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Bow ball safety

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POWER10

unread,
Oct 25, 2003, 5:33:31 PM10/25/03
to
Is there a recommended -better-bow ball device to minimize injuries, such as
actual destructive penetration?
Gordon L. Pizor
WYRA
Gordon L. Pizor
Head Coach and Associate Director
Wilmington Youth Rowing Association, Inc.
WYRA

Carl Douglas

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Oct 26, 2003, 3:05:04 PM10/26/03
to
POWER10 <pow...@aol.com> writes

As with all safety measures, you require proven performance under
realistic conditions.

There are no standards or tests for effective bow protection because
rowing's administrations have a negligent attitude to athlete safety.
This arduous & very apolitical sport is controlled by the few who are
politically manipulative & ambitious - the very sort you wouldn't want
in your crew. Their administrations tend to be self-selecting &
self-appointing. It is not evident that they have much regard for those
they supposedly represent.

This situation provides for no meaningful focus on safety. Supposed
safety functions tend to be handed out to timeservers, just as warlords
award minor lieutenants with minor fiefdoms. In consequence, equipment
safety is minimal, rowers sometimes drown or get speared & equipment
manufacturers have no properly-defined safety objectives to meet or
pursue.

Adequate bow protection requires at least the following as a Performance
Standard:
1. There should be defined and meaningful test conditions, representing
the maximum severity of direct and glancing impact to be expected in
use.
2. The protected bow shall not break away or splinter under test.
3. The protected bow, or any part thereof, shall not be able to
penetrate the protector under test or in any way be likely to contact
the flesh of a rower.
4. The area of contact, and the resulting distribution of pressure
under impact with the relevant area of a rower's body, shall be such as
to prevent both bodily perforation and/or significant injury to vital
organs - the zone of the body to be considered being defined as the legs
and all parts of the trunk below a predefined level (say the bottom of
the sternum, but numbers would be required).
5. The protector should withstand unimpaired the test impact and not
less that 5 years of typical exposure to cold, heat and sunlight.

I would note that soft rubber is useless, giving only the sense of being
protective while deforming severely under impact to concentrate the load
onto a very small contact area even if not actually pierced by the bow.

In default of such a standard, one might propose that an effective bow
protector would be made of a very hard rubber or rigid material,
coherently bonded to the bow over a length of not less than ~8cm/3"
(without screws or other mechanical fixings), with a projected frontal
area of ~25sq cm/4sq in, that frontal area having a radius of not less
than ~4cm/1.5". In addition, the bow should have sufficient integral
reinforcement to resist a strong 45-degree impact without fracture,
although credit may be taken for any reinforcing effect of the bonded-on
protector.

I suspect such a device might resemble an elliptical mushroom on its
side, the major axis of the ellipse being vertical. At present it does
not exist.

Design suggestions would be welcome

Cheers -
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing low-drag Riggers/Advanced Accessories
Write: The Boathouse, Timsway, Chertsey Lane, Staines TW18 3JY, UK
Email: ca...@carldouglas.co.uk Tel: +44(0)1784-456344 Fax: -466550
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)

Reinder Verlinde

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Oct 26, 2003, 3:34:35 PM10/26/03
to
In article <uby9UODwjCn$Ew...@rowing-cdrs.demon.co.uk>,
Carl Douglas <Ca...@carldouglas.co.uk> wrote:

> Adequate bow protection requires at least the following as a Performance
> Standard:

> [...]


> 5. The protector should withstand unimpaired the test impact

Why would one require that? Keeping the boat afloat after the impact is
a requiremtent, having the boat survive it not (think crumple zones in
cars).

Reinder

Rob Collings

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Oct 27, 2003, 3:36:47 AM10/27/03
to
Reinder Verlinde <rei...@verlinde.invalid> wrote in message news:<reinder-3E2BEB...@reader08.wxs.nl>...

Because people won't change the bow ball after a crash and it would be
hard to police. After you crash your car, if it was bad enough to
crumple the front end then it is likely something else was damaged
that needs fixing. And driving around with a mashed front end will get
you pulled over by the police. Bow balls tend to be one of those
things that get "put on the list" or fixed in time for regattas.
Unfortunately, regattas are probably the least likely scenario for a
collision bow-first.

