Filippi carbon fin
ncmo...@yahoo.co.uk
Whilst perusing the Filippi website I came across this page:
http://www.filippiboats.it/derive_eng.htm
which shows a carbon fin.
I was just wondering if anyone has tried one, and if they have any
comments?
Thanks,
Nick M
J Flory
My friend made some that I have been using on my Empacher 1x for the
past couple of seasons.
Advantage: They don't bend like the aluminum ones do.
Disadvantage: They must be laid up carefully to avoid any lateral
curve. There's no way to bend them straight if they have a slight hook.
chris harrison
> Whilst perusing the Filippi website I came across this page:
> http://www.filippiboats.it/derive_eng.htm
> which shows a carbon fin.
'Interesting' photoshopping in the banner of that page!
KC
Heh... yeah, really! One has to wonder at that, "why?"
-K
Carl Douglas
There's a strong smell of bullshit in:
1. "Our Research Centre"
2. "sought to optimise the old NACA aerodynamic profiles"
That spiel, which may have suffered in the translation, also betrays a
misunderstanding of the true function of a 1x fin, which is to generate
modest amounts of lift at small angles of attack in order to prevent
incipient yaw, but to stall promptly when you do need to make a
significant course correction. A foil-section fin - & I should perhaps
note that the "old NACA profiles" are time-honoured, are still most
widely used & are most unlikely to have been improved upon in this case,
will generate lots of lift in direct proportion to, & over a wide range
of, angle of attack, so it will fight you when you do want to make a
course change.
Cheers -
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing low-drag Riggers/Advanced Accessories
Write: The Boathouse, Timsway, Chertsey Lane, Staines TW18 3JY, UK
Email: ca...@carldouglas.co.uk Tel: +44(0)1784-456344 Fax: -466550
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)
vet...@hotmail.com
> 'Interesting' photoshopping in the banner of that page!
Interesting translations elsewhere on the site (? babelfish)
"the application is more complex, considering the most exasperate
solicitations a sweep boat is subjected to"
I never get any solicitations (exasperate or otherwise) in my sculling
boat - perhaps I should return to rowing
Paul W
simonk
news:1146070269.6...@u72g2000cwu.googlegroups.com...
> chris harrison wrote:
>> 'Interesting' photoshopping in the banner of that page!
>
> Interesting translations elsewhere on the site (? babelfish)
I work with a large number of Italians, and their written English, while
generally excellent, does seem to have a number of quaint turns of phrase.
It's not quite "engrish", but it often raises a smile.
> "the application is more complex, considering the most exasperate
> solicitations a sweep boat is subjected to"
I came across this yesterday:
http://www.uk.vespa.com/_vti_g2_prod.asp?brand=VESPA&country=GB&language=EN
"Prices - all the opportunities to click immediately"
"Park in the Virtual Garage your configurated scooter"
bill
Yeah, the translation from Italian to English makes a Campagnolo page
look like it was written by Daniel Webster himself!
bill
Carl Douglas wrote:
> ncmo...@yahoo.co.uk wrote:
> > Hi,
> >
> > Whilst perusing the Filippi website I came across this page:
> > http://www.filippiboats.it/derive_eng.htm
> > which shows a carbon fin.
> >
> > I was just wondering if anyone has tried one, and if they have any
> > comments?
> >
> > Thanks,
> > Nick M
> >
>
> There's a strong smell of bullshit in:
> 1. "Our Research Centre"
> 2. "sought to optimise the old NACA aerodynamic profiles"
>
> That spiel, which may have suffered in the translation, also betrays a
> misunderstanding of the true function of a 1x fin, which is to generate
> modest amounts of lift at small angles of attack in order to prevent
> incipient yaw, but to stall promptly when you do need to make a
> significant course correction. A foil-section fin - & I should perhaps
> note that the "old NACA profiles" are time-honoured, are still most
> widely used & are most unlikely to have been improved upon in this case,
> will generate lots of lift in direct proportion to, & over a wide range
> of, angle of attack, so it will fight you when you do want to make a
> course change.
