Re: [bolger] Re: Keel Designs
No it was just a dumb typo - but I noticed it after I posted and thought
"actually it almost makes sense that way too :) "
Chris
R Coy wrote:
"actually it almost makes sense that way too :) "
Chris
R Coy wrote:
>
> Was that Freuidien or what?
> Roger
>
> ---cml@...wrote:
> > Also as the boat hells the depth of the keel
> > increases ie when it is most needed.
> >
> > The book "Principles of Yacht Design" by Larsson and
> > Eliasson discusses
> > wing keels in some detail.
Was that Freuidien or what?
Roger
---cml@...wrote:
Do You Yahoo!?
Thousands of Stores. Millions of Products. All in one Place.
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Roger
---cml@...wrote:
>__________________________________________________
>
> Peter Vanderwaart wrote:
> >
> > > At the risk of starting another fire storm of
> activity
> > > like "physics", does anyone know how the
> Austrailian Wing keel is
> > > designed?
> >
> > The short answer is, 'No, I don't now how a wing
> keel is designed.'
> > But I do have some comments that might be helpful.
> ...
> > There are two
> > major considerations, as I understand it. First,
> the hydrodynamic
> > consideration of having the wing produce a end
> plate effect. A more
> > or less ordinary understanding of the tip vortex
> phenomenon and a
> > look at some existing designs will get you about
> 50% of the way
> > there. Second, there is the ballast effect of the
> weight in the
> > wings. This is not a difficult matter.
>
> Also as the boat hells the depth of the keel
> increases ie when it is
> most needed.
>
> The book "Principles of Yacht Design" by Larsson and
> Eliasson discusses
> wing keels in some detail.
>
> Chris
>
Do You Yahoo!?
Thousands of Stores. Millions of Products. All in one Place.
http://shopping.yahoo.com/
Peter Vanderwaart wrote:
most needed.
The book "Principles of Yacht Design" by Larsson and Eliasson discusses
wing keels in some detail.
Chris
>...
> > At the risk of starting another fire storm of activity
> > like "physics", does anyone know how the Austrailian Wing keel is
> > designed?
>
> The short answer is, 'No, I don't now how a wing keel is designed.'
> But I do have some comments that might be helpful.
> There are twoAlso as the boat hells the depth of the keel increases ie when it is
> major considerations, as I understand it. First, the hydrodynamic
> consideration of having the wing produce a end plate effect. A more
> or less ordinary understanding of the tip vortex phenomenon and a
> look at some existing designs will get you about 50% of the way
> there. Second, there is the ballast effect of the weight in the
> wings. This is not a difficult matter.
most needed.
The book "Principles of Yacht Design" by Larsson and Eliasson discusses
wing keels in some detail.
Chris
Roger,
The reason the Aussies went with the original wing keel on the 12
Meter was because of the way the 12 Meter rule works. A bunch of
dimensions - various hull girths, freeboard, sail area, draft,
displacement, waterline length, plus more - must equal 12 meters.
It's a slipery rule. If you increase sail area, for example, you have
to reduce, say, maximum beam, in order to meet the rule. The
designers traded certain elements off in order to gain somewhere else.
The Aussies derived (with the help of some Dutch guy, I think) the
winged keel to get around these trade-offs. They could get more
lateral resitance (when heeled) and stability by putting less ballast
concentrated down low. The reduced draft allowed them to go big in
another design area (I can't remember where). I worked.
Thus started a fad among cruising boats. Winged keels aren't
necessarily more "efficient" than a deep, high aspect fin. They are
more efficient, though, in certain circumstances. You gain lateral
resistance as you heel, ballast is carried lower, end plate effect
(depending on wing shape and size, and draft is less when the boat's
upright.
Disadvantages are cost, snagging weed and pot warps (they just
won't slide off as easily), wing strength issues, and overkill. If
you sail a lot in very shallow water, then they're fine, especially
if you have a bg boat.
A deep fin is cheaper, stronger (except for extreme examples), and
better in deep water with big waves.
If you're going to cruise, I'd go for a boat with a long fin with
the rudder mounted on a sizeable skeg, or a full keel. Over long
distances, these keels allow the helmsman to relax. The speed per
1,000 miles is likely to be as fast, or faster, because the crew
doesn't have to concentrate as deeply to keep the boat from sliding
sideways. Plus they'll be able to party on arrival, instead of
nursing sore shoulders and blistered palms.
I agree with Peter, this wing keel thing is still under
developement. The latest America's Cup class boats keels were all
over the road. Some had the wings at the aft end of the bulb, some
towards the middle. Some wings tapered more than others. The sizes
varied widely. Some were parallel with the water surface, others
angled down.
I hope this helps.
Take care,
Pete Reynolds
The reason the Aussies went with the original wing keel on the 12
Meter was because of the way the 12 Meter rule works. A bunch of
dimensions - various hull girths, freeboard, sail area, draft,
displacement, waterline length, plus more - must equal 12 meters.
It's a slipery rule. If you increase sail area, for example, you have
to reduce, say, maximum beam, in order to meet the rule. The
designers traded certain elements off in order to gain somewhere else.
