Increasing Outboard

Increasing Outboard

Post by Charles Carrol » Fri, 15 Mar 2013 03:43:23


Dear all,

I have a quick question for the RSR Brain Trust.

Can you compensate for a reduced catch angle by increasing the outboard?

Cordially,

Charles

 
 
 

Increasing Outboard

Post by Charles Carrol » Fri, 15 Mar 2013 11:29:06

I dont know. Perhaps I should elaborate.

I had always supposed that the important reason for getting long i.e. for
using as great a catch angle as you are capable of achieving is that this
permits you to keep your blades in the water longer. In my simple mind if
your blades are in the water longer, you can apply power longer. And if you
can apply power longer, and hold on to your rate, then wont you move your
shell faster?

Ok! But using a longer outboard also keeps your blades in the water longer
leastwise this has been my experience. So if you are height challenged, as I
am, and cant get a really great catch angle, why not just increase the
outboard?

Is there a difference in gearing between using a greater catch angle as
opposed to using a longer outboard?

Somewhere I believe that Valery Kleshnev has addressed this issue. I think,
if I am remembering correctly, he has found that a longer outboard reduces
handle velocity. I seem to remember Dr. Kleshnev's saying that handle
velocity is the telling measurement in this issue?

 
 
 

Increasing Outboard

Post by thomas.k.car.. » Fri, 15 Mar 2013 17:44:08

Quote:

> Dear all, I have a quick question for the RSR Brain Trust. Can you compensate for a reduced catch angle by increasing the outboard? Cordially, Charles

rowperfect had a article recently that may help with your question

http://www.rowperfect.co.uk/rowing-rigging-changes-you-can-do-to-chan...

Long story short, the best way of increaseing all angles (catch, finish) is to reduce inboard and span equally and adjust the stretcher to keep hands the same at finish

 
 
 

Increasing Outboard

Post by James H » Sat, 16 Mar 2013 01:52:41



Quote:
> I dont know. Perhaps I should elaborate.

> I had always supposed that the important reason for getting long i.e. for
> using as great a catch angle as you are capable of achieving is that this
> permits you to keep your blades in the water longer. In my simple mind if
> your blades are in the water longer, you can apply power longer. And if you
> can apply power longer, and hold on to your rate, then wont you move your
> shell faster?

> Ok! But using a longer outboard also keeps your blades in the water longer
> leastwise this has been my experience. So if you are height challenged, as I
> am, and cant get a really great catch angle, why not just increase the
> outboard?

> Is there a difference in gearing between using a greater catch angle as
> opposed to using a longer outboard?

> Somewhere I believe that Valery Kleshnev has addressed this issue. I think,
> if I am remembering correctly, he has found that a longer outboard reduces
> handle velocity. I seem to remember Dr. Kleshnev's saying that handle
> velocity is the telling measurement in this issue?

Charles,

I will use my simple brain to say how I see it until someone with more
knowledge comes along to correct me :)

Longer outboard will affect the gearing. you have a worse lever (work
point further from the pin) - and for the same rate the the blade will
be travelling further, which to me means that it must also be
travelling faster (longer journey, same rate, harder lever).

I think though that a longer outboard would actually result in a
reduction in your ability to comfortably rate higher at a comfortable
pressure because the work per stroke required to hit the higher rate
is higher.

I do not have the maths brain, but I think that there is a sweet spot
for each sculler.

In my head I see it as "Which do I want" - an ability to comfortably
sit on 32, or 28 with 10% more useful angle (due to increase in
outboard).

Then another option has been proposed in the rowperfect article below
is reducing the span - i.e. in the UK this means the distance between
the two pins. This again increases the gearing in much the same way as
increasing the outboard as it moves the pin away from the outer end of
the blade, increased time in the water will again mean more work to
achieve the same rate.

Where my brain is not able to compute, is the difference - lets say in
a minute you get 10% advantage from the outboard (I have plucked this
from the air) then you are at rate 28 getting the equivalent of 2.8
strokes increase, whereas if you rate 32 then you are getting 4
strokes.