I agree with the stench, but I am not so sure I see anything inherently
bad about using a section with a higher stall angle--provided one is
not paying dearly in terms of straight ahead drag. Of course this is
really what we are after--good non-stalling performance over some small
anlge of attack, with the least resistance possible, and so any section
that could hope to have a significantly large stall angle is apt to be
quite poor. Thicker foils have higher drag in staight ahead or small
angle of attack, and so would be a bad choice. From my own design and
boating experience, I'd say I wouldn't see any advantage going higher
than a 6% t/c ratio (NACA 006 or laminar 66-006). Because the fin
needs some stiffness, you have to have some sort of thickness and so a
true "flat plate" does not have any advantage--unless you make it out
of steel or even tungsten! But for the purpose, I wonder how much
difference one would really notice between, say, a 0003 shape, as
opposed to a radiused leading edge, feathered trailing edge with 3%
thickness.
Some would try to say, "by choosing a fancy Goettingen such & such
section, we make the area only 1/2 what would be required with a flat
plate and so our total resistance is still lower." Well, you really
have to compare the slope of the lift curves in absolute lift per
degree, and with it the induced drag, to make a proper comparison. CL
is close to linear at small angles, the CL being applied to the area,
the slope determined by aspect ratio, and so, keeping the aspect ratios
the same, the flat plate will generate the same turning force at a
smaller yaw angle, and so the course-keeping hysteresis will be less
with teh flat plate....
And so in the end, I think I agree with Carl, but with a different
aroma.
KC
Carl Douglas wrote:
> ncmo...@yahoo.co.uk wrote:
> > Hi,
> >
> > Whilst perusing the Filippi website I came across this page:
> > http://www.filippiboats.it/derive_eng.htm
> > which shows a carbon fin.
> >
> > I was just wondering if anyone has tried one, and if they have any
> > comments?
> >
> > Thanks,
> > Nick M
> >
>
> note that the "old NACA profiles" are time-honoured, are still most
> widely used & are most unlikely to have been improved upon in this case,
I doubt they meant they improved upon the foil section geometry, but
rather took a certain NACA foil, and optimized the plan-view area and
shape (which does look different from most fins I've seen), keeping the
NACA foil profile (cross section). Whether they were successful in
this "optimization" is another question, however.
As for the usefulness (or not) of a large stall angle foil for a 1x
fin... I've not thought of it before in a design sense (since I'm not a
boat designer). However, apart from the increased drag associated with
a large stall angle foil, if what you want is to go straight in
flat/calm water, why *wouldn't* you want a large stall angle for a
racing boat? It's only going to help correct steering mistakes for
you, no? I can see that for training you might not want it (having to
make river turns would be a bear). But for a straight, bouyed 2km
course... seems like it would be a nice feature.
Maybe one could have swappable fins! :-) Like tires for cyclists: one
fin for training, another for racing. Nah, just buy two boats. ;^)
-Kieran
bill
Actually, if you were to want to make efficient rapid turns at speed,
you would not want stall. Stall has associated with it a high drag,
and not as much lift as pre-stall. The point is that you don't ever
need to do such a thing in a shell, and furthermore, that the starting
circulation around the long slender shell hull is so large that you
cannot ever muscle the shell into a high angle of attack anyway, and so
the point of "high stall angle" or "delayed stall angle" foils if of no
use and will increase straight-ahead drag due to their inherent higher
drag (thicker sections therefore larger viscous wake).
For those times when you are trying to make big angle changes you are
typically not moving ahead-- you are having to backwater, and are not
moving forward, and so the fin is inconsequential in these
cirumstances...:-)
nc...@hotmail.com
They seem to be quite common on empachers and fillipis now. I've
not actually used one but I've heard they are good, except if you are
rowing somewhere with weed in the water - then the thing to do is find
a shallow bit and clip the bottom so that the aluminums carrier bends
and the fin is angled backwards. It worked on an empacher double
anyway, the fillippi without this 'modification' they were doing pieces
against, had many more problems with weed.
Nick
KC
n...@hotmail.com wrote:
>
> the fillippi without this 'modification' they were doing pieces
> against, had many more problems with weed.
I always recommend laying off the weed if you're going to go for a
row...
