89er

JulianB

Super Anarchist
1,162
1,550
Sydney mostly
How I work out how much area I need to plane efficiently, call it a coef. if you wish, is to look at the horizontal or near horizontal surface area and come up with a kgs/m² number.

I'm guessing this is what you are alluding to WRT CP's.

Most speed boat run around at 25° dead-rise, but they use tunnels and strakes which are not so fast on a boat that is predominantly going to be doing HS.

I dis-regard anything with a deadrise of greater than 25-30° and heavily discount, based on Sin, anything under 25°.    But you have to factor it up, because empirically doing say 12knts when you start to come out (to a significant degree) even at 20-25° the water will simply move sideways (without strakes or tunnels to constrain it) so it's lifting potential is not that great.   Very much a fudge factor.   By the time you’re doing 20knts front ½ of the boat is well out of the water, so what angle it is irrelevant except when you plunge, and then you want it to be fine, so you don't baulk/slam.

That’s my process, so this boat (89er) is thinner than say Vivace because a) it’s longer, so ipso factor it has more surface area (due to length) so it dose not need to be as wide and b) it’s likely to be able to travel at a higher quasi displacement speed with a smaller negative effect, than Vivace (due to length) so it can be opted for a higher “take off speed” (as in full planning.)

~~~~~~~~~~~~~~~~~~~~

Re the Thai Starboard company, they do really nice Windsurfers and i-Foilers and are very techy.

They would have to re-invent themselves to be the next breakout boat, because, sure a lot of people like and love windsurfing. The number of sails that are still being made each year is staggering and even in those days when people where very prematurely calling time on windsurfing, 40-50,000 sails where being pumped out of the big makers per year and still are.

If that’s death of a sector, then that’s a great way to die!

So I doubt Starboard will be the one, and I think they are Dutch, that is not a problem but they are not Asian.   Lessons learned when you are young are very hard to un-do.

Fully immersing yourself in the culture helps, but unlikely to wipe it out, nor would you wish it to, completely.

 

Sidecar

…………………………
3,115
1,487
Tasmania
How I work out how much area I need to plane efficiently, call it a coef. if you wish, is to look at the horizontal or near horizontal surface area and come up with a kgs/m² number.

I'm guessing this is what you are alluding to WRT CP's.
So what is your magic number? And at what speed? Do you factor in leading edge width, angles or perimeter? You hinted at (bow wave?) angles? Mine is ~ 290 kg/m2 without any modifying factors.

Prismatic coefficients have little to do directly with planing, they are an indication of the displacement volume distribution, or fineness of the ends. Your stern sections don’t look fine on plan, but they are in profile. A higher Cp can help to shift HS up from 1.34*LWL^0.5 to a better number off wind for more conventional boats. Hard on the wind, a higher Cp usually means a slower max HS, especially in chop. Having a Cp of, say, ~ 0.7 won’t necessarily guarantee that a boat can plane early or even at all, but would pretty well guarantee that it will be a dog upwind.

Traditionally, HS > 2.0*LWL^0.5 was regarded as planing. That equates to ~ 10.8 knots for the 89’er. So if you say the 89’er target speed is ~ 8 -9 knots upwind, then clearly it won’t be planing, especially if by your own rules of thumb, you need an SCP of< 4.0 and the 89’er has > 6.0.

 
A

Amati

Guest
How I work out how much area I need to plane efficiently, call it a coef. if you wish, is to look at the horizontal or near horizontal surface area and come up with a kgs/m² number.

I'm guessing this is what you are alluding to WRT CP's.

Most speed boat run around at 25° dead-rise, but they use tunnels and strakes which are not so fast on a boat that is predominantly going to be doing HS.

I dis-regard anything with a deadrise of greater than 25-30° and heavily discount, based on Sin, anything under 25°.    But you have to factor it up, because empirically doing say 12knts when you start to come out (to a significant degree) even at 20-25° the water will simply move sideways (without strakes or tunnels to constrain it) so it's lifting potential is not that great.   Very much a fudge factor.   By the time you’re doing 20knts front ½ of the boat is well out of the water, so what angle it is irrelevant except when you plunge, and then you want it to be fine, so you don't baulk/slam.

That’s my process, so this boat (89er) is thinner than say Vivace because a) it’s longer, so ipso factor it has more surface area (due to length) so it dose not need to be as wide and b) it’s likely to be able to travel at a higher quasi displacement speed with a smaller negative effect, than Vivace (due to length) so it can be opted for a higher “take off speed” (as in full planning.)