The bit that I cannot do the maths for is that the angle gain you have
is sweet spot in terms of converting work into forward movement(as I
understand it more lift and less slip) whereas the '4' strokes is a
mix of this.

Also, at a higher rate you tend to use less 'power' strokes.

I have been experimenting with this and find that I benefit more from
the ability to rate higher. I put less power per stroke and more
strokes and this tends to favour my physiology (ligthweight and short)

I have reduced my span and increased my inboard (overlap).

I have done this by using clams to bring my overlap up by 10 mm each
side (i.e. total change of overlap 20mm) which means that I can easily
change back and forth to see what it feels like.

I reduced the span first (to 158) and felt a slight increase in
gearing - rowed with this for 4 weeks and struggled at 28. Then
increased the overlap and can now sit comfortably at 30 and am
beginning to feel comfortable at 32.

having exposed my understanding of how I think this works I look
forward to a more expert analysis - as I do often find that I work
within the theory of what I understand at the time (I now draw the
boat towards me on the recovery and feel much more in control!) which
I only discovered (by being corrected on here) by exposing a miss-held
belief the last time!

James

 
 
 

Increasing Outboard

Post by Charles Carrol » Sat, 16 Mar 2013 02:37:36

Tom,

Here are the numbers that according to Valery Kleshnevs Rowing Speed and
Rigging Chart are Traditional: 287/160/89.

Here are the numbers for my current rigging: 288/160/87. As you can see
these numbers are nearly identical to Dr. Kleshnevs Traditional numbers.

Here are the numbers Dr. Kleshnev describes as Innovative: 269.5/152/84.5.

Dr. Kleshnev says that for someone of my height the last numbers are
optimal for achieving the maximal boat speed in sculling.

To rig for these optimal numbers I would have to order new riggers and oars.
Is it really worth it?

With my current riggers and oars I have played with rigging numbers quite a
lot. I have moved the pins inwards as far as they would go, shortened my
oars as short as I could make them, and decreased the inboard accordingly
(always keeping an 8cm overlap). I also have done the opposite i.e. moved
the pins outwards as far as they could go, etc. And I have trialed lots of
combinations in between. And frankly I havent noticed all that much
difference.

What I am really questioning is this: is it really true that shorter rowers
can benefit from using shorter oars?

Why not just come to terms with the fact that I am short and that I am just
going to have to make the best of traditional rigging numbers?

I have had a close friend tell me to stop paying attention to all the
pseudo-scientific tosh people tell you about load. The main thing is that
you should be comfortable with your rigging.

And frankly the more I scull the more I find myself coming to his point of
view.

But I also concede that I have close friends who argue to the contrary

Cordially,

Charles

 
 
 

Increasing Outboard

Post by Charles Carrol » Sat, 16 Mar 2013 02:43:48

James,

True, a longer outboard does affect the gearing.

But doesn't a greater angle at the catch also affect the gearing? Isn't this
the reason why you start out sculling short when doing racing starts -- i.e.
that you want to start the race in a lower gear and only move to a higher
gear as you pick up speed?

So why not row short with a longer outboard?

Cordially,

Charles

 
 
 

Increasing Outboard

Post by James H » Sat, 16 Mar 2013 03:02:37



Quote:
> James,

> True, a longer outboard does affect the gearing.

> But doesn't a greater angle at the catch also affect the gearing? Isn't this
> the reason why you start out sculling short when doing racing starts -- i.e.
> that you want to start the race in a lower gear and only move to a higher
> gear as you pick up speed?

> So why not row short with a longer outboard?

> Cordially,

> Charles

I think you row short at the start to get the rate up - like a skier
doing short spole pushes to get momentum up and then lengthening out.

And this is what I mean by a sweet spot - there is a trade off with
rate and length - typically I see scullers going off at 40+ but they
always seem to settle mid 30s and then finish 40+ - I draw from this
that there is no advantage to trying to maintain 40.

Likewise, you do not see scullers with incredibly long oars rating mid
20s with enormous push per stroke.

