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Older well known IOR Boats


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10 hours ago, BOI Guy said:

I pulled it in and trimmed it, thats the job isn't it?

Does that make me a rock star too?

Watched some guys on a couple of TP52's have a pissing contest at the dock a couple of months ago, hauling man up the mast, what a bunch of pussies. All you could hear was the wine of the electric winch.

We could get 8 men linked up on the grinders, would have left them for dead, young guns would shit themselves going up like that these days.

4 guys on a 12M would lift the forward hand to the masthead in 8 seconds!

And that was with "vortex generators"  otherwise described as outward pointing rivets every couple of inches up both sides of the mast.  Did wonders for the inner thighs.  just occasionally mast/grinder ain't the worst spot to be.

Brought him down nearly as quick by having him roll into the main & opening letting go the halyard,  one turn on the winch to stop him about 5 feet above the boom.  Nylon jocks would melt on the way down.

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Me too.  A blooper gybe right outside the StFYC is a thing of beauty for the spectators on the roof.  Unless it's not.

I do remember a fine comment from a bow guy on Williwaw in the Admiral's Cup, 1981 I think.  Dennis Conner was driving, and he loved double-head rigs, and sometimes triple-head with two staysails.  Th

Bob Perry posted an article a couple of years back that I think is a really good overview of the IOR system.  Posting here with his permission.... Time to sit up straight and spit your gum out. W

Posted Images

8 hours ago, Richard2249 said:

On the topic of busy foredeck crews, I reckon this is a great shot - really looks like the bowman's got a bit on, regardless of whether the boat's approaching a wing mark or bottom mark.

Anyone know which boat this is out of interest?

Blooper action.jpg

That’s a shit show waiting to happen.

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1 hour ago, TUBBY said:

4 guys on a 12M would lift the forward hand to the masthead in 8 seconds!

And that was with "vortex generators" otherwise described as outward pointing rivets every couple of inches up both sides of the mast.  Did wonders for the inner thighs.  just occasionally mast/grinder ain't the worst spot to be.

Brought him down nearly as quick by having him roll into the main & opening letting go the halyard,  one turn on the winch to stop him about 5 feet above the boom.  Nylon jocks would melt on the way down.

Lars Bergstrom and his B&R rig design was a big advocate of vortex generators....he was the co designer of the Windex and the of his ideas in the 60's and 70's can be seen on modern hi tech sailboats as the engineering /materials caught up to his dream...he and his partner the "R" in B&R was Sven Ridder , both were aeronautical engineers 

IMG_0051.jpg

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53 minutes ago, BravoBravo said:

Lars Bergstrom and his B&R rig design was a big advocate of vortex generators....he was the co designer of the Windex and the of his ideas in the 60's and 70's can be seen on modern hi tech sailboats as the engineering /materials caught up to his dream...he and his partner the "R" in B&R was Sven Ridder , both were aeronautical engineers 

IMG_0051.jpg

Didn't Evolution, the Craig Walters 30' 1 tonner owned by Tony Johnson, ie Competition Sails,  have those?

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9 minutes ago, sledracr said:

.and Shenandoah to weather.

At a start if I remember. The whole fleet started together in those days.

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Diva and Charisma in the same series. Also Container, Too Impetuous, Hitchhiker, Caiman and ?? Diva was the sensation of the year, but had a few bad moments including the famously photographed Brambles grounding. Steered by Yves Pajot. Top boat was Magistri from our Canadian team (I was on Charisma) and I sold her to Sweden doubling up on having done the same with Swuzzlebubble two years before.

83.thumb.jpg.56f18bb8b1658049ae06c64019c68640.jpg

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3 minutes ago, SF Woody Sailor said:

Charisma is a splendid name for a boat. 

Names....something that is missing in today's racing , something about a custom or dedicated race boat that is completely missing today, well to the masses  

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12 hours ago, Hitchhiker said:

What TP52's have an electric winch? 

