[Rhodes22-list] Centerboard and Sail Trim and Leeway
David Walker
david.walker5 at comcast.net
Fri Jul 31 14:45:17 EDT 2009
Yesterday I got the chance to sail in 5-10 kt wind and relatively flat
water. I set the boat up on a beam reach (apparent wind 90 degreees). The
course was was 060 M by my steering compass. We were able to do about
.5 - 4 kts SOG by the GPS.
With the board down our COG (Course over ground) was 055-057 M
With the board up out COG was 045-048 M
Although my steering compass is not compensated and thus has unknown
deviation, since it was held steady at 060 the deviation has no importance
here. Lowering the board reduced leeway by about 10 degrees. Lowering the
board had no observed effect on SOG although wind variation could have
hidden a small effect. Based on these results I see no reason to sail with
the board up unless in very thin water and one very good reason to sail with
it down.
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 3:13 PM
Subject: Re: [Rhodes22-list] Centerboard and Sail Trim
>
> David,
>
> By "relatively flat" I certainly agree. On close reaches so far I've
> found
> that it's easier for me to get in the groove with about a 10-15 degree
> heel,
> which I consider relatively flat. Anything over that and I most always
> slow
> down.
>
> Reference your statement that there is no reason (healing, light air,
> heavy air) to sail on the wind with the board up, does the term "sail on
> the
> wind" mean close-hauled or any close reach? With the Rhodes' keel it is
> obviously able to sail on a close reach without the centerboard down.
> Many
> times I've experimented with the board up and down and it always creates
> enough drag to reduce speed.
>
> I don't disagree with your statement, "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." However, that's all
> relative too. I typically sail with the board up on a close reach and
> balance the sails so there's no pressure on the tiller. See picture below
> (normally I do lock the tiller after balancing the sails). I am anxious
> to
> try the board down again. When moving around the boat to get and get rid
> of
> beer, stability is sometimes more important than speed.
>
> Lee
>
>
>
> David Walker-19 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.
>>>
>>> __________________________________________________
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>>>
>>
>>
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>>
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> At+Ease+in+March+012.jpg
> --
> View this message in context:
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