[frers-list]Fairing keel and rudder
ARTHUR KELLEY
frers-list@lists.frers33.com
Mon, 09 Dec 2013 22:36:44 -0500 (EST)
Here's where we are so far. =C2=A0We have information from 3 boats. =C2=A0I=
t would=20
be useful to get more.
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0Boat A =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 Boat B =C2=A0 =C2=A0=
=20
=C2=A0 =C2=A0 =C2=A0 =C2=A0Boat C=09=09
Rudder Length =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A060.5=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 60=
=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=20
60=E2=80=9D
Rudder Width from skeg =C2=A0 =C2=A0=C2=A028.5=E2=80=9D =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 26=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 28.5=E2=80=9D
=C2=A0 =C2=A0 =C2=A0parallel to top of rudder=C2=A0=C2=A0
Rudder edge =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 3/16=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 ~1/2" =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=20
=C2=A01/8"
Keel depth =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 54.5=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 55=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=20
=C2=A0 =C2=A0 55.5=E2=80=9D
Keel Root =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A068.5=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0=
=C2=A0 =C2=A0 =C2=A0 68.5=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=20
=C2=A0 =C2=A0 69=E2=80=9D
Keel Foot =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 not measured =C2=A0 =C2=A0=
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=20
=C2=A028=E2=80=9D
Keel edge =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A03/16=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0=
=C2=A0 =C2=A0 =C2=A01/8=E2=80=9D =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=
=20
=C2=A0 =C2=A0 1/8=E2=80=9D
It appears that all three of these boats have nearly identically sized=20
keels although it would be interesting to see if the curvature of the=20
trailing edge matches. =C2=A0We should probably at least get a measurement=
=20
horizontally at a station halfway between the root and the foot. =C2=A0It's=
=20
still difficult to tell in a second round of photos.=C2=A0=C2=A0The differe=
nce=20
between the keel depths is probably not important, and probably not=20
intentional. =C2=A0Boat A has relatively soft fairing compound on the botto=
m=20
of the keel which appears to have been crushed when set aground for the=20
winter.
On these three boats, it appears two have had their rudder trailing=20
edges "faired" to a finer than original edge by adding an extension of=20
approximately 2.5". =C2=A0
I will continue to gather measurements from whomever is willing to=20
provide them so we can see how close the boats' foils still are. =C2=A0With=
=20
owner's permissions perhaps we can then disclose which boat is which and=20
postulate whether any of this really makes a difference.
Art
On Mon, Dec 09, 2013 at 11:13 AM, Courtney Thomas wrote:
> On 12/7/2013 4:51 PM, ARTHUR KELLEY wrote:
>> I made an unplanned stop at the boatyard today to check my cover and=20
>> remembered this thread. Since we have two boats in the same yard, I=20
>> figured I'd check. Again, this was unplanned, so I was alone and did=20
>> not have a ruler or tape measure but used a sail tie to compare the=20
>> foils, and came back and measured the sail tie. Trends good,=20
>> accuracy, not so much.
>>
>> The keels seem pretty similar, both faired to about 1/8" (Boat A) or=20
>> a bit less on Boat B and both keels approximately the same length=20
>> (depth) below the bottom.
>>
>> The rudders were a completely different story. Boat B appears=20
>> "stock" with a fairly thick, rounded trailing edge. There is a=20
>> school of thought that suggests that the rounder edge reduces=20
>> turbulence when turning or when the rudder is offset from centerline=20
>> like when going upwind with some weather helm. Then again the=20
>> thicker edge does create more turbulence when running straight with=20
>> the rudder on centerline.
>>
>> The rudder on the Boat A had been faired to about 1/8", the same as=20
>> the keel, but to achieve this the trailing edge had been extended by=20
>> about 2 1/4" to 2 1/2". This also affected the roundness of the=20
>> bottom of the rudder. Both rudders seem to be the same length.=20
>> Measuring from the leading edge of the rudder just below where the=20
>> notch for the skeg ends, and running parallel to the top edge of the=20
>> rudder (see attachment), Boat A's rudder measured approximately 28=20
>> 1/2" and Boat B approximately 26 1/4". Remember I am measuring to=20
>> knots in a sail tie here! Both were about 60" long, top to bottom.