A better analogy is, perhaps, crash helmets on bikes. These require to
be replaced after any impact as they protect by destruction and damage
is not always visible. I have seen many crashes where people have
smacked their head off something, looked at their helmet, then carried
on because "it looked OK."

Would you want to be hit by a bow ball that "looked OK" but had been
damaged previously or by one that survived its previous impact?

Rob.

Reinder Verlinde

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Oct 27, 2003, 12:50:00 PM10/27/03
to
In article <771c9d1a.03102...@posting.google.com>,
RPCol...@iee.org (Rob Collings) wrote:

> Reinder Verlinde <rei...@verlinde.invalid> wrote in message
> news:<reinder-3E2BEB...@reader08.wxs.nl>...
> > In article <uby9UODwjCn$Ew...@rowing-cdrs.demon.co.uk>,
> > Carl Douglas <Ca...@carldouglas.co.uk> wrote:
> >
> > > Adequate bow protection requires at least the following as a Performance
> > > Standard:
> > > [...]
> > > 5. The protector should withstand unimpaired the test impact
> >
> > Why would one require that? Keeping the boat afloat after the impact is
> > a requiremtent, having the boat survive it not (think crumple zones in
> > cars).
> >
> > Reinder
>
> Because people won't change the bow ball after a crash and it would be
> hard to police.

I was hinting at more than changing the bow ball after such an accident.
I think the best road to safety is for the bow of the boat to give in.
Rowers will notice such damage, and repair their boat.

Reinder

Henning Lippke

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Oct 27, 2003, 1:52:38 PM10/27/03
to

> Why would one require that? Keeping the boat afloat after the impact
> is a requiremtent, having the boat survive it not (think crumple
> zones in cars).

I guess the 'crumple zone' is the most dangerous thing in a collision,
think of the splinters going through the flesh of the rower. Therefore
it makes sense to require a bow that doesn't explode and expose all
sorts of sharp edges.

What I thought about today: Would it make sense to design bowballs
according to the boat size they are used on, ie singles and eights have
very different bow protection systems?

-HL

Neil Wallace

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Oct 28, 2003, 9:46:23 AM10/28/03
to

"Henning Lippke" <nor...@usenet.org> wrote in message
news:bnjphm$124a77$1...@ID-122207.news.uni-berlin.de...
snip

> What I thought about today: Would it make sense to design bowballs
> according to the boat size they are used on, ie singles and eights have
> very different bow protection systems?
>

I can see logic in that, Spock.

Neil Wallace

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Oct 28, 2003, 9:52:47 AM10/28/03
to

"Reinder Verlinde" <rei...@verlinde.invalid> wrote in message
news:reinder-4E7195...@reader08.wxs.nl...
snip

> I was hinting at more than changing the bow ball after such an accident.
> I think the best road to safety is for the bow of the boat to give in.
> Rowers will notice such damage, and repair their boat.
>

are you proposing some sort of material designed to "concertina" upon
impact?

Perhaps that does make some sense, I would certainly rather be hit by such a
bow (were I to have a choice in the matter). Perhaps the end 2ft of an eight
could be designed to crumple, and made easy to replace. Ideally it would be
able to differentiate between a bad landing at the pontoon and a scullers
kidneys....

Mind you, the number of scullers who scull on the wrong side of the waterway
and often in dark clothing is probably an easier issue to address
immediately.


Henning Lippke

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Oct 28, 2003, 1:10:02 PM10/28/03
to
"Neil Wallace" schrieb:

> > Would it make sense to design bowballs
> > according to the boat size they are used on, ie singles and eights
> > have very different bow protection systems?
> >
>
> I can see logic in that, Spock.

Yes, but because our Captain Kirk hasn't mentioned this option in his
specifications, I wasn't sure about it.

-HL

Neil Wallace

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Oct 28, 2003, 2:45:33 PM10/28/03
to

"Henning Lippke" <nor...@usenet.org> wrote in message
news:bnmbdp$13ho5m$1...@ID-122207.news.uni-berlin.de...
snip

> Yes, but because our Captain Kirk hasn't mentioned this option in his
> specifications, I wasn't sure about it.
>
> -HL

Captain Kirk Douglas...
does have a ring to it!


