Stampfli scull shape
Zak
Essentially most boats are a fairly similar shape, and this one seems to be
the only major break from tradition. I have also heard the theory behind it,
but am confused that more people don't row it at international level. If
anybody knows of a fault in it's design, or can shed some more light on it,
please post.
Regards
Zak
Fredrik Ludl
Zak <jhb...@iafrica.com> wrote in message
news:82idjt$2bud$1...@nnrp01.ops.uunet.co.za...
Carl Douglas
>I have seen the Stampfli single scull, and am curious about it's shape.
>Essentially most boats are a fairly similar shape, and this one seems to be
>the only major break from tradition. I have also heard the theory behind it,
>but am confused that more people don't row it at international level. If
>anybody knows of a fault in it's design, or can shed some more light on it,
>please post.
>
>Regards
>
>Zak
>
>
Empacher & fisa-hull clones. But the doubles & fours are the same shape
as Janouseks.
Among other singles with markedly different hull forms are van Dusen,
Resolute &, of course, Carl Douglas.
That you don't see more non-clone boats at international level has much
to do with the absolute reluctance of rowers & coaches to depart from
what they know, & not much to do with the actual, measurable, relative
speed potential of the different hull forms - as those of us who *have*
performed exhaustive, on-the-water, comparative speed tests can
certainly confirm.
Most in rowing take a conservative (?insecure) view. Rather than make
the tests to find a faster boat, which requires rigorous measurements of
their relative performances (far too much bother!), many prefer to race
in one no slower than their opposition's. Seeing many boats of one
particular colour, or another, can bring the easy, but not necessarily
warranted, assumption that colour = speed. Yet a review of one well-
known manufacturer's recent advertisements reveals that Gold-medallists
use a wider range of boat-makes than those finishing in lower positions.
I can't resist to make the point here that what applies to boats applies
also, in particular, to rigging. Boats & rigging both interpose drag
between you and the mix of water, spray & wind through which you row.
Boats move as a result of work being done to overcome drag. Reduce drag
& a crew goes faster. There are rigger designs which create
significantly, race-winningly, less drag than others. Now what riggers
would I be talking about there ;^) ?
Cheers -
Carl
Carl Douglas Racing Shells
(for AeRoWing low-drag Riggers & Fine Small-Boats)
The Boathouse, Timsway, Chertsey Lane, Staines TW18 3JZ, Great Britain
URL http://www.rowing-cdrs.demon.co.uk TEL +44 (0) 1784-456344
E-mail carld...@rowing-cdrs.demon.co.uk FAX +44 (0) 1784-466550
AlexFilRep
>known manufacturer's recent advertisements reveals that Gold-medallists
>use a wider range of boat-makes than those finishing in lower positions.
Well said, Carl!
Mmm.. I wonder who that might be? The review also shows that they were very
popular from 4th place downwards..
The bottom line: if you feel comfortable in your boat, don't worry about the
"different" hull shape or color.
The best hull for you is the one YOU feel best in. Try as many as you can.
Alex Selvig , Elite Rowing, Inc.
FILIPPI N. America, Martinoli & Nielsen-Kellerman Products, Boat Transportation
70 Lake Street, Boston, MA USA 02135
Tel & Fax (617) 783-8442
WWW. FILIPPIBOATS.IT
The Best Value in Racing Shells.
Tony Curran
This is a nice sentiment but in practice is very hard to do. Where does
one go to test as many different singles as one can before making an
informed decision about which single to buy.
I look around the boathouse at the Ottawa Rowing Club where I'm located
and see 95% Hudson singles - the others are Kaschper and Vespoli.
So now I must travel to a place where many different boats exist but
where is that. So in central/east Canada, that may be St. Catherines or
maybe somewhere in Toronto. Even if one finds a boathouse with lots of
different types of shells in then you have to gain permission from owner
to lend a boat to a total stranger. Its not going to happen.
So I throw down the gauntlet to all you singles manufacturers and
salesman out there:
Get your collective selves together and maybe do a "roadshow" and take
your wares to major rowing centres and invite joe rowing/sculling public
to tryout your offerings. Have hwt, not-so-hwt, mid-wt, lwt and bantom
wt boats available. Only then can one make fair judgements.