~~~~~~~~~~~~~~~~~~~~

Re the Thai Starboard company, they do really nice Windsurfers and i-Foilers and are very techy.

They would have to re-invent themselves to be the next breakout boat, because, sure a lot of people like and love windsurfing. The number of sails that are still being made each year is staggering and even in those days when people where very prematurely calling time on windsurfing, 40-50,000 sails where being pumped out of the big makers per year and still are.

If that’s death of a sector, then that’s a great way to die!

So I doubt Starboard will be the one, and I think they are Dutch, that is not a problem but they are not Asian.   Lessons learned when you are young are very hard to un-do.

Fully immersing yourself in the culture helps, but unlikely to wipe it out, nor would you wish it to, completely.
Does an Asian breakout boat jettison historical/cultural baggage?  Or, for lack of a better term, redefine it?  I’d argue the Laser redefined the western sense, without jettisoning it.  But, say, looking at what China (and some other countries in the region) has done in the last few decades with architecture, that might argue for the former (jettison) as an ‘Asian’ state of mind as far as new stuff is concerned. If that new architecture expresses ‘we will make the west look like an antique’, that would go along with bringing in western designers for buildings and cars, which might mean more the Starboard model.  But if the Asian sailing zeitgeist is looking for something different than western skiffs, Oceania might serve? Western tech and cultural expression is kind of a sliding scale anyway.  And I’d argue it could hinge on scows, at least at the mainland Asian end of things
 

Jim Antrim design for Barry Spanier-

http://antrimdesign.com/rosie.html

33FE1C8D-5D90-4E85-AA7D-3EC57E02EDAB.jpeg

 
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A

Amati

Guest
So what is your magic number? And at what speed? Do you factor in leading edge width, angles or perimeter? You hinted at (bow wave?) angles? Mine is ~ 290 kg/m2 without any modifying factors.

Prismatic coefficients have little to do directly with planing, they are an indication of the displacement volume distribution, or fineness of the ends. Your stern sections don’t look fine on plan, but they are in profile. A higher Cp can help to shift HS up from 1.34*LWL^0.5 to a better number off wind for more conventional boats. Hard on the wind, a higher Cp usually means a slower max HS, especially in chop. Having a Cp of, say, ~ 0.7 won’t necessarily guarantee that a boat can plane early or even at all, but would pretty well guarantee that it will be a dog upwind.

Traditionally, HS > 2.0*LWL^0.5 was regarded as planing. That equates to ~ 10.8 knots for the 89’er. So if you say the 89’er target speed is ~ 8 -9 knots upwind, then clearly it won’t be planing, especially if by your own rules of thumb, you need an SCP of< 4.0 and the 89’er has > 6.0.
So 60 pounds / sq foot?  This gets rapidly into the incredibly fun world of surfboard shaping - displacement logs on one end to Simmons/Lord hulls on the other end. There is a good story of a couple of guys being towed behind a motorboat on their logs and things get really bogged down as the motorboat accelerates.  So the guys step forward, ride the nose and off they go! (This sounds familiar  :lol: ).  And the infinity of shapes between. Lindsay Lord liked .3 to .5 length to beam, but I’d have to look up what he thought about loading.  There’s a pic in this link of a rum runner of the 30’s that looks interesting:

https://infoamed.com/2020/09/12/revisionist-history-did-tom-morey-really-invent-the-bodyboard-design/

 
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A

Amati

Guest
Nice look at one of Simmons longboards-  he really keeps the nose up at speed in the Vimeo 

https://player.vimeo.com/video/15614315?h=189f06a572&app_id=122963

If you take the loading of the back end of the boat when planing as 220 lbs, and the board is planing on 4’ (?), and it’s 2’ wide, that’s a loading of 27.5 lbs/ sq ft, Lord aspect ratio of .5, which starts to look like an early formula board, before the conclaves started appearing.  Double fins.