-KC ;-)
Rob
UTRC some of you over there may know him). I liked his response and
asked him if I could post it. He said yes and *with* attribution:
I read this discourse and I think of Macbeth, "...full of sound and
fury,
signifying nothing..." Are we really supposed to believe that fin
design
should take into consideration the hydrodynamic lift and drag of a foil
that
is - in most cases - lost in a swirl of disturbed flow at the stern of
a
shell and whose angle of attack is on average zero? I don't think so.
Neither does Empacher maker of fast boats with flat plates of aluminum
as
fins.
More credible is fin design that minimizes frontal section and
therefore
drag at angles of attack + or - 5 or so degrees. Some form of
symmetrical
air foil will do that. I assume that beyond 5+ degrees all fins stall
and
therefore create lots of drag.
Perhaps a more interesting discussion is where to locate the fin fore
and
aft. For those who ply the waters in King's, we are pleased with the
boats
tracking ability in buoyed lanes and on serpentine head courses. And
this
because the fin is fairly far forward, just aft of the cockpit. This
is in
contrast to those who row the yellow boats with their fins placed well
aft
and who sometimes complain about the difficulty of turning their
shells.
Interestingly, I have a few friends who have resorted to cutting down
their
Empacher fins or like the Dutch have had Empacher make them smaller so
that
they can race their boats on the twisty Amstel.
>From these observations, I conclude that fins should have a relatively
fine
hydrodynamic shape to minimize frontal drag and they should be placed
closer
to the center of lateral resistance so that the boat will track on a
straight course but with subtle pressure respond to the oarsman's
desire to
turn.
Soliloquy finished this poor player having strutted and fretted his
hour
upon the stage will be heard no more.
FYI another rower I sent the earlier post to pointed out: Macbeth was
a Scotsman not a Finn.
J Flory
Rob wrote:
> I forwarded some of the minutiae to my good friend Charlie Hamlin (ex
> UTRC some of you over there may know him). I liked his response and
> asked him if I could post it. He said yes and *with* attribution:
> I read this discourse and I think of Macbeth, "...full of sound and
> fury, signifying nothing..." Are we really supposed to believe that fin
> design should take into consideration the hydrodynamic lift and drag of a foil
> that is - in most cases - lost in a swirl of disturbed flow at the stern of
> a shell and whose angle of attack is on average zero? I don't think so.
> Neither does Empacher maker of fast boats with flat plates of aluminum
> as fins.
>
> More credible is fin design that minimizes frontal section and
> therefore drag at angles of attack + or - 5 or so degrees. Some form of
> symmetrical air foil will do that. I assume that beyond 5+ degrees all fins stall
> and therefore create lots of drag.
I should have mentioned that the carbon fiber fins we have been working
with have only slight foil-ish cross-section; they're more or less
flat.
> Perhaps a more interesting discussion is where to locate the fin fore
> and aft. For those who ply the waters in King's, we are pleased with the
> boats tracking ability in buoyed lanes and on serpentine head courses. And
> this because the fin is fairly far forward, just aft of the cockpit. This
> is in contrast to those who row the yellow boats with their fins placed well aft
> and who sometimes complain about the difficulty of turning their shells.
This is amusing because I (in a yellow boat) bumped into Charlie (in
his King?) at the 180 degree stake turn in the Green Mountain Head last
fall. He had just apssed me and turned his King far faster than I
could get my E-boat turned. No damage thank goodness (and the bump
actually helped both of us turn) but this underscores the difference.
> Interestingly, I have a few friends who have resorted to cutting down
> their Empacher fins or like the Dutch have had Empacher make them smaller so
> that they can race their boats on the twisty Amstel.
The latest iteration of our carbon fiber Empacher skeg is much smaller
in lateral view than the stock metal one. It helps but does not
entirely solve the Empacher's unwillingness to turn. We attribute this
to: (1) the hull shape, more rocker especially in the bow might help,
and (2) skeg location (in agreement with Charlies & Rob's view).
The rake of the front edge is similar to that of the stock skeg so
weed-catching is not a problem.