Come to think of it.  What TP52's even have space for an electric winch? 

 

However, if you could get the winch motors to also droop hike on the beats, some MedCup program manager might think about it.  

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1 hour ago, cms said:

Sov at the helm, AC83.

1017758879_LocuraMarkSoverellAC83.thumb.jpg.a5e19dabb522d8d4972a6a4c25d4e2ed.jpg

That's a cockpit designed around a Starboat driver.  Hydraulic pump right there, traveler right there, hatch to yell at the navigator right there, repeaters right there, runner winch and checkstay cascade right there.  

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3 hours ago, cms said:

Sov at the helm, AC83.

1017758879_LocuraMarkSoverellAC83.thumb.jpg.a5e19dabb522d8d4972a6a4c25d4e2ed.jpg

Looking at that photo, I assume the helmsman's feet are in a "hole" barely big enough for someone to stand in, between a midline locker/hatch(?) and the side deck.  That just seems like a nice place to break a leg, should things go sideways.

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6 hours ago, cms said:

Diva and Charisma in the same series. Also Container, Too Impetuous, Hitchhiker, Caiman and ?? Diva was the sensation of the year, but had a few bad moments including the famously photographed Brambles grounding. Steered by Yves Pajot. Top boat was Magistri from our Canadian team (I was on Charisma) and I sold her to Sweden doubling up on having done the same with Swuzzlebubble two years before.

83.thumb.jpg.56f18bb8b1658049ae06c64019c68640.jpg

What kind of boat was Diva?

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On 4/10/2020 at 8:53 AM, SF Woody Sailor said:

Corollary question: I have been thinking about picking up a second hand blooper for my boat (36 footer). Would I be able to find any bowmen or bowchicks in the SF Bay area who know how to buoy race a blooper? Or are they extinct?

War Dog. Or me.

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Diva was built for Bernard Moureau by Hervé in la Rochelle. She was a genuine breakthrough boat, opening the way for the wave of one tonners that followed from Andrieu, Briand, Judel/Vrolijk and eventually most designers.

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On 4/13/2020 at 9:30 PM, ROADKILL666 said:

That’s a shit show waiting to happen.

Back when bowmen where gods.

Now they whinge if that have to peel an Asso in  over 15 knots.

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On 4/13/2020 at 12:56 PM, Richard2249 said:

On the topic of busy foredeck crews, I reckon this is a great shot - really looks like the bowman's got a bit on, regardless of whether the boat's approaching a wing mark or bottom mark.

Anyone know which boat this is out of interest?

Blooper action.jpg

for the post before

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10 hours ago, ROADKILL666 said:

Thanks.Now I have proof.My dad and I had a bet from the 80s on what she was.Now to get him to pay up .

Do I get a "finder's fee"?  A bet made in the 80's should have more than doubled now w/inflation! ;-)

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On 4/12/2020 at 10:56 PM, Richard2249 said:

On the topic of busy foredeck crews, I reckon this is a great shot - really looks like the bowman's got a bit on, regardless of whether the boat's approaching a wing mark or bottom mark.

Anyone know which boat this is out of interest?

Blooper action.jpg

 

 

That's an awesome shot!!!  Do you have one of that zoomed out just a bit??  I would love to make a letter sized print of that pic....

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10 minutes ago, JoeO said:

Do I get a "finder's fee"?  A bet made in the 80's should have more than doubled now w/inflation! ;-)

It for 20.00 in the 80s so I am going to tell him 100.00 that should be a laugh.

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38 minutes ago, lydia said:

Back when bowmen where gods.

Now they whinge if that have to peel an Asso in  over 15 knots.

Though that environment was admirably geared towards killing us all.

200w_d.gif 

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21 minutes ago, shaggybaxter said:

Though that environment was admirably geared towards killing us all.

200w_d.gif 

Awe come on...most of us made it. A bit scarred and war torn. But, we made it.

