More Speed

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Bob

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Nov 21, 2021, 4:56:57 PM11/21/21
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I (finally) realize the need to research past conversations before starting new ones. Most of the time the subject has already been addressed given the long history of this group. For the same reason there is also a tendency to forget past discussions more than a few years old.

The trigger for this was coming across a research paper on speed strips for oar shafts. It turns out the subject was discussed years ago and expanded to other incremental changes that can improve speed.

It seems that one can break these improvements down into technique and equipment.

Could we come up with a list of ten to twenty equipment tweaks that can each give an incremental increase in boat speed for sweep boats based on past discussions? It would be interesting to see that list.

Examples are:
Steering systems - The obvious one is from Carl Douglas but others?
Oar shaft shape/diameter, minimum diameter, elliptical - whose?
Speed Strips on shafts - patented and unavailable?
Oar shaft stiffness
Riggers for reduced drag - which types?
Minimizing rower drag - how?
When to roll up? - gray area involving technique
The importance of balancing boat power?
Rigging - front load (sweep)?
etc etc.

Surely there must be many coaches out there who understand the importance of incremental improvements and who might want to try some of the ideas from such a list if it were readily available.

Thanks,

Bob




carl

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Nov 22, 2021, 9:10:33 PM11/22/21
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Sadly, to be seen tinkering with tech is not most coach's top priority.
After all, they have first to get the crew up to speed, & always there
is a little bit more to do in that direction.

What is needed is an engineering support team, or a team engineer, who
fully understands the physics & mechanics, allowing the coach to address
the myriad aspects of bringing the crew together & to peak performance.

The first appearance of speed strips on oars was with the GBR Olympic
men's eight in 2000, & it's not patented so anyone can and should do it.

Shaped shafts (e.g. elliptical section) have been used by Dreher.

Rigger drag - we made a wind tunnel & performed comparative drag tests
with pleasing results.

Rowers & windage of boat. Back in '78 we made a shaped deflector to go
ahead of bow's back on the W2x which went to Karapiro. But they never
took it out of the box! Similar devices have been seen at international
events more recently. In 2000, as well as addressing oar-shaft drag, we
made recommendations for reducing the open space ahead of cox, which
were implemented in Sydney. Before that, a Dutch 4- wore tops with
smooth hoods. And lots of hair is not exactly a good idea either.

The problem is in getting people to measure or accept these effects.
While one can calculate & quantify the benefits from various small
changes, I think crews & coaches are looking for dramatic improvements
rather than hard to assess marginal gains, & these aren't easily come
by. So good ideas have short lives.

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: tinyurl.com/2tqujf
Email: ca...@carldouglasrowing.com Tel: +44(0)1932-570946 Fax: -563682
URLs: carldouglasrowing.com & now on Facebook @ CarlDouglasRacingShells

Bob

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Nov 22, 2021, 11:57:18 PM11/22/21
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Carl,

That was part of the reasoning behind a list that you experts can more or less agree on. It makes it easier
to try things and in a sense, they are independent of the crew.

For example which riggers performed best in the wind tunnel or is that another search into the annals of Rec Sport Rowing?

I realize it may be to big of an ask and the biggest gains are in the crew but so many races are so close!. It doesn't take
,many fractions of a percent to add up.

Bob

Phil

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Nov 23, 2021, 6:19:32 PM11/23/21
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I'd suggest that good, accurate telemetry data and repeatable conditions are one of, if not the biggest barrier to wider adoption of evidence-based technical improvements to performance. Track cycling, F1 et al. have all coped well with that conundrum. Probably requires a new approach to succeed in rowing - indoor 2k+ conditioned race courses anyone?

Cheers,
Phil.