> From these observations, I conclude that fins should have a relatively
> fine hydrodynamic shape to minimize frontal drag and they should be placed
> closer to the center of lateral resistance so that the boat will track on a
> straight course but with subtle pressure respond to the oarsman's
> desire to turn.
Essentially there are two sets of requirements depending on the type of
racing one is doing. Many of us over here race on twisty courses (e.g.
the Charles or Fish) or do stake races like Green Mountain Head or
Silver Skiff where turnability is at a premium. For 2k or 1k
reluctance to turn can be an advantage.
Empacher, Filippi, and apparently now Hudson have drop-in skegs secured
by screws so they are easy to switch. Some people over here DO use
different sized skegs for different types of courses.
Carl Douglas
> I forwarded some of the minutiae to my good friend Charlie Hamlin (ex
> UTRC some of you over there may know him). I liked his response and
> asked him if I could post it. He said yes and *with* attribution:
>
> I read this discourse and I think of Macbeth, "...full of sound and
> fury,
> signifying nothing..." Are we really supposed to believe that fin
> design
> should take into consideration the hydrodynamic lift and drag of a foil
>
> that
> is - in most cases - lost in a swirl of disturbed flow at the stern of
> a
> shell and whose angle of attack is on average zero? I don't think so.
What?
1. A fin that does not generate lift when inclined to the flow
direction, despite being beneath the boat, does nothing except produce
drag. You can do that with a plain vertical rod, but why would you wish to?
2. The typical tin plate rudder on most shells is even smaller than the
fin &, due to its short major chord suffers worse still from being in
the most disturbed flow of the turbulent boundary layer. Yet, though
they work badly, they do work after a fashion, & that fashion does note
exclude a component of lift.
So I think bending his thinking around Shakespeare's fine words got the
better of your correspondent.
> Neither does Empacher maker of fast boats with flat plates of aluminum
> as
> fins.
But, yes, flat fins do work fine on singles.
>
> More credible is fin design that minimizes frontal section and
> therefore
> drag at angles of attack + or - 5 or so degrees. Some form of
> symmetrical
> air foil will do that. I assume that beyond 5+ degrees all fins stall
> and
> therefore create lots of drag.
Drag on a fin is a function of both frontal area & wetted surface. A
flat plate fin has very small frontal area (unless twisted, which should
not happen with even a modest hard-aluminium plate fin!)
A NACA-10 or -8 section fin is very fat & will probably not stall until
around 10 degrees AOA, by which point it will be generating loads of lift.
Your correspondent is probably familiar with the "drag bucket" concept,
which describes the shape of the plot of drag vs AOA, in which drag
mounts nonlinearly & rapidly with increasing AOA. Drag then jumps
further upon the onset of stall, but not all lift is lost even then.
>
> Perhaps a more interesting discussion is where to locate the fin fore
> and
> aft. For those who ply the waters in King's, we are pleased with the
> boats
> tracking ability in buoyed lanes and on serpentine head courses. And
> this
> because the fin is fairly far forward, just aft of the cockpit. This
> is in
> contrast to those who row the yellow boats with their fins placed well
> aft
> and who sometimes complain about the difficulty of turning their
> shells.
I agree that some fins are too far astern: if the bow is being blown off
course, they make keeping straight a tougher task.
>
> Interestingly, I have a few friends who have resorted to cutting down
> their
> Empacher fins or like the Dutch have had Empacher make them smaller so
> that
> they can race their boats on the twisty Amstel.
>
>>From these observations, I conclude that fins should have a relatively
> fine
> hydrodynamic shape to minimize frontal drag and they should be placed
> closer
> to the center of lateral resistance so that the boat will track on a
> straight course but with subtle pressure respond to the oarsman's
> desire to
> turn.
I follow your arguments but not your reasoning. What, in your view, is
the job of the fin? And what is the difference in straight-line drag
between 2 fins of equal size & profile, one being flat & 2mm thick (with
radiused leading & tapered trailing edges, the other an NACA-10 fin of
6mm thickness? Rather in favour of the flat plate.
>
> Soliloquy finished this poor player having strutted and fretted his
> hour
> upon the stage will be heard no more.