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1 hour ago, ROADKILL666 said:

It for 20.00 in the 80s so I am going to tell him 100.00 that should be a laugh.

It should be $200.

If he gives you attitude, tell him to name 5 things that don't cost 10X what they did when you made the bet. ;)

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10 minutes ago, TUBBY said:

My daughter wears a shirt that says

IMORTAL

(so far)

 

All of us that are still here made it!

I hope your daughter can spell better than that.

 

Guy jumps off the Empire State building.  Halfway down he says to himself, "So far, so good."

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On 4/13/2020 at 5:54 AM, BravoBravo said:

Lars Bergstrom and his B&R rig design was a big advocate of vortex generators... he and his partner the "R" in B&R was Sven Ridder , both were aeronautical engineers 

IMG_0051.jpg

The vortex generators are too far aft on this rig. Clearly, they might have been aeronautical engineers, but they did not do their due diligence in reading the technical papers of the day.

Here is the paper they should have read. I did. In fact, I was in the audience at the AIAA Aero/Hydronautics of Sailing conference when Gentry presented this paper. He brought along the wind tunnel test articles shown in pictures in the paper.

http://gentrysailing.com/pdf-theory/Studies-of-Mast-Section-Aerodynamics.pdf

"This is because the peak-velocity point on the mast is always forward of the maximum width point ... the boundary layer is tripped to turbulent, the flow will separate at the peak velocity point."

Therefore, the boundary layer has already tripped BEFORE getting to the vortex generators. Hence, the vortex generators in the above picture were simply weight aloft.

"If the boundary layer could be made to trip from the laminar state to the turbulent state before the peak velocity is reached, then it would stay attached longer."

The peak velocity is roughly where the mast is thickest when looking at it from the apparent wind, 30 degrees to the side. Not from directly ahead. Hence, the strips needed to be forward about two or three widths of those rivet-strips to have any aero effect.

If anyone actually reads that paper, on page 6 there is a section called "B" that was used on Kindred Spirit, originally owned by Bob Barton (perhaps hence the "B"). Kindred Spirit was a very early Peterson one tonner that was 4th in the One Ton Nationals in about 1975, and then owned by Milt and Marty Vogel for several years. I raced that boat both with the "B" section and later with a modern section (way better).

The G4 section in the paper, as used on Courageous, has the characteristics we commonly see in high performance masts today: a flat front, with "knuckles" where the curvature increases, and then flatter sides. This was soon shown to be nearly as good as the "vortex generators" without destroying sails or people going up the mast.

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Bob Barton isn’t a name you hear much! I worked for him at Horizon in the mid eighties. Very bright guy and an excellent sailer. The B&R rigs had hydraulic head and back stays for what, 1 or 2 years before they became illegal. The rig could rock In either direction.

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2 hours ago, carcrash said:

The vortex generators are too far aft on this rig. Clearly, they might have been aeronautical engineers, but they did not do their due diligence in reading the technical papers of the day.

Here is the paper they should have read. I did. In fact, I was in the audience at the AIAA Aero/Hydronautics of Sailing conference when Gentry presented this paper. He brought along the wind tunnel test articles shown in pictures in the paper.

http://gentrysailing.com/pdf-theory/Studies-of-Mast-Section-Aerodynamics.pdf

"This is because the peak-velocity point on the mast is always forward of the maximum width point ... the boundary layer is tripped to turbulent, the flow will separate at the peak velocity point."

Therefore, the boundary layer has already tripped BEFORE getting to the vortex generators. Hence, the vortex generators in the above picture were simply weight aloft.

"If the boundary layer could be made to trip from the laminar state to the turbulent state before the peak velocity is reached, then it would stay attached longer."

The peak velocity is roughly where the mast is thickest when looking at it from the apparent wind, 30 degrees to the side. Not from directly ahead. Hence, the strips needed to be forward about two or three widths of those rivet-strips to have any aero effect.