Carl Douglas

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Oct 28, 2003, 3:31:42 PM10/28/03
to
Henning Lippke <nor...@usenet.org> writes
The essence of the process for evolving effective safety equipment is
that it is done by open, intelligent & informed discussion & analysis,
unhampered by mistaken preconceptions. Involve the experts. And
everyone remember that there is no place for egos or secrecy. What
matters is that the result was right, not who came up with the right
result.

In other words, the exact opposite to how the ARA works.

Thus it does seem reasonable that a single might not need as big a
device as an eight does, but perhaps not reasonable that the device
should be "very different".

My suggestions were largely the product of my own thinking. I offered
them as a starting point. I am very sure that they can be improved
upon, & I welcome all suggestions to that end. We need the input of
many disciplines. And we all need to remember: "The next person to be
skewered through the back might be me".

I've more than once been run down, head-on, by an unseeing crew which
was completely in the wrong place. I still get flashbacks of the
shocked awareness that it is going to happen, that it might take out my
spine, & that I can do nothing to prevent it.

Henry Braun

unread,
Oct 29, 2003, 12:35:24 PM10/29/03
to
On Tue, 28 Oct 2003, Carl Douglas wrote:
>
> Thus it does seem reasonable that a single might not need as big a
> device as an eight does, but perhaps not reasonable that the device
> should be "very different".

Indeed not. Would the bowman of an eight be any happier to impale himself
on a single than the sculler would be to be impaled by the eight? The
collisions are much the same.


William R. Platt

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Oct 29, 2003, 3:26:55 PM10/29/03
to

"Henry Braun" <br...@maths.ox.ac.uk> wrote in message
news:Pine.LNX.4.58.03...@tom-slick.maths.ox.ac.uk...

> On Tue, 28 Oct 2003, Carl Douglas wrote:
> >

> SNIP


> Indeed not. Would the bowman of an eight be any happier to impale himself
> on a single than the sculler would be to be impaled by the eight? The
> collisions are much the same.


The collsions are not at all the same. An eight weighs 1 metric ton +/-,
whereas a single is 0.1 metric ton (100 kg). So if the velocities are the
same, the eight has 10 times the kinetic engergy. In a collision, 8 ramming
1, (or 1 ramming 8) the 1 and sculler will be torn to shreds as the eight
barely slows--the "approved" bow ball now nestled along side the kidneys of
the sculler.

On the other hand, 8 running into an 8, oh my god, that is just catastrophe
in the making--you have 10 times more energy to dissipate as the bow ball
enters the bowman's back, goes clean through, and carries him forcefully
into #2's back, etc. It is a frightful thing to imagine.

So, whereas a single can only throw its 0.1 tons at 9 knots of energy
around, no matter what it hits, the 8, when ramming a single, is bad, but
ramming another 8, is frightful. And furthermore, the 8 can go better than
11 knots!


So, NO, there is no one "bow ball" to make for equal protection among the
various sizes of boat.. Mr. Douglas is absolutely correct in stating that
there should be a rational, informed discussion requiring input from persons
who are trained and actively professionally engaged in matters of kinetics,
dynamics, collisions, naval architecture etc.

What you will find, if you bother to go through this excersize, is that no
current design for an 8 or a 4, and probably not for 2x or 1 either, would
be acceptable from a crash safety standpoint. The bow is a rapier. To
avoid puncture, you must have a blunt object---which would require a flat or
hemispherical bulkhead roughly 50 to 100 cm aft of the stemhead (for an
eight, say). The boat from there to the stemhead would have to be a "foam"
or other highly conformable material. Even with these adjustments, you
still have no way to ensure that the person rammed is not seriously injured
from a broken back or other shock-induced injury. Yes, it is entirely
possible to build boats to meet this criterion. But it will not happen
unless the "powers" decide that it must.

But I rather suspect that nothing of the sort will ever happen. After all,
the sport is old and established, and relatively elite and marginal---not
apt to catch the polititian's awareness--and yes, terrible collisions are
infrequent (perhaps not rare, though).