Just over a year ago I took charge of a Carl Douglas CD-X 92kg. Why did
I pick that boat? I'd never rowed one before. Carl has been the only
boat manufacturer active on the r.s.r that explained his decisions
behind the design of his shell/riggers. I don't follow the pack. It fit
my racing weight. It fit in my price bracket. The exchange rate was
right. And it wasn't a wing rigger (very important). I'm also English
and I know of his reputation in th UK.
So, com'on you boatbuilders, are you up to the challenge?
Tony
Ottawa RC
Carl Douglas
>>a review of one well-
>>known manufacturer's recent advertisements reveals that Gold-medallists
>>use a wider range of boat-makes than those finishing in lower positions.
>
>Well said, Carl!
>
>Mmm.. I wonder who that might be? The review also shows that they were very
>popular from 4th place downwards..
>
>The bottom line: if you feel comfortable in your boat, don't worry about the
>"different" hull shape or color.
>
>The best hull for you is the one YOU feel best in. Try as many as you can.
>
Comfort is important but, hitherto, the evolution of faster boats has
led to shells which are harder to row but better repay the effort of
mastering them. Should we now forget all about design improvements &
concentrate solely on comfort, comfort & comfort? Will the Sydney
finals be raced in armchairs?
The history of rowing repeatedly shows how comfort is sacrificed for
speed. Faster boats have demanded, & will in future demand, different &
greater skills to realise their speed potentials. That's life, but it's
fun.
G. Nolin
the aerodynamic rigger that you are referring to is obviously the carbon
wing rigger available from Pocock Racing Shells. it is the most
aerodynamic outrigger available and much, much stiffer than any, including
any aforementioned standard side bolt-on rigger, available today, in any
country.
g
> warranted, assumption that colour = speed. Yet a review of one well-
> known manufacturer's recent advertisements reveals that Gold-medallists
> use a wider range of boat-makes than those finishing in lower positions.
>
> I can't resist to make the point here that what applies to boats applies
> also, in particular, to rigging. Boats & rigging both interpose drag
> between you and the mix of water, spray & wind through which you row.
> Boats move as a result of work being done to overcome drag. Reduce drag
> & a crew goes faster. There are rigger designs which create
> significantly, race-winningly, less drag than others. Now what riggers
> would I be talking about there ;^) ?
>
ISSE Toyohi
That is so-called bananna shaped single scull I think.
You can ask and read at the stampli site http://www.janousek.co.uk/ .
This is first time letter for this news group.
Toyohi
LongboatCo
used by several other manufacturers. The X1 has the much "pointy-er" bow and
stern sections, with the most mass appearing just behind the foot stretchers.
I've had the opportunity to row both, although not using any speed/timing
equipment. My experience with the X1 is that it felt very quick on flat water,
but a bit too bouncy on chop, especially with a head wind. The bow had a
tendency to ride on top of the chop, rather than cut through it. Thus I felt a
"wobbly" (US translation!) sensation as the bow bounced over the waves. Given
that races on truly flat water are few and far between, I opted for the S1
hull. At St. Catherines, I noticed that the few Stampfli singles were all
X1's.
As for testing out different boats before buying - I'm all for it if its
logistically possible, and I think most manufacturers would be willing to
accomodate. But having different hulls available that reflect a builders
latest technology represents a sizeable investment in an industry where not too
many of us are getting rich.
As for oars, which are considerably less expensive, I have several pair that I
loan out for extended periods to individuals and clubs just so they can make an
informed comparison. Sometimes they buy, sometimes not; but at least I have
the satisfaction of knowing they gave me, and the oars, a fair chance.
George
The Longboat Company
www.LongboatCo.com
Braca Sport Oars and Sculls
Zak
1996 (Strathclyde), and would love to buy one. Unfortunately, no matter how
well you punt it, I live in South Africa, and the exchange rate would kill
me. Believe me, I looked. Anyway, the reason I need to know is because there
is a local boat builder (who also builds beautiful boats) who is making a
scull of that shape, and I want to buy one. However, I don't want to buy a
boat that will make me slower. The idea is really good, or at least sounds
good, but you understand my concern in that before I lay out a not
insubstantial amount of money, I need to be sure it is quick.
