and chop pushing me away
>>>>>>> from the
>>>>>>> wind, I never once lowered my board and sailed part of the time
>>>>>>> on broad
>>>>>>> reaches and runs.  On tacks the boat turned like a sports car.
>>>>>>>
>>>>>>> With the board down it will act as a pivot point and allow  
>>>>>>> you to
>>>>>>> turn
>>>>>>> easier whether you are tacking or motoring around your slip.  I
>>>>>>> don't
>>>>>>> use
>>>>>>> if for either one.
>>>>>>>
>>>>>>> I've measured my speed countless times with the board up and  
>>>>>>> down
>>>>>>> and it
>>>>>>> has always had a negative impact on speed.  I think the term  
>>>>>>> is VMG
>>>>>>> (velocity made good?) which measures how much headway you're
>>>>>>> actually
>>>>>>> making.  If I could figure out how to measure it on my GPS I'm
>>>>>>> sure it
>>>>>>> would show that the board helps, but with the reduction in speed
>>>>>>> it sure
>>>>>>> doesn't seem that way.
>>>>>>>
>>>>>>> Lee
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> MichaelT wrote:
>>>>>>>>
>>>>>>>> Lee,
>>>>>>>>
>>>>>>>> I was just thinking about bringing the centerboard up as you
>>>>>>>> suggested,
>>>>>>>> but have concerns.
>>>>>>>> Did you flip bringing the centerboard up and down. Down when
>>>>>>>> tacking
>>>>>>>> and
>>>>>>>> up after the tack?
>>>>>>>> I remember when I forgot to let the centerboard down and all I
>>>>>>>> could
>>>>>>>> remember was going sideways and difficulty in making  
>>>>>>>> headway. In
>>>>>>>> essence
>>>>>>>> the boat was slipping and pushed sideways by the wind when the
>>>>>>>> centerboard is up. I suppose as long as we don't need to be
>>>>>>>> anywhere
>>>>>>>> soon
>>>>>>>> this is all fine.
>>>>>>>> At the end I'll have to let my wife judge!
>>>>>>>>
>>>>>>>> Great suggestion!
>>>>>>>> Michael
>>>>>>>>
>>>>>>>>
>>>>>>>> Leland wrote:
>>>>>>>>>
>>>>>>>>> Michael,
>>>>>>>>>
>>>>>>>>> You're getting lots of good advice.
>>>>>>>>>
>>>>>>>>> You'll have a little less heel with the board up.  From the
>>>>>>>>> Rhodes
>>>>>>>>> Owners' Site under FAQs under Rhodes vs. Com-Pac vs.
>>>>>>>>> Precisions:  5.
>>>>>>>>> Retract the centerboard part way in a big breeze. The board is
>>>>>>>>> intentionally modest in weight, and does not contribute
>>>>>>>>> significantly
>>>>>>>>> to
>>>>>>>>> stability up or down. Raising the board part way will reduce
>>>>>>>>> both heel
>>>>>>>>> and weather helm.
>>>>>>>>>
>>>>>>>>> The quote refers to Precisions.  If I raise the board all the
>>>>>>>>> way on
>>>>>>>>> my
>>>>>>>>> Rhodes it usually only reduces heel by about 3 degrees but  
>>>>>>>>> your
>>>>>>>>> wife
>>>>>>>>> may
>>>>>>>>> appreciate it.
>>>>>>>>>
>>>>>>>>> In an 8-10 knot wind, lowering the boom will reduce heel also.
>>>>>>>>>
>>>>>>>>> As Dave mentioned the boat sails better with two sails.   
>>>>>>>>> For the
>>>>>>>>> amount
>>>>>>>>> of wind you described you probably weren't going fast  
>>>>>>>>> enough to
>>>>>>>>> tack.
>>>>>>>>> Come off the wind enough to get up some speed and you'll then
>>>>>>>>> be able
>>>>>>>>> to
>>>>>>>>> turn her sharply into the wind.
>>>>>>>>>
>>>>>>>>> When I first got my Rhodes I typically had too much sail out.
>>>>>>>>> You
>>>>>>>>> were
>>>>>>>>> wise to be conservative in your sail plan, but without any
>>>>>>>>> headsail
>>>>>>>>> and
>>>>>>>>> so little main you probably couldn't get enough speed to tack
>>>>>>>>> even if
>>>>>>>>> you had come off the wind.  Last week I was in a 12 knot wind.
>>>>>>>>> On a
>>>>>>>>> close reach with balanced sails with the board up and my 190
>>>>>>>>> lbs of
>>>>>>>>> rail
>>>>>>>>> meat, I had less than 20 degrees of heel with the boom up and
>>>>>>>>> the main
>>>>>>>>> reefed to 80%.  With the boom down I had the same heel with
>>>>>>>>> 100% main.