Also, look at the broader statitistics in the US: annual boating
fatalities: 500 +/-250, most due to drowning (roughly 80%) and a goodly
number of the rest due to collisions. Deaths per annum on the highways:
better than 40,000 per year--depending on what you count (trucks,
motorcycles, pedestrians or not etc). Even NYC alone, until recently, saw
in excess of 300 pedestrians killed every year. Basically, nobody
"important" cares about rowing fatalities.


regards,


Bill Platt
http://plattdesign.net

Henning Lippke

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Oct 29, 2003, 4:03:32 PM10/29/03
to
"William R. Platt" schrieb:

>
> The collsions are not at all the same. An eight weighs 1 metric ton
> +/-, whereas a single is 0.1 metric ton (100 kg). So if the
> velocities are the same, the eight has 10 times the kinetic engergy.
> In a collision, 8 ramming 1, (or 1 ramming 8) the 1 and sculler will
> be torn to shreds as the eight barely slows--the "approved" bow ball
> now nestled along side the kidneys of the sculler.
>
> On the other hand, 8 running into an 8, oh my god, that is just
> catastrophe in the making--you have 10 times more energy to
> dissipate as the bow ball enters the bowman's back, goes clean
> through, and carries him forcefully into #2's back, etc. It is a
> frightful thing to imagine.

So, what about an installation which prevents the bow from entering the
crew room? Something like a 'roll-bar' on rally cars, that pushes the
bow slightly to any side (in a head-to-head crash). Then we have no
sharp bows pointing at rowers and have to care about the impact of oars
and riggers (which is probably needed anyway).

Ok, there's still the danger of running perpendicular into another boat,
but that needs a bit of evil intent IMO. For any other directions,
pushing the bow elsewhere seems to be fine at first sight.

Ideas?

David Gillbe

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Oct 29, 2003, 5:31:26 PM10/29/03
to
> > SNIP
> > Indeed not. Would the bowman of an eight be any happier to impale
himself
> > on a single than the sculler would be to be impaled by the eight? The
> > collisions are much the same.
>
>
> The collsions are not at all the same.

In my limited knowledge of physics, I believe that you're talking rubbish.
The momentum of the eight and the momentum of the single are indeed
different. However, surely, when they collide, the impulse will be the same,
whether the eight collides with the single, or the single collides with the
eight. If (it would take some supremely skilled steering to replicate this,
thank god), a single managed to hit the bowman of an eight, though the eight
would push the single back (as you suggest), the bow of the single would go
straight through the bowman. The impact would carry exactly as much force
that way, as if the collision were the other way round.
(I'm fairly sure on that much - please would a mathmo (Henry?) correct me if
I'm wrong - from here onwards though I'm stabbing around in the dark a bit)
Indeed, the damage caused by the scull to the bowman may be worse, since the
force would be spread over a smaller area (since the bow of a single has a
smaller cross sectional area than the bow of an eight - I think?). Perhaps
here we see were bowball design could be improved. Surely there are two
options - either to design something that will absorb much of the force of
the impact (think a giant spring - e.g. a car suspension) From what I can
tell, this was the reasoning (if you can call it that) behind using soft
rubber. The other option is to spread the force of the collision out over a
larger area. It's an oft quoted fact that a woman in a stiletto will do far
more damage standing on your foot than an elephant. Yes, we may have huge,
very sore bruises if we are unfortunate (or unskilled) enough to be in such
a collision, but at least we won't have a gut full of fibreglass (or
whatever it is they make boats out of).

Taking this to extremes, the ideal bow"ball" would be something that does
both - absorbs much of the force in the impact (like a car crumple zone, or
a spring) and also spreads out the force so as to cause injuries, but not
penetrating injuries (think sticking a large hardback book on the front of a
boat. You can have my copy of Varian "intermediate microeconomics" if you
want.

Just my thoughts - I'm sure someone more intelligent than I can represent
them mathematically and come up with an optimum design which maximises both
the absorption and the "spreading out" effect.

Dave


David Gillbe

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Oct 29, 2003, 5:35:47 PM10/29/03
to
> from here onwards though I'm stabbing around in the dark a bit

Again, sorry to reply to myself. Just saw this phrase in my last post and
realised how inappropriate it was. Apologies to anyone offended.


