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Oxford University Boatman discusses wing riggers
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Stelph
Feb 1, 2012, 5:35:49 AM2/1/12
to
Saw this today and I thought the comments made deserved dissection by
the rec.sport.rowing heavies.
The whole video is quite interesting, but it was the boatmans
description and discussion on wing riggers that stood out:
http://youtu.be/tgsjpyrkRWk?t=1m25s
the rec.sport.rowing heavies.
The whole video is quite interesting, but it was the boatmans
description and discussion on wing riggers that stood out:
http://youtu.be/tgsjpyrkRWk?t=1m25s
sully
Feb 1, 2012, 12:35:09 PM2/1/12
to
(paraphrased)
"you see really irritating little gits turn into quite charming young
mature men".
Carl
Feb 2, 2012, 7:40:22 AM2/2/12
to
The opening wrench-handle-&-Tupperware demo unaccountably forgot that
conventionally rigged shells have rigger shoulders. Why?
Rigger shoulders easily resist the (small) vertical loads applied at the
end of the rigger (we don't row vertically!) & they distribute them
down, through & across the whole cross-section of the hull, not just
onto local points at the top of the saxboards. Thereby they also brace
& stiffen the hull. There's quite a difference in torsional & bending
stiffness between a trough braced by stays spanning its outer edges at
intervals & one with full structural bulkheads at the same intervals (if
in doubt, take an open shoe-box & see what happens as you cut out
material from one end or both).
Simplistic demos are not as smart as they seem.
Not only are the vertical loads on riggers quite small, but they are
trivial when compared with the pulling loads. It is plain daft to claim
that energy is being lost through elastic vertical movement when no
friction is involved. Furthermore, there is no more vertical movement
in a conventional rigger mounted on a well-built shell than in a wing,
while the poor torsional & flexural coupling between boat & wing on most
shells allows significantly greater vertical movement of the ends of
many wing riggers.
But suppose that rigger flexing really did cause energy loss? Why then
would anyone in their right mind use a long single stay, acting as a
cantilever, to resist the main pulling loads? Inevitably it must flex
towards the bow at each stroke. Surely they should demand a properly
triangulated 2-stay rigger?
Not only is the scientific content of their argument defective, but they
have to bend around every obstacle of solid logic. Ho hum.
But suppose they were right? Don't oars flex a vastly more than any
rigger? So why would these "experts" let anyone to race with oars which
bend - not slightly but by really large amounts. Surely that must thus
be throwing away huge amounts of their rowers' output?
Pure tosh, I'm afraid.
BTW, the "F1" word was casually dropped into the video by the former
composites buyer of the transient Super Aguri F1 Team. Of itself that
word makes no more difference, in this context, than an anti-wrinkle
cream with a faux-scientific title makes to a woman's age.
It will serve the sport best if those involved its technicalities hold
to scientific integrity & eschew bullshine. Sadly, the wider public
have a diminishing appreciation of the essential difference.
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)
Stelph
Feb 2, 2012, 8:39:44 AM2/2/12
to
> URLs: www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)
Hi Carl,
Good to see your response, I admit part of why I posted it was the
"simple" explanation the boatman gave bothered me somewhat but I
couldnt put my finger on exactly why, and your post highlights the
points, maininly (and I apologise for over simplifying your points and
if i mis-intreprited any!)
- The example given ignores the difference between wing rigged boats
with no shoulder and boats with conventional rig with shoulders
- The single stay of a wing rigger would not be as resitant to
vertical flex (up and down) and horizontal flex (towards the bows as
you drive through the stroke) as a concentional 3 stay rigger
One thing in the video though that does make sense to me however is
the idea of how the wing rigger goes across the bulkheads as a kind of
brace, as to my mind (and correct me if i am wrong) a cross bar like
that would give additional stiffness.
Therefore it makes sense to me that the ideal/stiffest rigger then
(taking only stiffness into account) is a "conventional" 3 stay rigger
with shoulders, and for additional stiffness additional cross bars
across from bowside to strokeside (like in the photo below). These
could be at the most sternward mounted point of the rigger and at the
backstay points. Ideally it'd also be braced in the middle between the
pins but that might get in the way of the rower.