If anyone actually reads that paper, on page 6 there is a section called "B" that was used on Kindred Spirit, originally owned by Bob Barton (perhaps hence the "B"). Kindred Spirit was a very early Peterson one tonner that was 4th in the One Ton Nationals in about 1975, and then owned by Milt and Marty Vogel for several years. I raced that boat both with the "B" section and later with a modern section (way better).

The G4 section in the paper, as used on Courageous, has the characteristics we commonly see in high performance masts today: a flat front, with "knuckles" where the curvature increases, and then flatter sides. This was soon shown to be nearly as good as the "vortex generators" without destroying sails or people going up the mast.

There is also a good section on this in Ross Garrett's book " The Symmetry of Sailing".  An excellent read BTW.

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13 hours ago, cms said:

Diva was built for Bernard Moureau by Hervé in la Rochelle. She was a genuine breakthrough boat, opening the way for the wave of one tonners that followed from Andrieu, Briand, Judel/Vrolijk and eventually most designers.

Bernard Moureau is one to be remembered amongst the French racing owners.

Multiple boats owner ( I remember a Belmore derivative, a Monk of Malham sistership, two hot half tonners, The flush-deck First 42, Diva, Espace du Desir,  and others I've forgotten). he could be seen on many RORC starting lines or the odd Bermuda Race and, of course, Ton cups too.

 

 

 

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9 hours ago, Sail12m said:

Bob Barton isn’t a name you hear much! I worked for him at Horizon in the mid eighties. Very bright guy and an excellent sailer. The B&R rigs had hydraulic head and back stays for what, 1 or 2 years before they became illegal. The rig could rock In either direction.

His brother is a very talented sailor too....Bill

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9 hours ago, carcrash said:

The vortex generators are too far aft on this rig. Clearly, they might have been aeronautical engineers, but they did not do their due diligence in reading the technical papers of the day.

Here is the paper they should have read. I did. In fact, I was in the audience at the AIAA Aero/Hydronautics of Sailing conference when Gentry presented this paper. He brought along the wind tunnel test articles shown in pictures in the paper.

http://gentrysailing.com/pdf-theory/Studies-of-Mast-Section-Aerodynamics.pdf

"This is because the peak-velocity point on the mast is always forward of the maximum width point ... the boundary layer is tripped to turbulent, the flow will separate at the peak velocity point."

Therefore, the boundary layer has already tripped BEFORE getting to the vortex generators. Hence, the vortex generators in the above picture were simply weight aloft.

"If the boundary layer could be made to trip from the laminar state to the turbulent state before the peak velocity is reached, then it would stay attached longer."

The peak velocity is roughly where the mast is thickest when looking at it from the apparent wind, 30 degrees to the side. Not from directly ahead. Hence, the strips needed to be forward about two or three widths of those rivet-strips to have any aero effect.

If anyone actually reads that paper, on page 6 there is a section called "B" that was used on Kindred Spirit, originally owned by Bob Barton (perhaps hence the "B"). Kindred Spirit was a very early Peterson one tonner that was 4th in the One Ton Nationals in about 1975, and then owned by Milt and Marty Vogel for several years. I raced that boat both with the "B" section and later with a modern section (way better).

The G4 section in the paper, as used on Courageous, has the characteristics we commonly see in high performance masts today: a flat front, with "knuckles" where the curvature increases, and then flatter sides. This was soon shown to be nearly as good as the "vortex generators" without destroying sails or people going up the mast.

the spar extrusion had a sight relief to accept the vortex generator tape thickness, so the placement is precisely where the wind tunnel conclusion called for them to be...that said they were about as effective as keel trim tabs......theoretical but impossible to experience results  when in use

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9 hours ago, Sail12m said:

Bob Barton isn’t a name you hear much! I worked for him at Horizon in the mid eighties. Very bright guy and an excellent sailer. The B&R rigs had hydraulic head and back stays for what, 1 or 2 years before they became illegal. The rig could rock In either direction.