Carl Douglas
>
>the aerodynamic rigger that you are referring to is obviously the carbon
>wing rigger available from Pocock Racing Shells. it is the most
>aerodynamic outrigger available and much, much stiffer than any, including
>any aforementioned standard side bolt-on rigger, available today, in any
>country.
>
>> I can't resist to make the point here that what applies to boats applies
>> also, in particular, to rigging. Boats & rigging both interpose drag
>> between you and the mix of water, spray & wind through which you row.
>> Boats move as a result of work being done to overcome drag. Reduce drag
>> & a crew goes faster. There are rigger designs which create
>> significantly, race-winningly, less drag than others. Now what riggers
>> would I be talking about there ;^) ?
>>
I greatly respect our friends Pocock's products, but I might not agree
with everything you say.
I wonder how you reached your rather categorical conclusions? I try
*never* to presume to know another man's mind & *never* to judge a
product that I have not had full opportunity to evaluate. Now if you
would provide me with your comparative data, then we could
discuss......?
I would also note that wing riggers are normally very specific to the
construction of the boat & few of them offer the possibility for
accurate & unslippable pin pitch adjustment. Meanwhile the vast
majority of existing & new boats use conventional rigging.
In providing optimised bolt-on riggers we confront and try to meet the
very real needs of almost every rower out there and to give them
advantages they didn't have before. Our users seem fairly pleased with
what we do, how we serve them, & how much better our AeRoWing riggers
perform (in every respect) than the alternatives. But we are always
listening.
G. Nolin
any of their standard riggers, which are some of the most adjustable on
the market. nothing slips, for and aft, inboard/outboard, all works
great. as far as the stiffness comment, i think one of the most telling
tests for stiffness, which i am aure will not be scientific enough for you
however, but is to just hold on to the gunwhale and the rigger at the pin
and try to bend it for and aft. every rigger bends this way, and even
more torsionally, but the pocock does not.
my $0.02
g
Nick Suess
> wing rigger available from Pocock Racing Shells. it is the most
> aerodynamic outrigger available
For "available", read instead "made in the USA". Or maybe "made in the
English-speaking world".
Those possessing a thirst for knowledge, check out, s'il vous plaît, des
portants en ailes très aérodynamiques du MPS Composites, pictured on their
website at http://perso.wanadoo.fr/mps.composites/ .
It is written in French, but the pictures translate fairly well.
N
Carel Rijnders
>Yes, the Stampfli single is a "different" shape from the multitude of
>Empacher & fisa-hull clones. But the doubles & fours are the same shape
>as Janouseks.
>
>Among other singles with markedly different hull forms are van Dusen,
>Resolute &, of course, Carl Douglas.
>
>That you don't see more non-clone boats at international level has much
>to do with the absolute reluctance of rowers & coaches to depart from
>what they know, & not much to do with the actual, measurable, relative
>speed potential of the different hull forms - as those of us who *have*
>performed exhaustive, on-the-water, comparative speed tests can
>certainly confirm.
>
>Most in rowing take a conservative (?insecure) view. Rather than make
>the tests to find a faster boat, which requires rigorous measurements of
>their relative performances (far too much bother!), many prefer to race
>in one no slower than their opposition's. Seeing many boats of one
>particular colour, or another, can bring the easy, but not necessarily
>warranted, assumption that colour = speed. Yet a review of one well-
>known manufacturer's recent advertisements reveals that Gold-medallists
>use a wider range of boat-makes than those finishing in lower positions.
>
>also, in particular, to rigging. Boats & rigging both interpose drag
>between you and the mix of water, spray & wind through which you row.
>Boats move as a result of work being done to overcome drag. Reduce drag
>& a crew goes faster. There are rigger designs which create
>significantly, race-winningly, less drag than others. Now what riggers
>would I be talking about there ;^) ?
>
>Carl
Well Carl,
So how good is the Carl Douglas drag factor then? Please share this with us.
I suppose you have tested your hull against all the "others", In different
weather, headwind, tailwind and not to forget wind from the side, different
weights, at the catch, half way through the stroke, at the end of the
stroke.So where are the graphs? And sorry, but I am a bit of a sceptic if
the tests were done by your good selves and proved the Carl Douglas hull to
be the best. I am afraid that only test results from an independent
organisation will get me across. And your even telling us that you have
tested the (wind) drag factor of the Aerowing riggers..............against
all the others??? Well Carl, lets have it, where are the results?