http://www.google.co.uk/imgres?q=single+scull+cockpit&um=1&hl=en&biw=1160&bih=670&tbm=isch&tbnid=540GQGz7o7cvgM:&imgrefurl=http://minnesotafugue.blogspot.com/&docid=4jwuOypCvppZ3M&imgurl=http://4.bp.blogspot.com/_m-PbOge-cCM/THaApK2nq9I/AAAAAAAAAHo/0deN34pVbok/s1600/boat%252Brefurbished%252B1.JPG&w=1600&h=1200&ei=3ZEqT8KrBIzz-ga58MixDg&zoom=1&iact=hc&vpx=115&vpy=353&dur=687&hovh=194&hovw=259&tx=140&ty=97&sig=118139767439105173923&page=2&tbnh=151&tbnw=213&start=15&ndsp=21&ved=1t:429,r:16,s:15
(this obviously ignores any wind resistnace from having 3-stay riggers
etc and just focuses on what the stiffest rigger set up would be)
Does that make sense?
Kit
Feb 2, 2012, 9:19:29 AM2/2/12
to
On Feb 2, 1:39 pm, Stelph <thomas.k.car...@googlemail.com> wrote:
> Therefore it makes sense to me that the ideal/stiffest rigger then
> (taking only stiffness into account) is a "conventional" 3 stay rigger
> with shoulders, and for additional stiffness additional cross bars
> across from bowside to strokeside (like in the photo below). These
> could be at the most sternward mounted point of the rigger and at the
> backstay points. Ideally it'd also be braced in the middle between the
> pins but that might get in the way of the rower.
>
LOL. I learnt to row in a boat like that. Needless to say, skying was
> Therefore it makes sense to me that the ideal/stiffest rigger then
> (taking only stiffness into account) is a "conventional" 3 stay rigger
> with shoulders, and for additional stiffness additional cross bars
> across from bowside to strokeside (like in the photo below). These
> could be at the most sternward mounted point of the rigger and at the
> backstay points. Ideally it'd also be braced in the middle between the
> pins but that might get in the way of the rower.
>
never much of a problem.
IPS
Feb 3, 2012, 1:11:09 AM2/3/12
to
>
> (this obviously ignores any wind resistnace from having 3-stay riggers
> etc and just focuses on what the stiffest rigger set up would be)
>
> Does that make sense?
That's exactly how the old wooden Donoraticos were built - and I still
> (this obviously ignores any wind resistnace from having 3-stay riggers
> etc and just focuses on what the stiffest rigger set up would be)
>
> Does that make sense?
have the scars on the backs of my fingers from bashing my hands into
that damned cross bar!
sully
Feb 3, 2012, 2:45:11 PM2/3/12
to
Carl
Feb 5, 2012, 8:05:28 AM2/5/12
to
On 02/02/2012 13:39, Stelph wrote:
> On Feb 2, 12:40 pm, Carl<s...@sss.jjj> wrote:
>> On 01/02/2012 10:35, Stelph wrote:
>>
>>> Saw this today and I thought the comments made deserved dissection by
>>> the rec.sport.rowing heavies.
>>
>>> The whole video is quite interesting, but it was the boatmans
>>> description and discussion on wing riggers that stood out:
>>
>>> http://youtu.be/tgsjpyrkRWk?t=1m25s
>>
>> Thank you :)
>>
>> The opening wrench-handle-&-Tupperware demo unaccountably forgot that
>> conventionally rigged shells have rigger shoulders. Why?
>>
>> Rigger shoulders easily resist the (small) vertical loads applied at the
>> end of the rigger (we don't row vertically!)& they distribute them
>> down, through& across the whole cross-section of the hull, not just
> On Feb 2, 12:40 pm, Carl<s...@sss.jjj> wrote:
>> On 01/02/2012 10:35, Stelph wrote:
>>
>>> Saw this today and I thought the comments made deserved dissection by
>>> the rec.sport.rowing heavies.
>>
>>> The whole video is quite interesting, but it was the boatmans
>>> description and discussion on wing riggers that stood out:
>>
>>> http://youtu.be/tgsjpyrkRWk?t=1m25s
>>
>> Thank you :)
>>
>> The opening wrench-handle-&-Tupperware demo unaccountably forgot that
>> conventionally rigged shells have rigger shoulders. Why?
>>
>> Rigger shoulders easily resist the (small) vertical loads applied at the
>> end of the rigger (we don't row vertically!)& they distribute them
>> onto local points at the top of the saxboards. Thereby they also brace
>> & stiffen the hull. There's quite a difference in torsional& bending
>> stiffness between a trough braced by stays spanning its outer edges at
>> intervals& one with full structural bulkheads at the same intervals (if
>> in doubt, take an open shoe-box& see what happens as you cut out
>> material from one end or both).