Carl Douglas

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Oct 29, 2003, 4:47:05 PM10/29/03
to
Henning Lippke <nor...@usenet.org> writes

Bill is deadly right about the impact energy balance. The bowman of an
eight hit by a sculler is driven forward through his stretcher by the
momentum of the rest of the eight & its crew but only has to reverse one
sculler. When hit by another eight his back has to absorb in a small
fraction of a second the entire kinetic energy of both eights.

There's much variability in the nature & intensity of impact, depending
upon where the target rower & striking crew are in their stroke cycles,
& the direction of the impact. In a head-on collision, if everyone in
the striking crew is at the finish & the target rower is in mid pull,
then the damage will be far more severe than if both crews are
half-forward. And in a side-impact the striking bow will rip right
across flesh, as well as into it.

On Henning's point:
Impaling bows seem well able to over-ride the side of even an eight.
They go straight over the sides of singles. So, while I see the sense
in his suggestion, it seems better to try to make the bow a safer thing
to be hit by than to turn all boats into defensive walls around their
crews.

Henry Braun

unread,
Oct 30, 2003, 5:15:30 AM10/30/03
to
On Wed, 29 Oct 2003, William R. Platt wrote:

> The collsions are not at all the same. An eight weighs 1 metric ton +/-,
> whereas a single is 0.1 metric ton (100 kg). So if the velocities are the
> same, the eight has 10 times the kinetic engergy. In a collision, 8 ramming
> 1, (or 1 ramming 8) the 1 and sculler will be torn to shreds as the eight
> barely slows--the "approved" bow ball now nestled along side the kidneys of
> the sculler.

Oh, I can do the maths. But if the bowman of the eight stops his boat by
pushing the scull backwards through the water with the scull's bowball in
his kidneys, he's going to be just as unhappy as the sculler would be
stopping the eight with *his*.

I suppose it's an extreme scenario, if most collisions broadside one boat
or the other, when only the momentum of the spearing boat matters.

felipe

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Oct 30, 2003, 7:45:10 AM10/30/03
to
"William R. Platt" <wpl...@takeouthormelplattdesign.org> wrote in message news:<GOudnR_hhpq...@thebiz.net>...

> "Henry Braun" <br...@maths.ox.ac.uk> wrote in message
> news:Pine.LNX.4.58.03...@tom-slick.maths.ox.ac.uk...
> > On Tue, 28 Oct 2003, Carl Douglas wrote:
> > >
>

[...]

> What you will find, if you bother to go through this excersize, is that no
> current design for an 8 or a 4, and probably not for 2x or 1 either, would
> be acceptable from a crash safety standpoint. The bow is a rapier. To
> avoid puncture, you must have a blunt object---which would require a flat or
> hemispherical bulkhead roughly 50 to 100 cm aft of the stemhead (for an
> eight, say). The boat from there to the stemhead would have to be a "foam"
> or other highly conformable material. Even with these adjustments, you
> still have no way to ensure that the person rammed is not seriously injured
> from a broken back or other shock-induced injury.


Good thing, then, that these sorts of accidents are (and I'll say it)
extremely rare, nigh freakish, especially given the number of crews
and the number of hours crews practice in the US. Getting whacked by
an oar seems much more common -- and not surprisingly so. Given that
riggers and oars do a lot to protect boats from the side, the area in
which the bow of one boat can hit another is pretty small.

Obviously, though, it can and sometimes does happen.

I'll continue my nattering nabobery with an old joke. Two guys are
discussing going to Cleveland. One says, Maybe we should take the
train instead of fly. The other says, I haven't taken a train in ten
years. The first says, why not. Second: I was on a train once,
going along fine, and WHAM! First: What happened? Second: An
airplane fell on it.

It's not a good joke, and offensive given the circumstances. Someone
was hurt, and that's a tragedy.

But there's a point to it. Namely, you could reinforce the tops of
trains to protect against falling aircraft. Surely everyone would be
safer. But airplanes falling onto trains is exceedingly rare.

Now, exhale. I know head-on collisions between shells is not that
rare, but it is pretty darned uncommon. Putting a roll-bar on the
front of shells, or laminating all boats with several inches of thick
padding, might not only play hell with fluid and aerodynamics but
might be a wasted effort, given how often these things actually do
happen.