Peter

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Nov 24, 2021, 1:01:01 AM11/24/21
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Definitely onto something there - Indoor pursuit rowing! The 'Remadrome'? The 4 scull pursuit? It'd be a brilliant spectator sport if one can figure out how to bank the course <g>
I'll get my coat...
pgk

Bob

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Nov 24, 2021, 4:47:58 PM11/24/21
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This thread is getting to serious for me. Let's start with two possibilities for increasing intrinsic boat speed.

1. Optimized Fin/rudder assemblies
pros: a. sharper turns with less energy loss
b. less energy loss when steering a straight course in the face of off center winds and power
imbalance in crews.
c.???
cons: ????
Who makes them and are any considered knockoffs of others original work? i.e. which are original
and which are knockoffs?
Are there any empirical results for performance gains using the above?

2. Oar shaft treatments for improved headwind performance
Which is better (how much?):
a. Smaller diameter vs larger diameter shafts.
b. Elliptical shaft vs larger diameter shafts.
c. Elliptical shaft vs smaller diameter shafts
Question: Is the elliptical shaft "good" in one orientation and "bad" in the other?
Does the difference in shaft speed relative to the wind between drive and
recovery have much of an effect on the drag force in the two positions?
https://www.durhamboat.com/oars/sculling-oars/elliptical-sculls/
Expand the graph in red on the webpage. It looks like there is going to be a
lot more drag when the oar ellipse is across the wind. Is the overall result
better than a small round shaft?
https://www.researchgate.net/publication/332859676_Measurement_of_Drag_Coefficient_for_an_Elliptical_Cylinder
What are the pros and cons:
a. Durability of small shafts
b. Relative stiffness of small shafts - does stiffness matter?
c. Drag reduction at different headwind velocities for small shaft vs ellipticals?

In all the years that the above two have been around, is there any consensus or conclusions on the merits?

What about speed strips? (worlds longest URL!):
https://pdf.sciencedirectassets.com/278653/1-s2.0-S1877705816X00161/1-s2.0-S1877705816306452/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEJ7%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaCXVzLWVhc3QtMSJHMEUCIDfX41KsgyprpO2YDL33TfISp8JfDuXhV9AbkfCKnwpNAiEA6xeBnndmqdNf1DzEe2xGQNaSRW0DELY4aS65nxXYmosq%2BgMIZhAEGgwwNTkwMDM1NDY4NjUiDKHmD3pjKQ6o4jp%2BeCrXAyaWoTek%2B40SswYftaJW9ewfZUywHxMlmaaEPTmv0ZbaHppZTDwy3FqaHlTT%2FMCjYOfecVUMpxyYq%2FNUPAmor%2BMUXdnRT5No5ECbOfeKJ4btU9i3rm3qpgdwMOB467ETurbqOtXGtZzpeeDPwc0KRzr7NHwgYjbGjNVDwulcehlJs5z0gueNiejmE%2FqJ6A4VFjGxW1ofB7wnX5vhWHoiLBjjqbuRCfhoEjEYhgurKbKOgmB%2BtIKx1YkPbTjwB9XVc77Bapcoq44pClH6dcf9wPzWuD9cEDiqefN6iOWRuPOx7g1Q4r4VKJbc1tWeIgr2OyUjd0iYflx70lJIvlJxcbAQBkL3WWvJPfZRIfQE3xjYhHkK%2FQw0hy3lBvt2jzbWGbVlT90ZHfITMRJgSJh6eMrMz8eItPlwprM2WNfsINbwLPLjeeyHN84p69D3xe9UouZOmh2w%2BfI9E6nbJpT2U7Gz97J3FyDsR%2F1BuLj9ZDY06Q0yo400XcRs1WH7jTjyCf%2B%2Fsuf6beuIfnWD9OzrQtj0ADkrKnoDssJcCP8KHIV4Lb4HrjrXQGX4eOBEMKeTc9wVFgaiDoeGB%2Bgnnh%2Fg422Fwf%2BsXx5bcur0bgnUbKsz95hXhuL2bjDN1vqMBjqlAVz1Zhi4gO7yHI%2FV8Y0HAPM5QtQb3gLLc%2FaydiU46I5WpF8Hyre%2FEAJutuN7EnJqN6R4yOw2b7omfWlq7CO6tTd0FITzIbuG9G4y3FHWe%2BPiEs%2F0FLEHiWtRw8nOTPwYDvBRPHLB5PRmFkQiVBW1npqR4oJ8FuYquQ8ctd3ZNwtouyvqUmG8pAu%2FpWXuk9pi%2BaHRW%2B7Zx9qdgy8dFus7YQJMJ0i1zQ%3D%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20211124T214030Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTYSF3OK64V%2F20211124%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=d137f5b546d05f530ecf3535d347c8b620a06314a71dd67518ec81168394a93f&hash=b42ad45fe17285148bea1514066ea0ee769a8fd5c57c2dd553968736b59b95fb&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S1877705816306452&tid=spdf-eed398e4-b3d8-4f5f-9b7e-efbe2b12ec41&sid=c4a14903138bd541c36a3db3467bb9b77f51gxrqa&type=client