 
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JulianB

Super Anarchist
1,162
1,550
Sydney mostly
Re Asia and where they may go.

We all sit here and think that we (the West) are the only ones who have built boats and are the bastions of all knowledge.

It ain't so.   Some of the sailing families I am aware of in parts of Asia, their sailing line goes back 1000's of years, and you need to only look at what they could do and the size of their armada's and seamanship long before Magellan was in nappies.  The Indian's and the Chinese, my god, so advanced, and then the first mass seabourne migration was the Aborigines long before even the Egyptians.   40,000 years ago.

Anyway, I think that American marketing post the war, very clever way of controlling a population, embodied what was "good", in terms of image.   Not sure that all of that has sunk in, especially when you get away from the big hubs, so what you will start to see in Asia is the awakening of their image, rather than ours.

For instance, the Topper, fine bit of British engineering, spearheaded by a British ex-Topper class president, who happened to be seconded to China, so China brought 2-3,000 of them 15 years ago.   Don't think they have brought any more, and highly unlikely they will buy any more or RS or Bic or anything like that.

They are becoming far more pragmatic, just because it's "good" in Europe or US dose not mean it will be good in Asia.    And South America is similar.

The Starboards, or the Element6 will have a influence, Element6 more so because of the fluency of the staff in multiple Asian languages (I'm talking the British and American owners) and the ease of logistics with Thailand and the rest of Asia, but there will be a lot of home growth products out of every Asian country, and those products will be very cost effective.    China is the powerhouse, (but India will be very interesting) WRT Asia, just like Brazil is in South America, USA is in Nth America, and South Africa is/was in Sth Africa.

~~~~~~~~~~~~~~~~~~~~

With respect to lbs/ft-sq or in my case kgs/m-sq,

49er is about 119kgs/m-sq,   89er and Vivace are both close to 112kgs/m-sq, interestingly the 29er is up around 136kgs/m-sq and the 470 is way down around 77kgs/m-sq.    All of those numbers are fudges and I can do the 470, because I designed one some years back, so I have the files, no other reason.

This is at what I believe is standard break out attitude and speeds which vary because of changes in HS

But that is not the whole story, the other big factor is power to weight ratio, 29er is about 89%, 49er is 149%, 89er will be very close to 1 (100%, so same RM (kg/m) as weight) and a 470 is about 67%

so a 29er will stay in the water longer, and that is for 2 reasons, a) it's safer for the kids, it's not quite as frisky as say a 49er and b) it's quite possibly a better hull shape given what we know now.  (and it's higher panel loading is possibly why it can achieve higher speeds than a 49er), where as a 49er comes out early simply because it got so much grunt, it just blasts over its bow wave.   But the 89er, it's a displacement toy (80% of the time) and it has the advances of the 29er (hull design) so I expect to to stay in the water all the time upwind, but it also has lot's of potential grunt so I want it to come out effortlessly off the wind.

I do expect to occasionally (quite rarely) do mid 20's in the 89er but to design for that would be rather stupid, and it's possibly 0.001% of the time.   But, as said, it will have plenty of grunt, so I do want it to pop up on the plane effortlessly when we turn the corner at the top mark and play AWA's down hill.

The reality is that, sure I think we have advanced the shape, but Vivace was such a good role model, why wouldn't I just duplicate it's numbers (so I did)!

 
A

Amati

Guest
Re Asia and where they may go.

We all sit here and think that we (the West) are the only ones who have built boats and are the bastions of all knowledge.

It ain't so.   Some of the sailing families I am aware of in parts of Asia, their sailing line goes back 1000's of years, and you need to only look at what they could do and the size of their armada's and seamanship long before Magellan was in nappies.  The Indian's and the Chinese, my god, so advanced, and then the first mass seabourne migration was the Aborigines long before even the Egyptians.   40,000 years ago.

Anyway, I think that American marketing post the war, very clever way of controlling a population, embodied what was "good", in terms of image.   Not sure that all of that has sunk in, especially when you get away from the big hubs, so what you will start to see in Asia is the awakening of their image, rather than ours.

For instance, the Topper, fine bit of British engineering, spearheaded by a British ex-Topper class president, who happened to be seconded to China, so China brought 2-3,000 of them 15 years ago.   Don't think they have brought any more, and highly unlikely they will buy any more or RS or Bic or anything like that.

They are becoming far more pragmatic, just because it's "good" in Europe or US dose not mean it will be good in Asia.    And South America is similar.

The Starboards, or the Element6 will have a influence, Element6 more so because of the fluency of the staff in multiple Asian languages (I'm talking the British and American owners) and the ease of logistics with Thailand and the rest of Asia, but there will be a lot of home growth products out of every Asian country, and those products will be very cost effective.    China is the powerhouse, (but India will be very interesting) WRT Asia, just like Brazil is in South America, USA is in Nth America, and South Africa is/was in Sth Africa.