So somewhere there is a power per leg stroke maximum and a CV power
output endurance maximum. In my rowing club, the bigger and beefier
you are the lower the rate you seem to hold and the harder each
stroke, whereas the lighter guys tend to rate higher.

They may have just fallen into the trap that this is what they are
told is the optimum!

But I think that your rigging should probably be set to assist you in
finding your sweet spot in this equation. My opinion is that it is
probably better to err on the side of rate (cleanly well maintained
rate).

So IHMO rowing "short" is only ever employed at a start to overcome
inertia and artifically get the rate up.

There are lots of discussion on C2 websites that actually rowing short
can assist in the breaking of world records on the erg and
observations of the really fast guys sometimes bear this out! (they
sacrifice length for rate).

James

 
 
 

Increasing Outboard

Post by Charles Carrol » Sat, 16 Mar 2013 03:30:45

James,

Your reply deserves more attention than I giving it. But I am short for
time, so I thought you might not think too poorly of me if I just give you
the below link, which I hope you will find interesting.

http://www.biorow.com/RBN_en_2009_files/2009RowBiomNews01.pdf

There are many reasons for rowing short. Foir example, Ellen Braithwaite
described to me one of the times she raced the Catalina Crossing.

Ellen was in a double with a friend and they had very carefully determined
how much effort they could sustain over the period of time they would have
to race. For a crude measurement of this effort they used a SpeedCoach with
an impeller to get their through-the-water splits. When the water would
became rough and their splits got worse, they shortened up and raised the
rates. Then, as they sculled into calmer water, they dropped the rates and
got longer.

By the way, this helped me to understand the reasons why through-the-water
speed is so useful. In Ellen's case over-the-land speed -- i.e. GPS -- would
have been useless.

Cordially,

Charles

 
 
 

Increasing Outboard

Post by johnflo.. » Sat, 16 Mar 2013 04:52:25

Quote:

> Here are the numbers that according to Valery Kleshnevs Rowing Speed and  
> Rigging Chart are Traditional: 287/160/89.

> Here are the numbers for my current rigging: 288/160/87. As you can see
> these numbers are nearly identical to Dr. Kleshnevs Traditional numbers.

They're not "nearly identical".  Your shorter inboard decreases your leverage and your greater length does the same.  In terms of leverage, your setup would be equivalent to 294.6/160/89.  And your shorter inboard will decrease your arc versus his Traditional setup.
 
 
 

Increasing Outboard

Post by Charles Carrol » Sat, 16 Mar 2013 11:35:43

Quote:
>> Here are the numbers that according to Valery Kleshnevs Rowing Speed
>> and
>> Rigging Chart are Traditional: 287/160/89.

>> Here are the numbers for my current rigging: 288/160/87. As you can see
>> these numbers are nearly identical to Dr. Kleshnevs Traditional numbers.

>They're not "nearly identical".  Your shorter inboard
> decreases your leverage and your greater length
> does the same.  In terms of leverage, your
> setup would be equivalent to 294.6/160/89.
> And your shorter inboard will decrease your arc
> versus his Traditional setup.

John,

Obviously I am missing something. You write: in terms of leverage. How are
you arriving at a measurement for leverage?

I used a very simple formula for Gearing Ratio. I copied it from Dr.
Kleshnev.

My sculls are Croker Oars -- S2 Soft Superlights with Slick blade, 285
+/-3cm length, zero degree pitch, asymmetric sleeve, standard inboard,
carbon adjustable 35mm ? handle with blue grips.

