Tape on Oar Shaft for Blade Depth

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Jared

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May 13, 2008, 9:13:00 AM5/13/08
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How does one determine the appropriate, i.e., quantatative
measurement, of how far up the oar shaft the water level should be
during the drive? I am interested in doing this both for sweep and
sculling oars for my team, but cannot find any numerical
representation. I could always eyeball it, but that doesn't seem very
precise.

RoC...@gmail.com

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May 13, 2008, 10:03:44 AM5/13/08
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Get a copy of Volker Nolte's "Better Rowing." I think there's
something in there that you can use.

paul_v...@hotmail.com

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May 13, 2008, 11:39:34 AM5/13/08
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On May 13, 6:13 am, Jared <jaredcourt...@gmail.com> wrote:

Our club has taped about 30cm from the blade attachment, but it's not
nearly enough for either sweep or sculling. Oh.... IMO. [:o)

I put tape where the balance point of the oar is (on all my personal
oars), to make carrying them easier (Nice to know where to hold
them.), and as long as that tape doesn't go underwater, depth is not
an issue. [;o)

- Paul Smith

carolinetu

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May 14, 2008, 5:52:52 AM5/14/08
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The way I do it when I'm coaching is to get the crew to sit with their
blades square in the water perpendicular to the boat, let go, and see
what depth they float at. I make them do it at the catch and the
finish as well, so they can see what height their hands should be.

Caroline

Carl Douglas

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May 14, 2008, 7:13:35 AM5/14/08
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I am sure that's good advice for novices, who need an easily defined &
managed criterion. But it suggests that the mere accident of buoyant
displacement in an oarblade whose thickness was set by a FISA regulation
is appropriate to define a key parameter with strong influence on the
complex hydrodynamics of the stroke.

In other words, it presumes that you should only row the top edge of the
blade just below what would be the undisturbed surface if you weren't so
busy disturbing it. Yet we all know that, if you row it deeper, it
feels more solid ("heavier"). When it feels more solid that's because
it's slipping less. And when it slips less, the blade is more efficient
& you become a more effective boat mover.

It is of course much easier, & initially convenient, to view the stroke
as a quasi 1-D horizontal action connecting between 2 vertical
movements, but this has to limit performance potential. However, such
is the desire of rowers & coaches to "define" what constitutes the
"right" way to row that rules learned early to help you into the sport
then become unbreakable dogma which restrict & limit subsequent
development. Such dogma is even used to criticise the performances of
world-beaters. Thus of more than 1 champion sculler have we heard
average rowers saying sagely, "Oh, he'd have won by even more if he
didn't row so bloody deep", & "Look how much he's losing by looming" -
which is utter twaddle in both cases.

Cheers -
Carl

--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: http://tinyurl.com/2tqujf
Email: ca...@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)

carolinetu

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May 14, 2008, 10:33:41 AM5/14/08
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> Email: c...@carldouglas.co.uk  Tel: +44(0)1932-570946  Fax: -563682
> URLs:  www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)- Hide quoted text -
>
> - Show quoted text -

Carl, I take your point. I do mainly coach novices and spend a lot of
time trying to teach them not to attempt to dredge the bottom of the
river!

If you go in deeper, would that not shorten the arc of work? If so,
this would surely be less efficient, particularly for the sort of
people I coach, who tend to row short anyway and are not as fit and
strong as your champion scullers?

I guess what this boils down to is that perhaps there is no ideal
depth which suits everyone. But I like the idea of taping the shafts,
which would certainly help them to attain consistency as a crew.

Caroline

paul_v...@hotmail.com

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May 14, 2008, 11:56:32 AM5/14/08
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> > URLs:  www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)-Hide quoted text -

>
> > - Show quoted text -
>
> Carl,  I take your point. I do mainly coach novices and spend a lot of
> time trying to teach them not to attempt to dredge the bottom of the
> river!
>
> If you go in deeper, would that not shorten the arc of work?   If so,
> this would surely be less efficient, particularly for the sort of
> people I coach, who tend to row short anyway and are not as fit and
> strong as your champion scullers?
>
> I guess what this boils down to is that perhaps there is no ideal
> depth which suits everyone.  But I like the idea of taping the shafts,
> which would certainly help them to attain consistency as a crew.
>
> Caroline- Hide quoted text -

>
> - Show quoted text -

If not at the novice level, where should accurate information be
instilled?

Let them dredge away, survival instincts will assit in their learning
two useful things; how to extract the blade cleanly from a deep drive,
and what a more appropriate depth should be.

Since you say "there is no idea depth which suits everyone", why would
you "like the idea of taping the shafts" to "attain consistency as a
crew" (Presumably using the tape as a guide). I do think it's good to
have consistency as a crew, but as far as blade depth goes, they all
need to be at least "deep enough" to begin with.

I've been having to fight my rowers on this the whole season, as they
have been well ingrained in the "floating level", "30cm of shaft",
etc... mantras that they have heard, and exaggerated dutifully to
create great washy puddles that send a lot of water backward while not
advancing the boat much.

I've not seen a Dreher Sweep oar, the "floating level" might be about
right for their Sculls, but it is far deeper than any C2 blade will
float. I suspect that the dreher blades, if not attached to a shaft
would actually sink (even when feathered there is no part of the blade
above the surface if they are left to their own buoyancy), whereas the
C2's float very well.

My next project is to convince our boathouse manager that increasing
spans and reducing inboard will not "lower the gearing", but make the
sculling boats more comfortable, and likely better performing as a
result.

- Paul Smith

Carl Douglas

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May 14, 2008, 12:38:31 PM5/14/08
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And that was exactly the point I'd hoped to make, Caroline. Novices
need limits which more experienced folk should dispense with.