Before someone accuses me of giving them intestinal distress again, I
want to emphasize that redesigning bowballs is a good idea. And, as
the author says below, waiting for politicians (politicians??) to do
something about this "issue" is silly.

So why wait?

At least three boatbuilders read this forum, maybe more. Build a
better bowball. Send samples to the ARA, USRowing, NCAA, FISA,
whatever the governing body is in Australia or Canada. Send a lengthy
description about how this is better than the poor excuses that lead
boats into battle now. Change things.

Just recognize that better bowballs won't prevent collisions. And
head-on collisions the sort that happened in CT, are, in fact, pretty
darned rare -- thankfully. As Will Platt points out, even with a
better bow design, two eights colliding head on will probably cause
pretty dire injury.

William R. Platt

unread,
Oct 30, 2003, 8:37:57 AM10/30/03
to

"Henry Braun" <br...@maths.ox.ac.uk> wrote in message
news:Pine.LNX.4.58.03...@danger-mouse.maths.ox.ac.uk...

> On Wed, 29 Oct 2003, William R. Platt wrote:
>
> > The collsions are not at all the same. An eight weighs 1 metric ton
+/-,
> > whereas a single is 0.1 metric ton (100 kg). So if the velocities are
the
> > same, the eight has 10 times the kinetic engergy. In a collision, 8
ramming
> > 1, (or 1 ramming 8) the 1 and sculler will be torn to shreds as the
eight
> > barely slows--the "approved" bow ball now nestled along side the kidneys
of
> > the sculler.
>
> Oh, I can do the maths. But if the bowman of the eight stops his boat by
> pushing the scull backwards through the water with the scull's bowball in
> his kidneys, he's going to be just as unhappy as the sculler would be
> stopping the eight with *his*.
>

Yes, you are right Henry--Sorry for the short-hand notation in my 1st post--
the "(or 1 ramming 8)" was meant to show that yes indeed, the bowman of the
8 and the singles sculler are in very similar predicaments regarding energy
of impact. What I was objecting to more was the (perhaps incorrect
inference) that all collisions regardless of boat size will be the same.


> I suppose it's an extreme scenario, if most collisions broadside one boat
> or the other, when only the momentum of the spearing boat matters.


What my most imprtant point is, though, is that there is an awful lot of
energy to be dealt with--and no "bow ball" is ever going to be adequate.
And that further, the bigger boats are very definitely more "dangerous" in
this respect--more potential energy to deal with.

BTW, a co-worker of mine who rowed in college told yesterday of a T-bone
crash on the Schuylkill back in his day--we must not forget the 90 degree
condition--and both 8s went down in seconds--and the oarsman who was at the
site of the impact had the tops of his legs torn up bt the colliding 8
raking over him.

So, The idea of a roll cage, further up the thread, is not a particularly
effective one.

Regards,

Bill

William R. Platt

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Oct 30, 2003, 9:03:15 AM10/30/03
to
Hello Felipe, (Bill Platt here),


"felipe" <fel...@eudoramail.com> wrote in message
news:301f6623.03103...@posting.google.com...


> "William R. Platt" <wpl...@takeouthormelplattdesign.org> wrote in message
news:<GOudnR_hhpq...@thebiz.net>...
> > "Henry Braun" <br...@maths.ox.ac.uk> wrote in message
> > news:Pine.LNX.4.58.03...@tom-slick.maths.ox.ac.uk...
> > > On Tue, 28 Oct 2003, Carl Douglas wrote:
> > > >
> >
>
> [...]
>

> > BPLATT: What you will find, if you bother to go through this excersize,


is that no
> > current design for an 8 or a 4, and probably not for 2x or 1 either,
would
> > be acceptable from a crash safety standpoint. The bow is a rapier. To
> > avoid puncture, you must have a blunt object---which would require a
flat or
> > hemispherical bulkhead roughly 50 to 100 cm aft of the stemhead (for an
> > eight, say). The boat from there to the stemhead would have to be a
"foam"
> > or other highly conformable material. Even with these adjustments, you
> > still have no way to ensure that the person rammed is not seriously
injured
> > from a broken back or other shock-induced injury.
>
>

> FELIPE: Good thing, then, that these sorts of accidents are (and I'll say


it)
> extremely rare, nigh freakish, especially given the number of crews
> and the number of hours crews practice in the US. Getting whacked by
> an oar seems much more common -- and not surprisingly so. Given that
> riggers and oars do a lot to protect boats from the side, the area in
> which the bow of one boat can hit another is pretty small.