                           My Rigging        Traditional        Innovative
Spread cm             160                    160                     152
Oar Length cm      288                    287                     269.5
Inboard cm           88                      89                       84.5
Outboard cm        200                    198                     185
Overlap cm           22                      20                        20
Blade Length cm   43.5                  43.5                     43.5
Gearing Ratio       2.098               2.050                   2.003

Gearing ratio was derived using inboard Inb and outboard Out in the
equation:

Kleshnevs Formula: G = (Out - SL/2 - SW/2) / (Inb - Hnd/2 + SW/2)

Hnd = handle width (12cm in sculls) = 12cm/2 = 6cm
SW = swivel width = (i.e. thickness, 4cm) = 4cm/2 = 2cm
SL = spoon length = 43.5cm = 43.5cm/2 = 21.75cm
Range = 1.970 - 2.068, Average = 2.004)
(see RBN November 2006)
Overlap for Spread/2 + 8cm = 8cm *2 + 2*SW/2

I must be missing something. By Leverage do you mean Gearing ?Ratios? Are
the Gearing Ratios that far apart? I dont understand how you conclude that
In terms of leverage, your setup would be equivalent to 294.6/160/89.

Cordially,

Charles

 
 
 

Increasing Outboard

Post by James H » Sat, 16 Mar 2013 18:33:15



Quote:
> James,

> Your reply deserves more attention than I giving it. But I am short for
> time, so I thought you might not think too poorly of me if I just give you
> the below link, which I hope you will find interesting.

> http://www.biorow.com/RBN_en_2009_files/2009RowBiomNews01.pdf

> There are many reasons for rowing short. Foir example, Ellen Braithwaite
> described to me one of the times she raced the Catalina Crossing.

> Ellen was in a double with a friend and they had very carefully determined
> how much effort they could sustain over the period of time they would have
> to race. For a crude measurement of this effort they used a SpeedCoach with
> an impeller to get their through-the-water splits. When the water would
> became rough and their splits got worse, they shortened up and raised the
> rates. Then, as they sculled into calmer water, they dropped the rates and
> got longer.

> By the way, this helped me to understand the reasons why through-the-water
> speed is so useful. In Ellen's case over-the-land speed -- i.e. GPS -- would
> have been useless.

> Cordially,

> Charles

Charles

You are quite right - I should not have limited the rowing short to
starts - I often do the sculler's head on the Tideway which has a real
mix of conditions with every turn of the river and twist of the wind.

Water often gets extremely choppy and the standard 'tactic' I was
taught was to hunker down. (weightlift). 2 years ago a much more
experienced sculler than me told me that I should do the opposite - he
said 'brighten it up, keep it sharp and short through those sections.
Which I did, and it kept my splits constant.

Indeed if I am erging and find myself flagging I will often up the
rate from 30 to 32 to 34 to get a relief from the pressure on my legs
and then drop back down (if that is where I am comfortable) to finish
the piece - though I have to say I am trying to sit more comfortably
at the higher rates.

Good to know I am not the only one that likes impeller data - I use an
XL gold and post analyse my race data to see if an increase in rate
brought an increase in speed. There is a trade off where rate and
technique cross over - I rate higher but am just producing froth. The
more I practice the higher this rate becomes - and the more i build
rate work into my warm up routines the better it becomes - especially
as I race in a MX2X most of the season.

I am playing with the reduced spread to improve my catch length (I am
not the most supple of people) and so far 158 seems to suit me -
though the lack of flat water over the last few months means that this
is not as scientific as I would have liked!

James

 
 
 

Increasing Outboard

Post by James H » Sat, 16 Mar 2013 18:37:19



Quote:
> James,

> Your reply deserves more attention than I giving it. But I am short for
> time, so I thought you might not think too poorly of me if I just give you
> the below link, which I hope you will find interesting.

> http://www.biorow.com/RBN_en_2009_files/2009RowBiomNews01.pdf

> There are many reasons for rowing short. Foir example, Ellen Braithwaite
> described to me one of the times she raced the Catalina Crossing.

> Ellen was in a double with a friend and they had very carefully determined
> how much effort they could sustain over the period of time they would have
> to race. For a crude measurement of this effort they used a SpeedCoach with
> an impeller to get their through-the-water splits. When the water would
> became rough and their splits got worse, they shortened up and raised the
> rates. Then, as they sculled into calmer water, they dropped the rates and
> got longer.

> By the way, this helped me to understand the reasons why through-the-water
> speed is so useful. In Ellen's case over-the-land speed -- i.e. GPS -- would
> have been useless.

