> I don't think the relatively small changes you're making to your
> blades/oars are very significant & I don't think they materially change
> the propulsive efficiency of the blade in the water. What really does
> change that is blade depth. And that's something you can change without a
> screwdriver, just by choosing to pull higher through the middle of the
> stroke, & it makes a big difference to efficiency.
Carl,
I am very glad that you think so. I have been told so often that my rigging
is all wrong and that I am over-geared. It seems to me that in my little
world current fashion has it that a decreased spread, decreased outboard,
enlarged blade surface area, and more flexible oar shaft will produce more
speed. I just don’t see it. It hasn’t been my experience. Indeed it seems to
me that all this amounts to is materially trying to change the propulsive
efficiency of the blades in the water in order to produce a higher rate.
As for blade depth — I could not agree with you more. “… choosing to pull
higher through the middle of the stroke … makes a big difference to
efficiency.” But doesn’t increasing the outboard also bury the blades a
little deeper? And if so, increasing the outboard must then make the blades
more efficient.
Do you recall that video that I made a few years ago about Hand Path During
the Drive? It is the most boring video ever uploaded to YouTube. I ask
because I show Ivanov’s hand path during the drive and quote you on why he
is pulling higher in the middle of the stroke.
Now on to the irrelevance of rateng to time spent in the water:
> higher blade efficiency must mean a slightly longer immersed time per
> stroke, so you must proportionately reduce pressure, _not_ increase it to
> get the stroke time down, & very slightly reduce the recovery time, there
> is no need for rating to fall
And with that little paragraph you have taken me to a new and higher level
of sculling.
But I have to explain. I watched the OP’s video and compared it to the video
of Ivanov’s sculling. What a difference!
If you look at the videos in real time, both Ivanov and the OP get long and
have quick catches. The OP, however, as you say, seems to take “several
small actions which aren't connecting load to blade.” To my eye it looks as
if the OP in the beginning phases of the drive is not producing the
propulsive efficiency that he could and should produce.
Ivanov, in contrast, produces propulsive efficiency right from the start of
the catch. He just connects the load to the blade so much faster than the
OP.
So my next question was why? What is Ivanov doing differently?
I reproduced Ivanov’s video in slow motion, then reproduced it again in even
slower motion. If you look at the video in real time Ivanov’s sculling is
awesomely smooth. In very slow motion, however, Ivanov’s smoothness becomes
more jagged. In fact in the video in very slow motion Ivanov very briefly
pauses after the blades are covered. He holds the blades in place with
nearly no perceptible movement of his hands and body almost as if he is
waiting for something.
Isn’t there an unvarying and immutable law of rowing which states that the
rowing stroke is a continuum and that one must never purposely interrupt
this continuum to wait for something to happen? Yet Ivanov is definitely
waiting, albeit the wait time is so brief that you will never see it in real
time. It is only visible in very slow motion.
So what is Ivanov waiting for?
I immediately thought of something that you have said and have been saying
for years — namely, you should not push off the stretcher until you have
established “essential tensile connection between the mass of water behind
the backs of the blades and the backs of the blades themselves.”
So Ivanov is much faster at connecting load to blade. In other words, Ivanov
produces useful power more quickly and for a longer time and does our OP.
So Friday, the last time I went sculling, I put this to the test in my
on-water laboratory.
My whole focus was on not losing length at the catch. To do this I drew the
shell underneath me. Then, when the oar handles were at the furthest point
towards the stern, I put the blades in the water and held them in place
until I established the “essential tensile connection between the mass of
water behind the backs of the blades and the backs of the blades
themselves.” Only after I felt this connection did I push off the
stretcher.
In other words I did something which was quite forbidden. Once I had placed
the blades and they were fully covered, I held them in place and waited. I
even pushed the oar handles ever-so-slightly sternwards after the blades had
been fully covered. Would the Gods of sculling open the heavens and hurl a
lightning bolt that would pulverize me into a pile of ash, I wondered?
But nothing of the sort occurred. Instead I only stayed in the water
slightly longer with a little better propulsive efficiency, particularly in
the beginning phases of the drive.
Ok, so next I followed your suggestion.
You write: “Maybe the simplest example of the irrelevance [of] rating [to]
time spent in the water is the demonstrable fact that any sculler who puts
their mind to it can paddle light at rates well over 35. It’s just a matter
of not wasting time & not dwelling over the catch — the recovery is not for
taking a rest, nor for ‘letting the boat run,’ but about attacking the next
stroke, just as Ivanov did.”
So this is what I did. I paddled light and used the recovery to produce a
higher rate.
I am still finding it hard to believe the results. The readout on the
SpeedCoach said that I had achieved a goal that I have been working on for
months.
With warmest regards and many thanks,
Charles