>>
>> Simplistic demos are not as smart as they seem.
>>
>> Not only are the vertical loads on riggers quite small, but they are
>> trivial when compared with the pulling loads. It is plain daft to claim
>> that energy is being lost through elastic vertical movement when no
>> friction is involved. Furthermore, there is no more vertical movement
>> in a conventional rigger mounted on a well-built shell than in a wing,
>> while the poor torsional& flexural coupling between boat& wing on most
>>
>> Simplistic demos are not as smart as they seem.
>>
>> Not only are the vertical loads on riggers quite small, but they are
>> trivial when compared with the pulling loads. It is plain daft to claim
>> that energy is being lost through elastic vertical movement when no
>> friction is involved. Furthermore, there is no more vertical movement
>> in a conventional rigger mounted on a well-built shell than in a wing,
>> shells allows significantly greater vertical movement of the ends of
>> many wing riggers.
>>
>> But suppose that rigger flexing really did cause energy loss? Why then
>> would anyone in their right mind use a long single stay, acting as a
>> cantilever, to resist the main pulling loads? Inevitably it must flex
>> towards the bow at each stroke. Surely they should demand a properly
>> triangulated 2-stay rigger?
>>
>> Not only is the scientific content of their argument defective, but they
>> have to bend around every obstacle of solid logic. Ho hum.
>>
>> But suppose they were right? Don't oars flex a vastly more than any
>> rigger? So why would these "experts" let anyone to race with oars which
>> bend - not slightly but by really large amounts. Surely that must thus
>> be throwing away huge amounts of their rowers' output?
>>
>> Pure tosh, I'm afraid.
>>
>> BTW, the "F1" word was casually dropped into the video by the former
>> composites buyer of the transient Super Aguri F1 Team. Of itself that
>> word makes no more difference, in this context, than an anti-wrinkle
>> cream with a faux-scientific title makes to a woman's age.
>>
>> It will serve the sport best if those involved its technicalities hold
>> to scientific integrity& eschew bullshine. Sadly, the wider public
>> many wing riggers.
>>
>> But suppose that rigger flexing really did cause energy loss? Why then
>> would anyone in their right mind use a long single stay, acting as a
>> cantilever, to resist the main pulling loads? Inevitably it must flex
>> towards the bow at each stroke. Surely they should demand a properly
>> triangulated 2-stay rigger?
>>
>> Not only is the scientific content of their argument defective, but they
>> have to bend around every obstacle of solid logic. Ho hum.
>>
>> But suppose they were right? Don't oars flex a vastly more than any
>> rigger? So why would these "experts" let anyone to race with oars which
>> bend - not slightly but by really large amounts. Surely that must thus
>> be throwing away huge amounts of their rowers' output?
>>
>> Pure tosh, I'm afraid.
>>
>> BTW, the "F1" word was casually dropped into the video by the former
>> composites buyer of the transient Super Aguri F1 Team. Of itself that
>> word makes no more difference, in this context, than an anti-wrinkle
>> cream with a faux-scientific title makes to a woman's age.
>>
>> It will serve the sport best if those involved its technicalities hold
understand. We're born to question: as soon as they learn to talk
bright kids start asking "Why?" about all they see & hear. Only by
questioning do we truly learn. After far too many years, I'm still
questioning, all the time. Finding better (= more rational) answers to
questions still causes me to revise some of my views. When we can learn
no more, it's time to die.
Blinkers are for cart-horses, to stop them seeing the truth, & are
inappropriate accessories for intelligent folk. Those who spout
unquestioningly the comforting garbage heard in that video deliberately
mislead most of their audience & expose their own blinkered ignorance.
I trust that for RSR we have buried the notion that small amounts of
vertical flexure waste energy & make boats slower? But that video will
remain out there & still be swallowed as gospel by many rowers.
All structures, even mountains, flex under applied load & slight flexing
is often irrelevant, but in some cases rigidity _is_ critical. If a
rigger moves very slightly in the vertical plane that's probably
unimportant, but if a boat either twists a bit more, or takes on more
water in use, that matters a lot.
Not to your questions:
A strut across the top of a boat will enhance its stiffness, but didn't
I give you that shoebox example?
In an eight - essentially a long, open U-section channel with somewhat
flexible edges - you can add some stiffness by putting struts across it
but it is more effective to fit vertical bulkheads which continue up to
the tops of the saxboards & provide proper shear connection right around
the hull at that point - as the shoe-box example tells you.