<SNIP>
>
>FELIPE: Now, exhale. I know head-on collisions between shells is not


that
> rare, but it is pretty darned uncommon. Putting a roll-bar on the
> front of shells, or laminating all boats with several inches of thick
> padding, might not only play hell with fluid and aerodynamics but
> might be a wasted effort, given how often these things actually do
> happen.


BPlatt: Actually, the soft bow is not a big deal to do at all--even with
current construction techniques--and there would be no effect on the fluid
dynamics. You merely put a dam in the mold 50cm or so aft of the stemhead,
mold up the hull, pull the hull, put the dam back in but with the shiny side
facing forward, fill the void with 45 kg/m^3 foam (3 pcf). The last 10 cm
or so might want to be a low-modulus type of resilient foam--would have to
do some computing to be sure---but 45 density foam is quite easy to crush
with the fingers.

Then, you affix the foam to the hull (having designed a mortise and tenon
joint that is molded into the bulkhead) with some 3m 4200 adhesive on the
whole bulkead, then paint it up, and VoilĂ ! The foam is more than stiff
enough for hydrodynamics, and has the same finish as the rest of the boat.

> FELIPE:


> Before someone accuses me of giving them intestinal distress again, I
> want to emphasize that redesigning bowballs is a good idea. And, as
> the author says below, waiting for politicians (politicians??) to do
> something about this "issue" is silly.
>
> So why wait?
>
> At least three boatbuilders read this forum, maybe more. Build a
> better bowball. Send samples to the ARA, USRowing, NCAA, FISA,
> whatever the governing body is in Australia or Canada. Send a lengthy
> description about how this is better than the poor excuses that lead
> boats into battle now. Change things.
>

Bill Platt: Forget the bowball--if you are serious about collisions. It has
to be a more substantial protection to be effective. The bow ball is good
only for bumping into people while you are walking the boat up the apron!

<SNIPPED>

And, good to be a nattering nabob when it helps get perspective.


Best regards,

Bill


William R. Platt

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Oct 30, 2003, 9:22:56 AM10/30/03
to

"William R. Platt" <wpl...@takeouthormelplattdesign.org> wrote in message
news:GLydnbYEGb5...@thebiz.net...

> Hello Felipe, (Bill Platt here),
>
SNIP

>
> Then, you affix the foam to the hull (having designed a mortise and tenon
> joint that is molded into the bulkhead) with some 3m 4200 adhesive on the
> whole bulkead, then paint it up, and VoilĂ ! The foam is more than stiff
> enough for hydrodynamics, and has the same finish as the rest of the boat.
>


Of course, if you are out on the Schuylkill or some other river that gets a
lot of snags after a rain, the foam bow may not do very well when it hits
floating branches. So, what else to do--it starts to get more
complicated-now you need a hard skin on the lower portions of the foam--but
it must be a tough material (not splintery) and free to break away and fold
back in a collision--just brainstorming here.....


felipe

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Oct 30, 2003, 10:19:37 AM10/30/03
to
Henry Braun <br...@maths.ox.ac.uk> wrote in message news:<Pine.LNX.4.58.03...@danger-mouse.maths.ox.ac.uk>...

Do most collisions occur broadside? Or, put another way, do the ones
that occur broadside pose as much a danger due to bowball? Don't oars
and riggers tend to get in the way?

Mark McMillan

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Oct 30, 2003, 11:03:18 AM10/30/03
to
One thing I have learnt from personal experience is that the riggers provide
a very effective ramp in enabling the bow of one boat to ride up into the
crew space in other boat.
Blades will only tend to redirect (rather than stop) the marauding boat.

Nick Suess

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Oct 30, 2003, 8:35:29 PM10/30/03
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felipe <fel...@eudoramail.com> wrote in message

>...... Build a better bowball.

Now what did your very own Ralph Waldo Emerson say?

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