The Aussies derived (with the help of some Dutch guy, I think) the
winged keel to get around these trade-offs. They could get more
lateral resitance (when heeled) and stability by putting less ballast
concentrated down low. The reduced draft allowed them to go big in
another design area (I can't remember where). I worked.
Thus started a fad among cruising boats. Winged keels aren't
necessarily more "efficient" than a deep, high aspect fin. They are
more efficient, though, in certain circumstances. You gain lateral
resistance as you heel, ballast is carried lower, end plate effect
(depending on wing shape and size, and draft is less when the boat's
upright.
Disadvantages are cost, snagging weed and pot warps (they just
won't slide off as easily), wing strength issues, and overkill. If
you sail a lot in very shallow water, then they're fine, especially
if you have a bg boat.
A deep fin is cheaper, stronger (except for extreme examples), and
better in deep water with big waves.
If you're going to cruise, I'd go for a boat with a long fin with
the rudder mounted on a sizeable skeg, or a full keel. Over long
distances, these keels allow the helmsman to relax. The speed per
1,000 miles is likely to be as fast, or faster, because the crew
doesn't have to concentrate as deeply to keep the boat from sliding
sideways. Plus they'll be able to party on arrival, instead of
nursing sore shoulders and blistered palms.
I agree with Peter, this wing keel thing is still under
developement. The latest America's Cup class boats keels were all
over the road. Some had the wings at the aft end of the bulb, some
towards the middle. Some wings tapered more than others. The sizes
varied widely. Some were parallel with the water surface, others
angled down.
I hope this helps.
Take care,
Pete Reynolds
--- Inbolger@egroups.com, dbcoy@y... wrote:
> At the risk of starting another fire storm of activity
> like "physics", does anyone know how the Austrailian Wing keel is
> designed?
> What are the principles behind the chosen angles?
> What type of crusing hull would this work on?
> Can it be a ballested type keel?
> If so would you use ballest bulb tanks at the ends of the wing?
> I know this detracts from the SD-SR design most of you are into.
I'm
> thinking of spending a few years on the high/low/high/low seas..."I
> think I seasick"...and I'm looking at a lot of different hull
designs.
> This group seems very knowledgable about coastal as well as open
> water sailing and I'm open to input.
> Roger
>
> PS
> And by the way, I have a 40 gal gas HW tank that works if you
> want/need one or want to convert it into a lead smolter for pouring
> your own keel. It is free and in NW Ohio. If interested please
> contact me directly.
> At the risk of starting another fire storm of activityThe short answer is, 'No, I don't now how a wing keel is designed.'
> like "physics", does anyone know how the Austrailian Wing keel is
> designed?
But I do have some comments that might be helpful.
First, ALL the final tuning of world class wing keels is done based
on tank testing, as far as I know. There is probably some very high-
priced, computer cycle-intensive software out there to get the
designs into the ball park, maybe even into the infield, before
testing. Differences in the keel designs of the most recent America's
Cup class boats suggest to me that the final chapter has yet to be
written.
Second, at a more normal level of non-optimality, I think there are
some reasonably standard keel designs (hydrokeel?) that can be
adapted to most any fin keel boat. At some level, it doesn't pay to
take it too, too, too, too seriously, given the keel designs of some
boats that have sailed around the world in the past. There are two
major considerations, as I understand it. First, the hydrodynamic
consideration of having the wing produce a end plate effect. A more
or less ordinary understanding of the tip vortex phenomenon and a
look at some existing designs will get you about 50% of the way
there. Second, there is the ballast effect of the weight in the
wings. This is not a difficult matter.
My boat, a Capri 22, has a wing keel. I have been very pleased by the
combination of shallow draft and good performance.
Peter
At the risk of starting another fire storm of activity
like "physics", does anyone know how the Austrailian Wing keel is
designed?
What are the principles behind the chosen angles?
What type of crusing hull would this work on?
Can it be a ballested type keel?
If so would you use ballest bulb tanks at the ends of the wing?
I know this detracts from the SD-SR design most of you are into. I'm
thinking of spending a few years on the high/low/high/low seas..."I
think I seasick"...and I'm looking at a lot of different hull designs.
This group seems very knowledgable about coastal as well as open
water sailing and I'm open to input.
Roger
PS
And by the way, I have a 40 gal gas HW tank that works if you
want/need one or want to convert it into a lead smolter for pouring
your own keel. It is free and in NW Ohio. If interested please
contact me directly.
like "physics", does anyone know how the Austrailian Wing keel is
designed?
What are the principles behind the chosen angles?
What type of crusing hull would this work on?
Can it be a ballested type keel?
If so would you use ballest bulb tanks at the ends of the wing?
I know this detracts from the SD-SR design most of you are into. I'm
thinking of spending a few years on the high/low/high/low seas..."I
think I seasick"...and I'm looking at a lot of different hull designs.
This group seems very knowledgable about coastal as well as open
water sailing and I'm open to input.
Roger
PS
And by the way, I have a 40 gal gas HW tank that works if you
want/need one or want to convert it into a lead smolter for pouring
your own keel. It is free and in NW Ohio. If interested please
contact me directly.