On rigger stiffness, the point where flexure matters most is inside the
boat. Taking a sculling boat: local flexing near the end of the rigger
matters rather little, but deflection within the structure in the middle
of the boat (whether the centre of a wing or in the middle of the main
shoulder of a conventionally rigged boat) greatly affects the amount the
rigger end moves.
In your picture link the weakest, most flexible part of that venerable
1x is not the riggers but the main shoulder. It was popularly but
wrongly believed that the main shoulder was already adequate, or
couldn't be made stiffer. But the vertical bending moment within the
entire rigger structure is greatest at the boat's centreline, where a
mere 1 degree of flex on either side at that line will cause nearly 15mm
(5/8") of vertical movement at the end of each rigger!
In contrast, at 1/2 way between the centre of the boat & the pin the
bending moment is only 1/2 of that at the boat's centreline _&_ a local
flexure of 1/2 degree there will only move the rigger end by less than
4mm (say 1/8"). This inverse relationship between distance from the
centre & local degree of flexure applies to any cantilever with a
bending load applied only at its end. In simple cantilevers it
encourage an exponentially tapering shape with the beef concentrated
where you have the highest bending moment. With relevant adjustments
for variable wind force it explains the form of such structures as the
Eiffel Tower. (Torsional & cost considerations in riggers will change
that somewhat.)
So, if you want the least vertical movement, stiffening the point(s) of
attachment of the rigger structure & where the bending moment will be
greatest. With conventional riggers make the main shoulder
appropriately stiff (so easily done!); for wing riggers pay particular
attention to the stiffness (& strength) of the often poorly reinforced
saxboards. When wing riggers first appeared there was a lot of silly
talk about being able to dispense with rigger shoulders, followed by a
lot of premature failures of rigger mountings & saxboards & a great deal
of vertical movement of rigger ends (due to the conversion of vertical
loads at the pins into torsional stresses over the rather short
footprint where the rigger attaches to the saxboards).
Wing riggers are often not good at handling the torsional loadings of
rowing, or you would not see topstays/backstays on all sweep riggers.
As indicated above, part of this problem is not with the rigger, per se,
but with is attachment to the boat.
So, by good engineering which properly understands the stresses within
the rigger/boat system a number of workable solutions are available.
The triangulation of a 2-stay, side-mounted rigger gives you a rigger
structure which is extremely stiff in the pulling direction & very stiff
in torsion & vertical flexure. With the long-term stiffening &
reinforcing of the hull from the presence of regular &
properly-connected internal shoulder/bulkhead structures this option
gives you a win-win situation.
But I would encourage doubt & accordingly, unlike shallower pundits, I'm
very happy to answer further questions on this.
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
Carl
Feb 7, 2012, 6:51:14 AM2/7/12
to
On 03/02/2012 19:45, sully wrote:
> On Feb 2, 10:11 pm, IPS<roco...@gmail.com> wrote:
>> On Feb 2, 5:39 am, Stelph<thomas.k.car...@googlemail.com> wrote:
>>> On Feb 2, 12:40 pm, Carl<s...@sss.jjj> wrote:
>>>> On 01/02/2012 10:35, Stelph wrote:
>>
>>>>> Saw this today and I thought the comments made deserved dissection by
>>>>> the rec.sport.rowing heavies.
>>
>>>>> The whole video is quite interesting, but it was the boatmans
>>>>> description and discussion on wing riggers that stood out:
>>
>>>>> http://youtu.be/tgsjpyrkRWk?t=1m25s
>>
>>>> Thank you :)
>>
>>>> The opening wrench-handle-&-Tupperware demo unaccountably forgot that
>>>> conventionally rigged shells have rigger shoulders. Why?
>>
>>>> Rigger shoulders easily resist the (small) vertical loads applied at the
> On Feb 2, 10:11 pm, IPS<roco...@gmail.com> wrote:
>> On Feb 2, 5:39 am, Stelph<thomas.k.car...@googlemail.com> wrote:
>>> On Feb 2, 12:40 pm, Carl<s...@sss.jjj> wrote:
>>>> On 01/02/2012 10:35, Stelph wrote:
>>
>>>>> Saw this today and I thought the comments made deserved dissection by
>>>>> the rec.sport.rowing heavies.
>>
>>>>> The whole video is quite interesting, but it was the boatmans
>>>>> description and discussion on wing riggers that stood out:
>>
>>>>> http://youtu.be/tgsjpyrkRWk?t=1m25s
>>
>>>> Thank you :)
>>
>>>> The opening wrench-handle-&-Tupperware demo unaccountably forgot that
>>>> conventionally rigged shells have rigger shoulders. Why?
