Vespoli's Video on hull design
JD
website of a presentation on hull design by the America's Cup winning
designers who created Vespoli's latest creation, the "E" hull.
http://www.vespoli.com/vespoli/news/racing-shell-hull-design-what-really-matters/
BigD
> I thought I would throw this out there. It's a video from Vespoli's
> website of a presentation on hull design by the America's Cup winning
That was pretty interesting. I looked at the different hull designs
as well (E and Advantage) and it raises an interesting question for
all but the elite boats out there: If a boat was 40% more stable could
the crew apply enough extra force to compensate for the 1% increase in
drag? My experience tells me that it is probably true, but it would
be interesting to hear what others think.
Marco
on their skills/technique
Marco
Mike De Petris
> If your crew need the extra stability you should really start working
> on their skills/technique
may be really good for crews joining to race the eight as a second
race, never training together, and for selections (seat races)
:-)
Edgar
"BigD" <davidh...@hotmail.com> wrote in message
news:6928c5cb-e0bb-4f05...@s38g2000prg.googlegroups.com...
Once your blades are in the water and locked on any minor differences in the
stability of the hull itself become irrelevant.
Mike De Petris
> Once your blades are in the water and locked on any minor differences in the
> stability of the hull itself become irrelevant.
but you know almost half of the time in a race blades will be OUT and
most of this time is when the boat is faster!
Think at it, you pull so hard to make the boat flow during the
recovery.
SD...@live.com
>
> Think at it, you pull so hard to make the boat flow during the
> recovery.
Yes Mike,
that is where most of the skill and beauty in rowing lies.
I have heard of vibrational resistance on hulls due to
reflected shock waves from the river bed which is more pronounced in
shallow water, in other words nearly all water that fine racing shells
encounter.
I think that advanced control regarding entry to and exit from the
water, as well as smoothly coordinated sliding, dramatically reduce
vibration to the boat and subsequent resistance from surrounding
water.
If it looks nice it often is.
steve
BigD
> If your crew need the extra stability you should really start working
> on their skills/technique
> Marco
>
IMHO, most crews/coaches over estimate thier own ability. If it is
truly a 1% loss in speed for 40% more stability, I think you are
looking at but the top10-20 collegiate crews (US perspective) and then
elite crews would benefit from the faster hull, the rest may benefit
from a more stable platform.
If any coaches/clubs have both boats, it would be great to see some
data, same course, similar conditions multiple runs etc.
Marco
for few months per year. That is a relatively unique situation world
wide. I know it's not going to happen any time soon, but if the
system would change there wouldn't really be the need of any "extra
stability".
I'm pretty sure that many crew that had just few months to get ready
for IRA (or Stotes) wouldn't mind some extra stability.
Everyone else that has the time to work on things don't really need
that they need speed.
Marco
Carl Douglas
> You are talking about the USA where people in college or HS row just
> for few months per year. That is a relatively unique situation world
> wide. I know it's not going to happen any time soon, but if the
> system would change there wouldn't really be the need of any "extra
> stability".
> I'm pretty sure that many crew that had just few months to get ready
> for IRA (or Stotes) wouldn't mind some extra stability.
> Everyone else that has the time to work on things don't really need
> that they need speed.
> Marco
They'd get that extra stability from a better fin system. The fin (skeg
in USA) acts not just to maintain direction but also to reduce roll rate
- if properly designed. All shells are inherently unstable - their
centre of gravity (crew + boat, etc.) is higher than the roll-centre of
the boat. The key to greater stability is to reduce the roll rate to a
level that, in the cases you describe, a relatively clumsy crew is able
to control.
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)
Marco
I experimented with many different type of skegs and fins.
Unfortunately I didn't have the pleasure to use one of yours, but in
this case I thought we were talking just about the hull.
The hydro-dynamic appendixes make a big difference but in this case I
think we were talking about sacrificing some of the hull stability for
more speed or vice versa.
I personally think that especially in a 8+ with the number of hours
that are now days required to be competitive at any level this should
not be a compromise that you have to make.
Rowers should be skilled enough (or coaches should be knowledgeable
enough) to be able to handle anything.
Good fin skeg can with really minimum increase of surface and drag be
an excellent solution though.
M
> Email: c...@carldouglas.co.uk Tel: +44(0)1932-570946 Fax: -563682
> URLs: www.carldouglas.co.uk(boats) &www.aerowing.co.uk(riggers)
Carl Douglas
> I agree Carl,
> I experimented with many different type of skegs and fins.
> Unfortunately I didn't have the pleasure to use one of yours, but in
> this case I thought we were talking just about the hull.
> The hydro-dynamic appendixes make a big difference but in this case I
> think we were talking about sacrificing some of the hull stability for
> more speed or vice versa.
> I personally think that especially in a 8+ with the number of hours
> that are now days required to be competitive at any level this should
> not be a compromise that you have to make.
> Rowers should be skilled enough (or coaches should be knowledgeable
> enough) to be able to handle anything.
> Good fin skeg can with really minimum increase of surface and drag be
> an excellent solution though.
> M
>
Yes, that was just the point I was making, Marco.
A well-designed fin/rudder system will improve the stability of the
moving boat. At the same time it will enhance the boat's performance
and responsiveness.
It does not increase the wetted surface (in fact, it reduces it). It
improves the boat's hydrodynamic performance & directional control. It
reduces the parasitic drag of the fin & steering system.
Thus, with the right system (AeRowFin), you benefit in every respect.
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