>
>
> FYI another rower I sent the earlier post to pointed out: Macbeth was
> a Scotsman not a Finn.
But all the Finns I know are Irishmen.
d...@topowest.com
>
> I always recommend laying off the weed if you're going to go for a
> row...
Fortunately, you can't forget the oars for long.
dl
ncmo...@yahoo.co.uk
>I can see that for training you might not want it (having to
>make river turns would be a bear). But for a straight, bouyed 2km
>course... seems like it would be a nice feature.
>Maybe one could have swappable fins! :-) Like tires for cyclists: one
>fin for training, another for racing. Nah, just buy two boats. ;^)
This agrees with the reply I had from UK Filippi - essentially, they
are apparently great on straight 2k courses, but are long (so easier to
accidentally remove on the bottom) and do catch the weed due to the
almost vertical front edge.
Interestingly this was the exact opposite of what I had thought from
reading the original website ("The trouble is when conditions change
from the ideal and other factors like lesser technical skill , cross
wind or effects of the stream come in to play. In these cases the boat
does not go perfectly straight and the fin acts as a brake by meeting
the flow of water at a less than optimal position.
") which seemed to my non-engineer mind to be suggesting that the
carbon fin would help you go round corners better!
Apparently some people do swap from the carbon version to a normal
aluminium fin depending on where they are rowing (they carbon fin fits
into the normal Filippi fin box).
They are also expensive! (GBP 75 + tax)
Cheers,
Nick
RMTT
> Maybe one could have swappable fins! :-) Like tires for cyclists: one
> fin for training, another for racing. Nah, just buy two boats. ;^)
>
> -Kieran
>
When racing on the Amstel River in eights, we do swap fins - the river fins
being much smaller in area, and less deep, than '2k' fins.
Rutger
Adriaan
And/or a larger rudder.
I was surprised to still see some (Nereus) eights equipped with "Amstel
rudder" (but with racing fin) on the first 2k regatta on the Bosbaan
last weekend.
--
Adriaan
KC
ncmo...@yahoo.co.uk wrote:
> Interestingly this was the exact opposite of what I had thought from
> reading the original website ("The trouble is when conditions change
> from the ideal and other factors like lesser technical skill , cross
> wind or effects of the stream come in to play. In these cases the boat
> does not go perfectly straight and the fin acts as a brake by meeting
> the flow of water at a less than optimal position.
> ") which seemed to my non-engineer mind to be suggesting that the
> carbon fin would help you go round corners better!
Nick, a fin (any fin) will produce lift when presented with an angle of
attack greater than zero. If the fin is placed aft of the longitudinal
center of the hull, this lift force will tend to steer the hull back
towards a zero angle of attack. So, when in flat water, if you steer
off course a bit, the fin will help turn you back to straight.
However, in a cross current, the fin will help turn you into the
current, so you'll constantly be fighting to stay straight. Similarly,
in a cross wind, you want to point slightly off course to keep a net
straight-toward-the-finish path. However, this puts the fin into a
lift-creating situation, so again, you'll be fighting the fin to stay
pointed the way you want in order to compensate for the wind.
Lesson: fin size and location is a delicate design problem, and
adjustability would be ideal. (I think).
-Kieran
Peter Ford
Do people swap rudders for head races/bendy regattas, or are most
people stuck with rudders designed (?) for straight 2k's? and if some
people do swap, do any companies make bigger rudders to drop into
normal steering set-ups?
Peter Ford
Adriaan
>
> Do people swap rudders for head races/bendy regattas, or are most
> people stuck with rudders designed (?) for straight 2k's?
I think that most clubs here in Amsterdam swap fin/rudder only twice a
year. There is a distinct 2k season (April-July) when most crews train
on the Bosbaan 2k course with 'normal' racing fin/rudder setup and the
rest of the year training takes place on the Amstel with special Amstel
fins and rudders. Do note that I don't know if/how this is done for
boats other than Empachers, but those are the most common over here anyway.
> and if some
> people do swap, do any companies make bigger rudders to drop into
> normal steering set-ups?