> Cordially,

> Charles

Stupidly I did not say the one thinking I meant to - which is that I
use a start procedure of 1/2, 1/2, 3/4, 3/4, lengthen over 5 - which
miraculously is exactly what the model proscribes :)

This came about for a lot of reasons, a) it is memorable b) the first
2 strokes are carried out calmly more or less square blade to get the
boat moving, the 3/4 lengthen catches up with the speed of the boat
and by stroke 10 we are into our full length - 5 strokes later we call
'stride' to drop the rate to whatever we have agreed for the race
conditions and settle down to see where our opposition is and what we
should do.

James

 
 
 

Increasing Outboard

Post by johnflo.. » Sat, 16 Mar 2013 23:48:45

Quote:

> >> Here are the numbers that according to Valery Kleshnevs Rowing Speed

> >> and

> >> Rigging Chart are Traditional: 287/160/89.

> >> Here are the numbers for my current rigging: 288/160/87. As you can see

> >> these numbers are nearly identical to Dr. Kleshnevs Traditional numbers.

> >They're not "nearly identical".  Your shorter inboard

> > decreases your leverage and your greater length

> > does the same.  In terms of leverage, your

> > setup would be equivalent to 294.6/160/89.

> > And your shorter inboard will decrease your arc

> > versus his Traditional setup.

> John,

> Obviously I am missing something. You write: in terms of leverage. How are

> you arriving at a measurement for leverage?

> I used a very simple formula for Gearing Ratio. I copied it from Dr.

> Kleshnev.

> My sculls are Croker Oars -- S2 Soft Superlights with Slick blade, 285

> +/-3cm length, zero degree pitch, asymmetric sleeve, standard inboard,

> carbon adjustable 35mm ? handle with blue grips.

>                            My Rigging        Traditional        Innovative

> Spread cm             160                    160                     152

> Oar Length cm      288                    287                     269.5

> Inboard cm           88                      89                       84.5

> Outboard cm        200                    198                     185

> Overlap cm           22                      20                        20

> Blade Length cm   43.5                  43.5                     43.5

> Gearing Ratio       2.098               2.050                   2.003

> Gearing ratio was derived using inboard Inb and outboard Out in the

> equation:

> Kleshnevs Formula: G = (Out - SL/2 - SW/2) / (Inb - Hnd/2 + SW/2)

> Hnd = handle width (12cm in sculls) = 12cm/2 = 6cm

> SW = swivel width = (i.e. thickness, 4cm) = 4cm/2 = 2cm

> SL = spoon length = 43.5cm = 43.5cm/2 = 21.75cm

> Range = 1.970 - 2.068, Average = 2.004)

> (see RBN November 2006)

> Overlap for Spread/2 + 8cm = 8cm *2 + 2*SW/2

> I must be missing something. By Leverage do you mean Gearing ?Ratios? Are

> the Gearing Ratios that far apart? I dont understand how you conclude that

> In terms of leverage, your setup would be equivalent to 294.6/160/89.

Your original post said your inboard was 87cm, in the table above you posted 88cm??

As a crude rule of thumb, changing the inboard 1 cm has roughly the same effect as changing the outboard 2cm, because as you saw with the calculations the outboard is roughly twice the inboard.

Your setup has two changes vs the Traditional, both of which would decrease your leverage:
- inboard 2 (or 1?) cm less
- outboard 3 (or 2? cm less)
(of course not factoring in swivel width and oar blade center of effort)

The ratio calculations are interesting because they show what a narrow range we are rigging within: "innovative" and "traditional" rations are only about 2% apart.  Which also suggests that ratio may not be the best way to emphasize the differences?

It's also interesting that your rigging is about as far from "Traditional" as "Innovative" is, only in the opposite direction.

 
 
 

Increasing Outboard

Post by Charles Carrol » Sun, 17 Mar 2013 02:27:53

Quote:
>Your original post said your inboard was 87cm,
>in the table above you posted 88cm??