"Kindred Spirit" one tonner

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On 4/10/2020 at 8:53 AM, SF Woody Sailor said:

Corollary question: I have been thinking about picking up a second hand blooper for my boat (36 footer). Would I be able to find any bowmen or bowchicks in the SF Bay area who know how to buoy race a blooper? Or are they extinct?

War Dog. Or me.

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2 minutes ago, P_Wop said:

Me too.  A blooper gybe right outside the StFYC is a thing of beauty for the spectators on the roof.  Unless it's not.

Theire our to tipes of sailores oute theire, thoise thet no howe to gybe and thoise thet do notte...........               :)

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29 minutes ago, P_Wop said:

Me too.  A blooper gybe right outside the StFYC is a thing of beauty for the spectators on the roof.  Unless it's not.

That is one you don't want to fuck up nowadays when every spectator has a camera.

I would prefer not to repeat this experience of gybing right in front of the St.FYC during BBS. 

 

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A pic from my early days...

That’s me in the after guard spot. Decision - Serendipity 43 (Peterson) built at Palmer Johnson. Dave Howell was the owner. This would have been ‘84 the year of my first Chi-Mac. By the end of 85 was doing foredeck full time. Still love the older boats... Got myself an ‘83 J/29 now. Not an IOR boat but an oldie but a goodie.

AE5702DE-CD12-4F40-93C5-4DC337B743B9.jpeg

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29 minutes ago, Rhumb Runner said:

A pic from my early days...

That’s me in the after guard spot. Decision - Serendipity 43 (Peterson) built at Palmer Johnson. Dave Howell was the owner. This would have been ‘84 the year of my first Chi-Mac. By the end of 85 was doing foredeck full time. Still love the older boats... Got myself an ‘83 J/29 now. Not an IOR boat but an oldie but a goodie.

AE5702DE-CD12-4F40-93C5-4DC337B743B9.jpeg

Great times,  smiling faces racing against the likes of Vagary, Whiplash, and other notables during those days long ago, in a galaxy far far away.

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2 hours ago, P_Wop said:

Me too.  A blooper gybe right outside the StFYC is a thing of beauty for the spectators on the roof.  Unless it's not.

Oh I don't know-from the Race Deck at the Frantic the wipeouts are pretty enjoyable too 

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Heh.  I remember one BBS I was doing bow on Native Son, and the whole romping reach across from Sausalito the guys in fantasy-land couldn't decide between a bear-away or a gibe-set at the mark in front of StFYC.  After changing their minds a few times, and me changing all the gear over each time, I finally called an audible and sat in the bow pulpit for the last 5 boatlengths or so with the bag in my lap and all the corners hooked up. 

When the bow passed the mark, I yelled "HOIST", threw a couple of armsfull of cloth up in the air, and ducked.  Had just enough time to think "this is either going to be really good or really bad".

It turned out really good.  Chute went straight up, filled with a "woooomf" before the stern cleared the mark, and I had a chance to admire it for a second before dawdling off the bow and hooking whichever guy turned out to be the right one into the pole on my way back to the mast.   Heard there was video of it but never saw it.  I just smiled as if it was just another day at the office.

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1 hour ago, Geff said:

Great times,  smiling faces racing against the likes of Vagary, Whiplash, and other notables during those days long ago, in a galaxy far far away.

 

2 hours ago, Rhumb Runner said:

A pic from my early days...

That’s me in the after guard spot. Decision - Serendipity 43 (Peterson) built at Palmer Johnson. Dave Howell was the owner. This would have been ‘84 the year of my first Chi-Mac. By the end of 85 was doing foredeck full time. Still love the older boats... Got myself an ‘83 J/29 now. Not an IOR boat but an oldie but a goodie.

AE5702DE-CD12-4F40-93C5-4DC337B743B9.jpeg

Man, amazing driving to get her nose down, did you recover from that mishap?  Remember the really good IOR drivers could keep the boat under the kite until the bow buried and slam bam the the boat snapped over to one side or the other.