I have seen these rudders in different sizes but I have no idea where
they all come from. At least one variety can be found here:
http://www.heeresboatservice.nl/winkel/divers.html
The 'special' fins seem to me like normal racing fins cut off to half
the normal height or even less, but I don't know if these are also
'made' rather than 'modified'. I do know that the vets from my club used
a self-modified fin on their borrowed Filippi 8+ at the Head of the
Charles last year to get around the corners more easily.
--
Adriaan
anto...@aol.com
That "Bullshit" is called sales......Its sales and marketing, selling a
product or .....maybe an idea? or maybe a Safety concept !! to the
user......
That user is the rank and file rower......
Seems to work for Fillipi.
Do you suggest they should do the R&D and then keep the idea all to
themselves? or maybe they could come on to RSR.
Hmmmmmm
June Kendrick
whether she likes it or not. She worries about breaking it as it sticks
up further when the boat is upside down on the rack or when being carried.
The US Men's medal winning Hudson 8 appears to have a fin very similar
in profile.
June
ncmo...@yahoo.co.uk
>Nick, a fin (any fin) will produce lift when presented with an angle of
>attack greater than zero. If the fin is placed aft of the longitudinal
>center of the hull, this lift force will tend to steer the hull back
>towards a zero angle of attack. So, when in flat water, if you steer
>off course a bit, the fin will help turn you back to straight.
>However, in a cross current, the fin will help turn you into the
>current, so you'll constantly be fighting to stay straight. Similarly,
>in a cross wind, you want to point slightly off course to keep a net
>straight-toward-the-finish path. However, this puts the fin into a
>lift-creating situation, so again, you'll be fighting the fin to stay
>pointed the way you want in order to compensate for the wind.
Kieran, thanks for the explanation - makes much more sense now!
I wonder how much use an adjustable fin would be though, given that
conditions often change from one outing to the next. As you suggest
that small changes could have a big impact, wouldn't that mean that
most people would never be able to work out what is the optimum
adjustment for those specific conditions?
Cheers,
Nick
Rob
boats and their fins, just as you get to feel the way different boats
run in different parts of the stroke. Doing this may be more important
than changing fins, or maybe a person is supposed to do both.
In the fall of 04 I went from a Vespoli Matrix 27 to an Empacher C12.
VERY different boats.
The Vespoi had lots of rocker and was relatively beamy. It looked like
a boat to carry a sack of potatoes in but I was very fast in it. It
turned on a dime (or did it turn on a shilling?), lively at the catch,
much up and down with the bowball through the stroke. Coaches hate
this and think it signifies bad rowing--often it does of course.
The Empacher wants to go straight as is well known. At first it felt
dead at the catch; now I wouldn't say that. I've developed an earlier
power curve, partly in response to the boat (partly just better
rowing). If the Empacher isn't perky at the catch it's obviously
making up for that later on in the run of the boat. It's narrower in
the beam than the Vespoli, and the hull is conspicuously wider forward
of the cockpit.
I've been encouraged by many talented rowers to put a different fin on
it (or cut a triangle out of the existing fin, so that there's less fin
impeding the turn). But after awhile you get to know what to expect
and I'm really not sure I want to fiddle with anything now.
A bigger difference in the two boats is that the Empacher is very
stable in chop. I love the Empacher, make no mistake, but I don't
think one boat is faster than the other. I mean that!
I know I've strayed from the fin discussion but I want to bolster my
argument that the physics is all good, and all true, but our adaptation
to fins and the rest of our boats is a very important factor, too.
"It's not the chariot."
The paste below is back in the technical vein, from my good friend
Carlo Zezza, top 70+ sculler & great guy.
> It's all aroma until the fin gets wet. Instead of
> theory, need to try
> different sizes and shapes, and see which goes best
> for which conditions.
>
> Here are some observations based on trial-and-error:
>
> -- What's ideal for course racing isn't ideal for
> head racing, and vice
> versa.
>
> -- it's easy to make a fin for course racing (just
> needs to keep you
> straight)
>
> -- but hard to make a fin for head racing. The fin
> needs to turn easily
> ("stall") but recover laminar flow quickly when side
> pressure is released,
> i.e. the boat stops yawing instantly when the oars
> come out of the water.