>>
>> I photographed both rudders, traced them in the computer, then=20
>> overlaid the profiles. The diagram (attached) is perhaps not as=20
>> smooth and clean as they could be but this should be sufficient to=20
>> get the general concept - and generate discussion. I would need to=20
>> re-photograph the keels, the perspective was different and the=20
>> overlay just did not work.
>>
>> I have not spoken to the other owner yet about what he knows about=20
>> any modifications to his foil(s), so am keeping the identities of the=20
>> boat anonymous for now. He frequently beats me, but I don't think=20
>> that's raw boat speed as much as he and his crew just being a bit=20
>> better than we are.
>>
>> Joyce, if you come up with your diagrams I'd be happy to post them on=20
>> the class site, perhaps in the FAQ section.
>>
>> If anyone else wants to photograph their rudder or keel I can try to=20
>> add those to the comparison. The photo would have to be taken with=20
>> the camera aligned approximately mid-point on the foil and=20
>> perpendicular to it.
>>
>> These specifications probably should have been more closely regulated=20
>> in the early days of the class, but for now perhaps we should=20
>> understand what the fleet looks like and try to avoid too much=20
>> further deviation. In my mind changing the location of lead would be=20
>> against the one-design rules so Bill, I applaud you for planning=20
>> ahead for the event that someone wants to bring the boat back into=20
>> class specs.
>>
>> Regards,
>> Art
>>
>> On Thu, Nov 28, 2013 at 09:25 AM, Scott Marino wrote:
>>
>>> Joyce,
>>> Sounds like those pics might be a nice additions to the Frers=20
>>> website for all to see.
>>> Scott
>>>
>>> --------------------------------------------
>>> On Wed, 11/27/13, Joyce Oberdorf wrote:
>>>
>>> Subject: Re: [frers-list]Fairing keel and rudder
>>> To: frers-list@lists.frers33.com
>>> Date: Wednesday, November 27, 2013, 12:48 PM
>>> Bill--
>>> Here is what I know. When I bought Checkmate,
>>> eons ago, we looked at 4
>>> Frers 33s Each one had a slightly different keel and rudder.
>>> Wolverine had a
>>> less deep keel-- but NOT the "shallow keel" version.
>>> Impetuous had a deeper
>>> keel, faired to a fine blade, as was the rudder.
>>> We measured with calipers the thickness of the trailing
>>> edges. ALL
>>> DIFFERENT>
>>> This is apparently not covered by class rules. At that
>>> time (way back in
>>> the 90s), Impetuous was one of the leading boats, and the
>>> owner, Paul
>>> Zabetakis, was class president at the time. And close by. So
>>> we decided to
>>> go with that. We extended the rudder about 3 includes
>>> to fair it from about
>>> 3/4 inch to a fine edge. Did the same to keel. We didn't
>>> have templates. If
>>> I can find the diagram of the two boats we measured (I
>>> plotted the shapes on
>>> graph paper, I'll copy scan and email.
>>> Joyce
>>> On 11/18/13 1:44 PM, "Bill Thompson" wrote:
>>>
>>>> Hi all,
>>>>
>>>> Have sanded d'Ad lib's hull - waterline and below -
>>> back to the vinyl ester.
>>>> Brutal work. The good news is, after 27 years, not a
>>> single blister, soft spot
>>>> or other imperfection. Washed and wetted down there is
>>> no ripple of
>>>> imperfection to be found in the reflection. Come
>>> spring, sealant and 6 coats
>>>> of inter protect before bottom paint should keep her
>>> dry and healthy for a
>>>> good long time. Pics avail. if anyone would like to
>>> see.
>>>>
>>>> However, keel and rudder (which is still dry) are not
>>> as fair, so I'm
>>>> wondering if anyone has templates and/or methodology to
>>> suggest, so I can
>>>> bring them fair, prior to coating and finishing. All
>>> help appreciated.
>>>>
>>>> Bill Thompson
>>>> Montreal
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> Art,
>
> Sure would appreciate the specs on the keels. I was told on purchase=20
> that mine had been modified by a previous owner but now am not so=20
> sure. My main concern is regarding the keel depth and it's effect on=20
> boat performance.
>
> All thoughts and experience appreciated,
>
> Courtney
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