Sorry Carl, you normally make a lot of sense, this one was way off!!
Greetings
Carel
Carl Douglas
>Carl Douglas wrote in message ...
Carel, as always I will try to give a proper answer to your pointed
points. But if only the results of an independent organisation will
"get you across", then you are not going to be convinced, either by me,
or by anyone else.
Perhaps, if you really are open to being convinced, & since you have
already ruled out any tests made by ourselves & our clients, or any drag
calculations that we or others may have made, you should state which
tests you would think meaningful, & why. I'd then, quite genuinely, be
very pleased to discuss with you how they might be performed & their
likely relevance to actual racing performance?
I'd also like to know which other racing shell builders you have asked &
who would, or already have responded, at this level to your challenge?
Clearly we must exclude the cloners, which narrows down the field quite
spectacularly. And of the others? None, I think :-)
So let's address a few of the issues:
To hire a sufficiently-deep & wide testing tank for a half-reasonable
series of comparative, constant-velocity tests in still water/still air
for, say, just 3 different hulls, when I last enquired quite a few years
ago, would have set us back about GBP20,000 (say US$33,000). And that
was before doing either the preparation or the post-test analysis.
Yet those results would have been largely meaningless, even if we ignore
the issue of wind & waves, because they'd have excluded such matters as
a racing shell's oscillating velocity & pitch, & its response to
different rowing techniques. And they would have been for only one boat
class. Would the boats have been identically rigged, or would they have
been equipped "as original". What about the effect of rower physique on
the overall aerodynamics of different boats. Would/could the tests have
located the C of G suitably (beyond subsequent dispute) - especially
since it is always on the move. And many more.
So how much to explore all of these possibilities in a tank test, even
for one hull design, let alone 3, let alone different displacements,
etc.?
Or you could attack the problem using Computational Fluid Dynamics
procedures? Would you believe the results? CFD is used in many fields
of vehicle design (though frequently in harness with wind-tunnel tests,
etc.), but I know of none (I'm very much open to correction) which is
validated (i.e. compared successfully with real life) for the
particularly interesting problem of ultra-light-displacement surface
vessels running at high Froude-number with pulsed-velocity & pitch -
involving a fluid interface with significant drag induced in both
fluids. I've discussed CFD analysis with more than one company in the
field: the costs would frighten anyone intending to remain in business
while the promised outcomes were far from promising. Indeed, I recall
one such service provider suggesting that, while the results might not
mean much, the graphics would be very useful for promotional purposes -
which, if you know us, is *not* how we do business.
I'd suggest that such supposedly-objective tests tell you rather little
about real life.
As on many previous occasions on RSR, I would argue that the only truly
meaningful tests are those conducted by real rowers on real water but
under proper test conditions (successful use by real rowers is, after
all, the objective). This takes a number of forms, among which (the
list is not exhaustive) consider:-
1. To compare boats:
a) On-the-water Testing: In stable conditions of wind & water, on a
measured stretch of, say 500m, rig equivalently (dimensionally & in the
rower's minds) 2 or more different makes of boat of the same nominal
crew weight. Time the crew repeatedly covering the measured distance at
race pressure in each boat in succession, with equal time breaks between
pieces, varying the order in which the boats are used. Obtain at least
4 timings in each boat, but preferably more. Plot your crew's results
as time taken vs piece number. We have done this several times, & we
like the results. I wouldn't myself reject a 3 to 5 sec/1k advantage
over the nearest opposition, singles or doubles.
This will, if crew performance is consistent & tests were properly
conducted, give you a set of separated lines showing a clear speed
order. Preferably the tests should be repeated on a second day for
comparison, & no more than 3 boats should be included within a test
series. Preferably repeat these tests with other crews.
b) Race comparisons: Compare the performance gain (hopefully!) as
reported by users & as demonstrated by their results, following changing
to a Carl Douglas shell.