> Flat plates are poor for recovering laminar flow, a
> foil section is much
> better (NASAsmasa, it just needs to look right, with
> no knife edges)
>
> -- continuing from the preceding, the fin is high in
> the water at the finish
> when yaw recovery is needed: The foil section needs
> to continue fairly deep
> below the hull into undisturbed water, especially if
> the fin is mounted way
> aft
>
> -- behavior in cross winds can be a major factor on
> some courses (e.g. the
> last 0.5k of the Schuylkill downstream). Ideally the
> boat won't weathercock
> either way in a crosswind, i.e. crosswinds will just
> drift the boat
> sideways. Depends on fin size and location. Only
> way to find out is to put
> the fin on the boat and go looking for a stiff
> crosswind
>
> Logic says that forward mounted fins (King boats)
> need to be bigger, and
> small changes make less difference. If the fin is
> far back (my Resolute)
> the fin can be smaller with less wetted surface, but
> small changes make a
> big difference. Really.
>
> That's my two-bits worth,
>
> Aloha,
>
> Carlo
>
J Flory
I too made the Vespoli-to-Empacher transition (with a brief diversion
to Hudson) and my experience parallels Rob's, I agree with all of the
above, and have a few details to add:
(1) hulls with more inherent directional stability are probably less
sensitive to changes in skeg size than hulls that tend to wander more
(but thanks for continuing to use the stock skeg as that gives me at
least a prayer of beating you, Rob)
(2) a friend worked for Resolute and owns the Resolute HW 1x prototype.
It originally had THREE skeg boxes in it so they could test different
skeg locations. Even builders that do intensive design engineering
have to resort to empirical tests for some things.
(3) in agreement with Carlo's thoughts, this friend uses a larger skeg
for sprints and a smaller one for head racing
bill
>
> I too made the Vespoli-to-Empacher transition (with a brief diversion
> to Hudson) and my experience parallels Rob's, I agree with all of the
> above, and have a few details to add:
>
> (1) hulls with more inherent directional stability are probably less
> sensitive to changes in skeg size than hulls that tend to wander more
> (but thanks for continuing to use the stock skeg as that gives me at
> least a prayer of beating you, Rob)
> (2) a friend worked for Resolute and owns the Resolute HW 1x prototype.
It has an ABS plimsoll mark on it, yes?
Carl Douglas
It's very simple, Anton. Just tell the truth about the product.
Carl Douglas
> I think you make adjustments to the turning capabilities of different
> boats and their fins, just as you get to feel the way different boats
> run in different parts of the stroke. Doing this may be more important
> than changing fins, or maybe a person is supposed to do both.
>
>
> I know I've strayed from the fin discussion but I want to bolster my
> argument that the physics is all good, and all true, but our adaptation
> to fins and the rest of our boats is a very important factor, too.
> "It's not the chariot."
>
> The paste below is back in the technical vein, from my good friend
> Carlo Zezza, top 70+ sculler & great guy.
>
>
>>It's all aroma until the fin gets wet. Instead of
>>theory, need to try
>>different sizes and shapes, and see which goes best
>>for which conditions.
>>
>>Here are some observations based on trial-and-error:
>>
>>-- What's ideal for course racing isn't ideal for
>>head racing, and vice
>>versa.
<snipped>
>>
>>That's my two-bits worth,
>>
>>Aloha,
>>
>>Carlo
>>
>
>
What a great guy is Carlo!
He was over here at the end of '05. He comfortably won his division of
the Scullers' HoRR on the Tideway - in one of our singles. And before
the race he put a lot of effort into learning the best course to follow
on this wide, winding, ebb-current course.
He's coming over in the summer to have a crack at Henley Vets - in the
same boat.
J Flory
bill wrote:
>
> It has an ABS plimsoll mark on it, yes?
Yes it was black and had plimsoll marks last year but now it's white
with blue decks.
Rob
P.s. In my lengthy tome on fins I forgot the most important element
for
fall head racing: the forward edge must rake 40ยบ or more from vertical
or it
will pick up the floating leaves that have fallen off the trees.