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On 4/14/2020 at 3:28 PM, Tom O'Keefe said:

Awe come on...most of us made it. A bit scarred and war torn. But, we made it.

Perhaps time for Dry Armour to hear up for another production run?

 

post-1196-0-85038000-1479939937.jpg

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Just now, SF Woody Sailor said:

WTF?

This was an peculiar interpretation of the IOR, designed and built for the 1/2-ton world championship in 1983, in Hankø, Norway. Named Halving. Designed på famous Jan Herman Linge, it didn’t qualify.

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15 hours ago, Rhumb Runner said:

A pic from my early days...

That’s me in the after guard spot. Decision - Serendipity 43 (Peterson) built at Palmer Johnson. Dave Howell was the owner. This would have been ‘84 the year of my first Chi-Mac. By the end of 85 was doing foredeck full time. Still love the older boats... Got myself an ‘83 J/29 now. Not an IOR boat but an oldie but a goodie.

AE5702DE-CD12-4F40-93C5-4DC337B743B9.jpeg

Dave Howell was one of several skippers responsible for making me the sailor I am today. My first salty ocean race was an SORC aboard his PJ 37 one tonner.

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Not my cup of tea but I actually applaud the owner and designer for pushing the envelope ....why to I keep thinking of the owners wife ...LOL...

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38 minutes ago, SloopJonB said:

Really dumb idea.

Experimental aircraft have been built with forward swept wings to create dynamic instability so the computers could fly an incredibly twitchy aircraft.

image.png.062ff1262971e379c336f52115016cb9.png

https://en.wikipedia.org/wiki/Grumman_X-29

The only dumb idea on that keel is the bulb on an IOR half ton.  Bulbs did not work under IOR - plus the fact that one has a really shitty bulb shape.

The forward swept foil is a good idea for several reasons:

- It generates inward spanwise flow which (in the absence of a bulb) reduces induced drag

- It tends to induce twist at the tip which generates more lift (although danger of stalling in aircraft)

- Moving the leading edge of the keel root aft of the point of maximum sectional area tends to reduce interference drag as it eliminates the "hump" a keel usually adds to the area curve (this is why racing boat designers like to have very thin short chord foil roots - to minimize the "hump").

I built a paper airplane years ago with forward swept wings (not totally folded, some cutting, taping and a paper clip for balance) People who saw it didn't believe it would fly but it flew further and straighter than any other one I ever came up with.  It looked a lot like a paper version of the X-29 but without the canards.

Of course kelp catching is a huge drawback if you sail in such an area.

 

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1 hour ago, 12 metre said:

- It tends to induce twist at the tip which generates more lift (although danger of stalling in aircraft)

 

 

It's going to twist the keel fin the wrong way to create lift.

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1 hour ago, A3A said:

It's going to twist the keel fin the wrong way to create lift.

Nope.  Aerodynamically a forward swept wing is superior especially at low speeds - structurally however it is a nightmare for aircraft due to the amount of lift and torsional loads it can generate

Below I copied and pasted from an aircraft modelling site: 

Forward Sweep and “Aeroelastic tailoring”

Air flowing over any swept wing tends to move spanwise towards the rearmost end of the wing. On a conventional rearward-swept wing, this is outwards towards the tip. But in a forward-swept wing, it is inwards towards the root. As a result, the dangerous tip stall condition of a backwards-swept design becomes a safer and more controllable root stall on a forward swept design. This allows full aileron control despite loss of lift and also means that drag-inducing leading edge slots or other devices are not required.