John,

My mistake! I was looking at my notes, only I was looking at the wrong day.
The day before I had a lesson with Gordon Hamilton. In an attempt to get
just a little longer at the finish Gordon had suggested decreasing the
inboard by 1 cm. Thus the 87 cm instead of the 88. I went out the next day,
didn t like the new rigging, and immediately reset it to 288/160/88.

Valery Kleshnev s Traditional rigging is 287/160/89. This uses a 9 cm
overlap, which results in an 18 cm handle overlap or a total overlap of 22
cm when the swivel width is added. A total overlap of 22 cm is just too
large for me. It does not allow me to spread the oar handles far enough
apart, so it spoils my finish.

I think your point about the ratio calculations is spot on. They do indeed
show what a narrow range we are rigging within. I also don t know how useful
these ratios are.

It seems to me that it is very easy to change gears in sculling. All you
have to do is change the length of your slide. Shorten up and don t you
scull in a lower gear? Get longer and don t you scull in a higher gear? Isn t
it just that simple?

Notice I did not bother to mention shell velocity. Doesn t an increase in
velocity also change the gearing?

And I have found, too, that it is also easy to change the leverage as easy
as lowering or raising your grip on the oar handles. Take Frank Cunningham s
suggestion that he proper way to grip is oar handle is with the forefingers
resting on the radiused end of the handle and the second joint of the
second finger approximately on top of it. Doesn t this maximize the
leverage?

Now move your grip down the oar handle so that the second joint of the
second finger is 2 cm from the radiused end of the handle. Doesn t this
reduce your leverage and while permitting you to spread the handles just a
bit further apart at the catch?

Years back I took lessons with Christian Dahlke. Christian likes to coach
from a Double. In every lesson we did a drill where we moved our hands off
the grips and down the sculls maybe 20 or more centimeters. It really makes
a gearing change obvious.

But it is fun to play with this stuff, isn t it? It is amazing how for some
of us rigging takes on almost religious connotations

Cordially,

Charles

 
 
 

Increasing Outboard

Post by Charles Carrol » Tue, 19 Mar 2013 09:05:22

Quote:
> I am playing with the reduced spread to improve my catch length (I am
> not the most supple of people) and so far 158 seems to suit me -
> though the lack of flat water over the last few months means that this
> is not as scientific as I would have liked!

James,

As I believe that I may have mentioned I have tried everything I could think
of to increase the time my blades are in the water drive.

1)    I have moved the stretcher sternwards.
2)    I have decreased the spread as far as my riggers allow.
3)    I have decreased the inboard.

As a result I have improved the catch angle, frontloaded the drive, and
succeeded in prolonging the time the blades are in the water during the
drive.

I, however, am not especially happy with these results. Instead of helping
me go faster, they seem to slow me down.

Why?

Valery Kleshnev in the September 2011 RBN writes: Changing oar length in
quite large scale doesnt affect significantly forces, power and boat
speed Shorter oars and lighter gearing allow faster drive and, hence,
higher stroke rate, but decrease blade efficiency.

And then Dr. Kleshnev adds: An optimal gearing is a balance between rowers
and blade efficiencies and depends on rowers dimensions and boat speed.

It is this latter conclusion that really interests me specifically Dr.
Kleshnevs conclusion about blade efficiency.

I have always thought of blade efficiency in terms of how much energy is
wasted shoveling water as opposed to moving the shell.  Efficient blades
move boats, inefficient blades shovel water. In other words, the more
efficient the bladework, the more useful the power produced.

But now I have reservations about this idea. It strikes me that it is
possibly too simple.

Remember Kleshnev? If shorter oars and lighter gearing allow a faster drive
and higher stroke rate, but decrease blade efficiency, then wont longer
oars and heavier gearing slow the drive and lower the stroke rate, but
increase blade efficiency?

I have had just that experience. I had a very efficient blade, but I was
severely over-geared. As a result my handle velocity slowed considerably.
Although I prolonged the time I was able to keep my blades in the water
during the drive, I lost whatever advantage this might have given me because
it took me so long to move my oar handles from catch to finish.

So there is a balance. I am not quite sure I know what it is, but I know it
is there.

Cordially,

Charles