>>>>>>>>> I have my mainsail furling line marked for reefs at 60% and
>>>>>>>>> 80%.  If I
>>>>>>>>> have to reef the tiny little main beyond 60%, it's too windy
>>>>>>>>> for me
>>>>>>>>> (over 20 knots) and I go home.
>>>>>>>>>
>>>>>>>>> Good luck!
>>>>>>>>>
>>>>>>>>> Lee
>>>>>>>>> 1986 Rhodes22  At Ease
>>>>>>>>> Kent Island, MD
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> david.walker5 wrote:
>>>>>>>>>>
>>>>>>>>>> Stephen,
>>>>>>>>>>
>>>>>>>>>> Tacking with the jib, especially very light or heavy wind  
>>>>>>>>>> can be
>>>>>>>>>> challenging
>>>>>>>>>> too.  The problem is the jib is very powerfull and it  
>>>>>>>>>> wants to
>>>>>>>>>> push
>>>>>>>>>> the
>>>>>>>>>> boat
>>>>>>>>>> away from the tack.  One technique that has worked for me is
>>>>>>>>>> something
>>>>>>>>>> I
>>>>>>>>>> borrowed from sailing a square rigger.  When you push the
>>>>>>>>>> tiller to
>>>>>>>>>> lee,
>>>>>>>>>> loosen the jibe immediately, but do not let the sheet fly. 
>>>>>>>>>> (for
>>>>>>>>>> those
>>>>>>>>>> interested its called scandalizing the jib)  This reduces the
>>>>>>>>>> drive
>>>>>>>>>> of
>>>>>>>>>> the
>>>>>>>>>> sail and allows it to turn up wind.  Just as the bow comes
>>>>>>>>>> into the
>>>>>>>>>> wind,
>>>>>>>>>> tighten the sheet a little. The wind will then backwind the
>>>>>>>>>> jib and
>>>>>>>>>> push the
>>>>>>>>>> bow the rest of the way onto the new tack. As you come  
>>>>>>>>>> through
>>>>>>>>>> the
>>>>>>>>>> wind, the
>>>>>>>>>> wind on the new tack will push the sail across to the new
>>>>>>>>>> tack.  In
>>>>>>>>>> really
>>>>>>>>>> heavy wind you may end up "in stays" or headed into the  
>>>>>>>>>> wind and
>>>>>>>>>> start
>>>>>>>>>> to be
>>>>>>>>>> pushed backwards.  In that case as I said in an earlier post,
>>>>>>>>>> shift
>>>>>>>>>> the
>>>>>>>>>> rudder (tiller to windward) and the boat will back onto the
>>>>>>>>>> new tack
>>>>>>>>>> and
>>>>>>>>>> start to sail.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> David Walker
>>>>>>>>>>
>>>>>>>>>> www.davidwalkerphotography.com
>>>>>>>>>>
>>>>>>>>>> Event Specialists
>>>>>>>>>>
>>>>>>>>>> 781-639-2707 Office
>>>>>>>>>> 781-718-8690 Cell
>>>>>>>>>> ----- Original Message -----
>>>>>>>>>> From: "Stephen Staum" <staum at earthlink.net>
>>>>>>>>>> To: "The Rhodes 22 Email List" <rhodes22-list at rhodes22.org>
>>>>>>>>>> Sent: Friday, July 24, 2009 3:32 PM
>>>>>>>>>> Subject: Re: [Rhodes22-list] Partial Mainsail
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>> Michael,
>>>>>>>>>>> I too have a wife who likes to sail flat. I have an '87 w a
>>>>>>>>>>> 184 per
>>>>>>>>>>> cent genoa. I usually start w 1/2 of the genny as the jib
>>>>>>>>>>> really
>>>>>>>>>>> powers this boat. Even w the full main out (alone) u will
>>>>>>>>>>> struggle
>>>>>>>>>>> to
>>>>>>>>>>> come about. Also, if u have the full jib out in light winds,
>>>>>>>>>>> it can
>>>>>>>>>>> be
>>>>>>>>>>> very difficult 2 get the jib 2 come across when coming  
>>>>>>>>>>> about.
>>>>>>>>>>> It is
>>>>>>>>>>> often easier 2 jibe or roll up 1/2 the jib b4 come about is
>>>>>>>>>>> started.
>>>>>>>>>>> Enjoy!
>>>>>>>>>>> Stephen Staum
>>>>>>>>>>> Sent from my iPhone
>>>>>>>>>>>
>>>>>>>>>>> On Jul 24, 2009, at 12:47 PM, MichaelT <mticse at gmail.com>
>>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Went out with the family on Sunday and wanted to play it  
>>>>>>>>>>>> safe.