>
> If you go in deeper, would that not shorten the arc of work? If so,
> this would surely be less efficient, particularly for the sort of
> people I coach, who tend to row short anyway and are not as fit and
> strong as your champion scullers?

That conjured a fleeting impression of a very round, short-armed person
reaching up above their head for a catch that dredges the bottom ;)

The less hard you row, the less you need to dig deep because the less
the likelihood of actually disturbing the water. The harder you pull,
the greater the benefit from going deeper, especially around mid-stroke.

>
> I guess what this boils down to is that perhaps there is no ideal
> depth which suits everyone. But I like the idea of taping the shafts,
> which would certainly help them to attain consistency as a crew.
>

Yes, but I'd like that depth to be where you go to at the deepest point,
no where you go to throughout.

Cheers -
Carl


--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: http://tinyurl.com/2tqujf

Henry Law

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May 14, 2008, 1:47:47 PM5/14/08
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carolinetu wrote:

> If you go in deeper, would that not shorten the arc of work?

<expert status="not">
Deep is up-and-down, let's call it Z; the arc is in the XY plane. Since
they're orthogonal surely neither affects the other? (Unless there are
engineering issues at the pivot point, some kind of interference if the
blade is deeper).
</expert>

--

Henry Law Manchester, England

Charles Carroll

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May 14, 2008, 9:44:55 PM5/14/08
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Paul -

Is there really "no ideal depth which suits everyone?"

I had presumed that the ideal depth is as simple as this. Enter the blades
only as deep as they need to be to hold on to the water?

If the blades slip, if you see air entrainment following the blades as you
pull, they are not deep enough. And aren't the blades, if you enter them
deeper than this, unnecessarily deep?

Cordially,

Charles

kda...@kidare.com

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May 15, 2008, 4:11:14 AM5/15/08
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> > > URLs: www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)-Hidequoted text -

I think there are 2 reasons why going deep may upset a novice crew:

1. Going deeper than the naturally buoyant level of the blade requires
the rower to hold the blade deep during the stroke, adding the lifting
effort from the shoulders to all the pulling effort they are already
exerting. For fit athletes this may not be an issue (though even then
it may), but for the inexperienced, I believe they will relax more
when purely focussing their physical efforts on drawing the blade. In
this case, ideally the naturally buoyant level of the blade should be
deep enough (as already discussed).

2. If the draw of the blade includes a vertical component during the
drive (as opposed to just at the catch and finish), I believe this
will add to the vertical forces on the gates affecting balance. During
the drive this may not have a great effect, but it will be very
difficult for novices to keep these forces balanced between both sides
of the boat towards the finish, where imbalance has worse consequences
for the recovery. Again, an experienced crew may be able to feel the
forces an adjust for any imbalance (though even then they may not).

I think my preference is for as little effort as possible for holding
the blade at the correct height, and that blades should preferebly
float to the required depth when square. I'm sure it would be possible
to attach small weights to the looms to achieve this.

Regards
Kit

paul_v...@hotmail.com

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May 15, 2008, 11:21:41 AM5/15/08
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On May 14, 6:44 pm, "Charles Carroll" <charles_carr...@comcast.net>
wrote:

Well, now that you improved on the definition of ideal depth, I'm
inclined to say "yes". The interesting caveat is that it would appear
that while it's obvious what is "too shallow", "too deep" would be
very difficult to define. And the fact that there is no "ideal force
for everyone" to put on the handles, the "ideal depth" will vary based
on that. Not to mention that as the boat speed varies, the variables
all change.

That said, "too deep" is better than "too shallow". The factor that I
consider most important is how the force is managed, but that has a
large dependency on the skill of the rower to get the blade quickly
covered prior to beginning the onset of handle force, for if they even
slightly tear the surface on the way in, the subsequent connection
will likely never happen. I took out a rather novice sculler on
Tuesday (they have been taking club classes for a season and have the
basics covered), we had perfect smooth conditions, and while rowing
individually he decided to put in some power so I watched the speed to
see where it stabilised. When he tired and decided to stop, he
confirmed that he was "trying to go fast", so I asked him to sit easy
while I brought the boat to the same speed, then as we were travelling
along the conversation was about how both the rate and apparent effort
could be so much lower for the same speed. The most obvious change
was the temporal length of the Drive impulse, allowing for a more even
system speed, and since the peak force is lower the overall feeling
was more like a "paddle" than a "power piece". Which, to tie it back
to the original topic, would require less blade depth while still
avoiding any tearing of the water.

- Paul Smith

paul_v...@hotmail.com

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May 15, 2008, 11:39:43 AM5/15/08
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> > > > URLs:  www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)-Hidequotedtext -
> Kit- Hide quoted text -

>
> - Show quoted text -

1. This rings of the same tone as "letting the blade fall in under
the force of gravity", which we know can not get the job done quickly
enough. So prehaps not bad as a "mantra" but results will vary
because it's not really what must happen.

2. Have your crew swap the blades to the opposite side (assuming
cleaver style blades) and row that way for a while, until they
acclimate to where it feels "normal" to them. Then swap back to the
"normal" side and they will relax from some of the defects in their
stroke. (This basically amounts to an instant pitch change, and
illustrates the type of forces we unconciously place on the handle
through the drive.)

The additional weight on the loom is an interesting idea, but changing
the swing weight of the oars and the addition of outboard mass, will
have very undesireable effects if your crew does not have consistent
and stable handle heights. I absolutely love the feel of wood oars,
they have more mass, and that allows an additional degree of control
if one can take advantage of it, but the same control that can be an
advantage becomes a disadvantage when the actions of the rower are not
well controlled.

- Paul Smith

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