2. To compare riggers:
a) Direct measurement: Mount a pair of riggers made for the same
specification but different sides (in our case 1 AeRoWing & 1 of various
other designs) on a simulated pair of saxboards with a central pivot on
a windy day. Measure the moment required to keep this pair of riggers
in the head-to-wind alignment and which rigger it favours. It will
normally favour AeRowing.
b) Positive feedback: Listen to your clients' reactions to having retro-
fitted AeRoWing riggers to their boats, such as "no-longer getting water
into the boat when the water's rough", "feels far more positive", "I
can now beat so-&-so who I couldn't beat before". Listen also for
adverse comments, & if none, you may count that in your favour.
c) Negative feedback: Here I count the following sort of comment "Into a
headwind I can easily beat so-&-so who has X's multi-stay riggers but
with a tailwind we are of equal speed". Now we calculate that into a
5m/sec headwind AeRoWing scull riggers yield a 2 to 2.5sec/2k advantage
for a 1x over 4-stay riggers &, when we check on the relevant wind
speeds, we find that on average they are consistent with that
differential.
d) Calculation: Fluid drag is calculable as A*Cd*rho*v^2*k/(2*g), where
A is frontal area, Cd is drag coefficient of that geometrical section
(these are well-tabulated for all kinds of foil & tubular section, rho
is fluid (air) density, v is velocity, k is a factor (l or larger) for
interference (2 or more tubes in close proximity across the flow create
additional resistance due to part of the flow funnelling through the
gap) & g is acceleration due to gravity. Go do the sums, which is what
we did in designing the riggers!
Of course, I can't compel Carel to believe me. There is always a deal
of honest disbelief, besides the usual welter of prejudice masquerading
as expertise. But I believe it is right to ask rowers to use their
heads, rather than swallow that unexplained, anti-intellectual &
insupportable kind of shouted publicity easiest summed up as the '
"We're fastest" No you're not; *we're* fastest" ' school of
advertising. I have always preferred to show that rowing & its
equipment is susceptible to scientific & technical analysis. It is
largely in the cause of better understanding & the eradication of
bullshit that I try to explain on RSR, in terms comprehensible to lay
persons, the phenomena which govern the propulsion, & the drag
resistance, of racing shells.
Despite the impossibility of giving him the only answers which, he has
said, he would believe, I hope I can still exclude Carel from that group
which buys only products promoted with pseudo-science & the brown stuff?
Or should I have saved myself a lot of time & trouble, instead
trumpeting the fact that, despite the blind support for products of a
certain colour or shape, of the around 100 of our shells in his country
(Holland) there are a heck of a lot of highly successful & long-lasting
examples, every one of which was paid for by their owner.
Cheers, & as many wins as you wish yourselves in 2000!
Carl Douglas
<row...@rowing-cdrs.demon.co.uk> writes<snipped>
Oops!
Large chunk of my reply snipped so that I could correct the following
typo:
>I wouldn't myself reject a 3 to 5 sec/1k advantage
>over the nearest opposition, singles or doubles.
"I wouldn't myself reject a 3 to 5 sec/2k advantage over the nearest
opposition......."
I didn't want you to get too excited, folks!
Cheers -
Leo Lazauskas
"Zak" <jhb...@iafrica.com> wrote:
> ...but you understand my concern in that before I lay out a not
> insubstantial amount of money, I need to be sure it is quick.
> >
> >Resolute &, of course, Carl Douglas.
> >
How long are you prepared to wait before buying, Zak?
A new series of hulls will be released in the US in a couple of months.
The drag curves for the Singles will be somewhere between the "King
hulls" and the GODZILLA hulls on my WWW rowing pages. I'll put up the
actual curves for comparisons as soon as the molds are ready. I now
also have the lines for the Resolute and some other commercially-
available hulls: I'll try to include them too.
http://www.maths.adelaide.edu.au/Applied/llazausk/leo.htm
Look in Hydro/Rowing.
Of course, the best hull for you is one that is tailor-made to suit
your particular expected "rowing environment" and your personal rowing
style. But to get that customisation, you need to consult someone who
can take all those factors into account and who can then build those
features into a hull. There aren't many individuals or firms that can
do that, and the cost would be higher than for an off-the-shelf hull. I
suppose it's simply a matter of "you pays your money and you take your
choices".
Good luck with your search,
Leo.
Sent via Deja.com http://www.deja.com/
Before you buy.