>>>>>>>>>>>> Drew the IMF mainsail approx halfway on the boom (the  
>>>>>>>>>>>> letter
>>>>>>>>>>>> R on
>>>>>>>>>>>> the sail
>>>>>>>>>>>> wasn't showing).
>>>>>>>>>>>> Wanted to keep things simple and used no jib. Centerboard
>>>>>>>>>>>> was down
>>>>>>>>>>>> all the
>>>>>>>>>>>> way.
>>>>>>>>>>>> The boat stayed flat as a pancake which was the desired
>>>>>>>>>>>> effect.
>>>>>>>>>>>> My wife wants no heeling whatsoever. Problem I had was I
>>>>>>>>>>>> couldn't
>>>>>>>>>>>> tack.
>>>>>>>>>>>> It even had a hard time getting into irons and just  
>>>>>>>>>>>> couldn't
>>>>>>>>>>>> cutover.
>>>>>>>>>>>> The only way I could change direction was to spin 2/3's
>>>>>>>>>>>> around in a
>>>>>>>>>>>> jibe.
>>>>>>>>>>>> I didn't want to experiment and let out more sail so we  
>>>>>>>>>>>> just
>>>>>>>>>>>> enjoyed
>>>>>>>>>>>> sailing
>>>>>>>>>>>> the next hour like this.
>>>>>>>>>>>> Is this normal behaviour? What am I doing wrong?
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks,
>>>>>>>>>>>> Michael
>>>>>>>>>>>> -- 
>>>>>>>>>>>> View this message in context:
>>>>>>>>>>>> http://www.nabble.com/Partial-Mainsail-
>>>>>>>>>>>> tp24647946p24647946.html
>>>>>>>>>>>> Sent from the Rhodes 22 mailing list archive at Nabble.com.
>>>>>>>>>>>>
>>>>>>>>>>>> __________________________________________________
>>>>>>>>>>>> To subscribe/unsubscribe or for help with using the mailing
>>>>>>>>>>>> list go
>>>>>>>>>>>> to http://www.rhodes22.org/list
>>>>>>>>>>>> __________________________________________________
>>>>>>>>>>> __________________________________________________
>>>>>>>>>>> To subscribe/unsubscribe or for help with using the mailing
>>>>>>>>>>> list go
>>>>>>>>>>> to
>>>>>>>>>>> http://www.rhodes22.org/list
>>>>>>>>>>> __________________________________________________
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> __________________________________________________
>>>>>>>>>> To subscribe/unsubscribe or for help with using the mailing
>>>>>>>>>> list go
>>>>>>>>>> to
>>>>>>>>>> http://www.rhodes22.org/list
>>>>>>>>>> __________________________________________________
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> -- 
>>>>>> View this message in context:
>>>> http://www.nabble.com/Partial-Mainsail-tp24647946p24681160.html
>>>>>> Sent from the Rhodes 22 mailing list archive at Nabble.com.
>>>>>>
>>>>>> __________________________________________________
>>>>>> To subscribe/unsubscribe or for help with using the mailing list
>>>>>> go to
>>>> http://www.rhodes22.org/list
>>>>>> __________________________________________________
>>>>>
>>>>> __________________________________________________
>>>>> To subscribe/unsubscribe or for help with using the mailing  
>>>>> list go
>>>>> to
>>>>> http://www.rhodes22.org/list
>>>>> __________________________________________________
>>>>>
>>>>>
>>>>
>>>> -- 
>>>> View this message in context:
>>>> http://www.nabble.com/Partial-Mainsail-tp24647946p24685194.html
>>>> Sent from the Rhodes 22 mailing list archive at Nabble.com.
>>>>
>>>> __________________________________________________
>>>> To subscribe/unsubscribe or for help with using the mailing list go
>>>> to http://www.rhodes22.org/list
>>>> __________________________________________________
>>>>
>>>
>>> __________________________________________________
>>> To subscribe/unsubscribe or for help with using the mailing list  
>>> go to
>>> http://www.rhodes22.org/list
>>> __________________________________________________
>>>
>>>
>>
>> -- 
>> View this message in context:
>> http://www.nabble.com/Partial-Mainsail-tp24647946p24698152.html
>> Sent from the Rhodes 22 mailing list archive at Nabble.com.
>>
>> __________________________________________________
>> To subscribe/unsubscribe or for help with using the mailing list  
>> go to
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>>
>
>
> __________________________________________________
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> to http://www.rhodes22.org/list
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Lou Rosenberg
Videographer

Steinhardt School of Culture, Education and
Human Development at NYU

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