Bob

Andy McKenzie

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Nov 25, 2021, 4:33:07 AM11/25/21
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Commenting as an observer of seriously fast crews, who has never coached one or rowed in one, I think you left off the one thing you already have, and that doesn't cost you money - rigging.
I knew a coach who was, successfully, obsessed with eking out every marginal gain he could from equipment. They invested in shiny new things, and telemetry and videoing every session before it was fashionable, but they also adjusted each rigger, each foot plate, each seat height and each blade to 'fit' the rower in that seat. If you have an eight with eight seats with identical span, gearing, foot plate height etc. you are either sub-optimum for everyone, or you are running a secret cloning program.
Unfortunately to work out the optimum rigging, you probably need the telemetry and video - so my 'doesn't cost you money' argument breaks down at that point.

Bob

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Nov 25, 2021, 12:23:31 PM11/25/21
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Andy,

As an observer of less than seriously fast masters crews, I can still call up images from a launch of tall rowers trying fit in a boat and looking like they are rowing at half slide. My question: if one gave them their own specially geared oar without changing the rigger, could they be able to make decent strokes and feel comfortable doing it?
I can't see anyone adjusting the rigger for them since the seat may be shared by other rowers.

Some Dreher oars have an on-water adjustable sleeve and handle. Croker just announced a quick release collar so I wonder if the above question has merit?

Thanks,

Bob

Andy McKenzie

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Nov 26, 2021, 9:14:06 AM11/26/21
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One of the things I learnt from the 'Boys in the Boat' book about the University of Washington rowers at the Berlin Olympics, was that in the 1930s the UK crews were giving stroke a shorter (or thinner) blade than the rest of the crew, which has been discussed before on RSR - and is outlined at https://heartheboatsing.com/2013/12/04/malcolm-cook-shaved-blades-were-used-in-the-boat-race-in-the-1920s-and-1930s/

With a masters crew adjusting gearing to match physique and strength would be easy enough to try. It should help keep time in the water consistent. The potential downside is probably imbalance, but I have rowed enough in 7s when we haven't had enough people for an 8 to feel that as long as the crew are in time the boat can be be sat and will track straight.

Bob

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Nov 27, 2021, 12:17:18 PM11/27/21
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Not a lot of interest in coming up with a large list of speed freebies so here is my proposed list based on advice received and from past posts:

1. Carl Douglas AeRoFin and Canard on shell.
Helps with turns, crosswinds and side to side power imbalance (yaw)
2. Anyone's skinny oar shafts or Dreher Ellipticals
Helps most in head winds.
3. Late Blade Rollup
Reduces blade resistance in headwinds. Helps in rough water.
4. Rigging
A must to optimize each rowers contribution to the boat but
not easy in a Masters Program. Proposed compromise is dedicated oars
for unusually sized rowers or Dreher on-water adjustable oars.

Thanks for the advice and comments,

Bob




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