>>
>>>> Rigger shoulders easily resist the (small) vertical loads applied at the
>>>> end of the rigger (we don't row vertically!)& they distribute them
>>>> down, through& across the whole cross-section of the hull, not just
>>>> onto local points at the top of the saxboards. Thereby they also brace
>>>> & stiffen the hull. There's quite a difference in torsional& bending
>>>> stiffness between a trough braced by stays spanning its outer edges at
>>>> intervals& one with full structural bulkheads at the same intervals (if
>>>> in doubt, take an open shoe-box& see what happens as you cut out
>>>> material from one end or both).
>>
>>>> Simplistic demos are not as smart as they seem.
>>
>>>> Not only are the vertical loads on riggers quite small, but they are
>>>> trivial when compared with the pulling loads. It is plain daft to claim
>>>> that energy is being lost through elastic vertical movement when no
>>>> friction is involved. Furthermore, there is no more vertical movement
>>>> in a conventional rigger mounted on a well-built shell than in a wing,
>>>> while the poor torsional& flexural coupling between boat& wing on most
>>
>>>> Simplistic demos are not as smart as they seem.
>>
>>>> Not only are the vertical loads on riggers quite small, but they are
>>>> trivial when compared with the pulling loads. It is plain daft to claim
>>>> that energy is being lost through elastic vertical movement when no
>>>> friction is involved. Furthermore, there is no more vertical movement
>>>> in a conventional rigger mounted on a well-built shell than in a wing,
>>>> shells allows significantly greater vertical movement of the ends of
>>>> many wing riggers.
>>
>>>> But suppose that rigger flexing really did cause energy loss? Why then
>>>> would anyone in their right mind use a long single stay, acting as a
>>>> cantilever, to resist the main pulling loads? Inevitably it must flex
>>>> towards the bow at each stroke. Surely they should demand a properly
>>>> triangulated 2-stay rigger?
>>
>>>> Not only is the scientific content of their argument defective, but they
>>>> have to bend around every obstacle of solid logic. Ho hum.
>>
>>>> But suppose they were right? Don't oars flex a vastly more than any
>>>> rigger? So why would these "experts" let anyone to race with oars which
>>>> bend - not slightly but by really large amounts. Surely that must thus
>>>> be throwing away huge amounts of their rowers' output?
>>
>>>> Pure tosh, I'm afraid.
>>
>>>> BTW, the "F1" word was casually dropped into the video by the former
>>>> composites buyer of the transient Super Aguri F1 Team. Of itself that
>>>> word makes no more difference, in this context, than an anti-wrinkle
>>>> cream with a faux-scientific title makes to a woman's age.
>>
>>>> It will serve the sport best if those involved its technicalities hold
>>>> to scientific integrity& eschew bullshine. Sadly, the wider public
>>>> many wing riggers.
>>
>>>> But suppose that rigger flexing really did cause energy loss? Why then
>>>> would anyone in their right mind use a long single stay, acting as a
>>>> cantilever, to resist the main pulling loads? Inevitably it must flex
>>>> towards the bow at each stroke. Surely they should demand a properly
>>>> triangulated 2-stay rigger?
>>
>>>> Not only is the scientific content of their argument defective, but they
>>>> have to bend around every obstacle of solid logic. Ho hum.
>>
>>>> But suppose they were right? Don't oars flex a vastly more than any
>>>> rigger? So why would these "experts" let anyone to race with oars which
>>>> bend - not slightly but by really large amounts. Surely that must thus
>>>> be throwing away huge amounts of their rowers' output?
>>
>>>> Pure tosh, I'm afraid.
>>
>>>> BTW, the "F1" word was casually dropped into the video by the former
>>>> composites buyer of the transient Super Aguri F1 Team. Of itself that
>>>> word makes no more difference, in this context, than an anti-wrinkle
>>>> cream with a faux-scientific title makes to a woman's age.
>>
>>>> It will serve the sport best if those involved its technicalities hold
>>>> have a diminishing appreciation of the essential difference.
>>
>>>> Cheers -
>>>> Carl
>>
>>
>>
>>>> Cheers -
>>>> Carl
>>
>>
the Donoratico scar.
Perhaps in 40 years' time there'll be folk writing in, recalling their
wing-rigger shin & knuckle injuries?
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
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