With the air flowing inwards, wingtip vortices and the accompanying drag are reduced, instead the fuselage acts as a very large wing fence and, since wings are generally larger at the root, this improves lift allowing a smaller wing. As a result maneuverability is improved, especially at high angles of attack

These were some of advantages which make the forward sweep look as a very attractive choice. However, the aeroelastic divergence issues made it uncommon. In a forward swept wing configuration, the aerodynamic lift produces a twisting force which rotates the wing leading edge upward. This will result in a higher angle of attack, which increases lift, twisting the wing further. This aeroelastic divergence can quickly lead to structural failure. With conventional metallic construction, a torsionally very stiff wing would be required to resist twisting; stiffening the wing adds weight, which may make the design unfeasible. But X-29 and Su 47 designs made use of Aeroelastic tailoring in which the anisotropic elastic coupling between bending and twisting of the carbon fiber composite material to address this aeroelastic effect. Rather than using a very stiff wing, which would carry a weight penalty, these planes used laminates which produced coupling between bending and torsion. As lift increases, bending loads force the wing tips to bend upward. Torsion loads attempt to twist the wing to higher angles of attack, but the coupling resists the loads, twisting the leading edge downward reducing wing angle of attack and lift. With lift reduced, the loads are reduced and divergence is avoided

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1 hour ago, Laker said:

Ask yourself why the later 12 meter (82 and 87) keels had such a shape. Nose was forward of the root.  It works.

 True, but those were more inverted or "upside down" keels.  They had minimal if any sweep in either direction.

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22 minutes ago, 12 metre said:

Nope.  Aerodynamically a forward swept wing is superior especially at low speeds - structurally however it is a nightmare for aircraft due to the amount of lift and torsional loads it can generate

Below I copied and pasted from an aircraft modelling site: 

Forward Sweep and “Aeroelastic tailoring”

Air flowing over any swept wing tends to move spanwise towards the rearmost end of the wing. On a conventional rearward-swept wing, this is outwards towards the tip. But in a forward-swept wing, it is inwards towards the root. As a result, the dangerous tip stall condition of a backwards-swept design becomes a safer and more controllable root stall on a forward swept design. This allows full aileron control despite loss of lift and also means that drag-inducing leading edge slots or other devices are not required.

With the air flowing inwards, wingtip vortices and the accompanying drag are reduced, instead the fuselage acts as a very large wing fence and, since wings are generally larger at the root, this improves lift allowing a smaller wing. As a result maneuverability is improved, especially at high angles of attack

These were some of advantages which make the forward sweep look as a very attractive choice. However, the aeroelastic divergence issues made it uncommon. In a forward swept wing configuration, the aerodynamic lift produces a twisting force which rotates the wing leading edge upward. This will result in a higher angle of attack, which increases lift, twisting the wing further. This aeroelastic divergence can quickly lead to structural failure. With conventional metallic construction, a torsionally very stiff wing would be required to resist twisting; stiffening the wing adds weight, which may make the design unfeasible. But X-29 and Su 47 designs made use of Aeroelastic tailoring in which the anisotropic elastic coupling between bending and twisting of the carbon fiber composite material to address this aeroelastic effect. Rather than using a very stiff wing, which would carry a weight penalty, these planes used laminates which produced coupling between bending and torsion. As lift increases, bending loads force the wing tips to bend upward. Torsion loads attempt to twist the wing to higher angles of attack, but the coupling resists the loads, twisting the leading edge downward reducing wing angle of attack and lift. With lift reduced, the loads are reduced and divergence is avoided

Most interesting explanation 

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1 hour ago, P_Wop said:

Nestled down in the half ounce runner and waiting....

I always appreciated it when the owner brought along the pilot-berth cushions.  Arranged just right on the cabin sole, they made a nice comfy little play-pen

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22 hours ago, BravoBravo said:

Well not well known...probably for the obvious 

 

ior2.jpg

iorr.jpg

Need a thread dedicated to weird ass boats or "innovative" interpretation of the rules.  It would be very interesting.  Looks like it was cruisified.

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22 minutes ago, some dude said:

Bingo sighting!

Heh.  You can always tell a boat that Dennis Choate built for his own use by the sail number.  It always reduces to an "8" (2+8+8+8 = 17, 1+7 = 8)

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