~~~~~~~~~~~~~~~~~~~~

With respect to lbs/ft-sq or in my case kgs/m-sq,

49er is about 119kgs/m-sq,   89er and Vivace are both close to 112kgs/m-sq, interestingly the 29er is up around 136kgs/m-sq and the 470 is way down around 77kgs/m-sq.    All of those numbers are fudges and I can do the 470, because I designed one some years back, so I have the files, no other reason.

This is at what I believe is standard break out attitude and speeds which vary because of changes in HS

But that is not the whole story, the other big factor is power to weight ratio, 29er is about 89%, 49er is 149%, 89er will be very close to 1 (100%, so same RM (kg/m) as weight) and a 470 is about 67%

so a 29er will stay in the water longer, and that is for 2 reasons, a) it's safer for the kids, it's not quite as frisky as say a 49er and b) it's quite possibly a better hull shape given what we know now.  (and it's higher panel loading is possibly why it can achieve higher speeds than a 49er), where as a 49er comes out early simply because it got so much grunt, it just blasts over its bow wave.   But the 89er, it's a displacement toy (80% of the time) and it has the advances of the 29er (hull design) so I expect to to stay in the water all the time upwind, but it also has lot's of potential grunt so I want it to come out effortlessly off the wind.

I do expect to occasionally (quite rarely) do mid 20's in the 89er but to design for that would be rather stupid, and it's possibly 0.001% of the time.   But, as said, it will have plenty of grunt, so I do want it to pop up on the plane effortlessly when we turn the corner at the top mark and play AWA's down hill.

The reality is that, sure I think we have advanced the shape, but Vivace was such a good role model, why wouldn't I just duplicate it's numbers (so I did)!
Cultural blindness isn’t exactly an American fiefdom, but we have had our moments.  The archeology and anthropology of sailing are invaluable, but while trying to overcome the inertia of cultural palm gazing is an almost impossible task, some enlightenment (or reality) oozes around the edges.  I started in the American piano industry in the 60’s, and witnessed first hand it’s stubborn self destruction- going from 100’s of vibrant companies to 2 or 3.  I also watched and represented technically and artistically 15 brands from around the world, and watched the flourishing of different approaches of craft influencing mechanization based on a discarded (here) American industrial concept (Demming). It has come full circle (kind of) back here, but the same forces that make it impossible to deal with COVID here have been at work in so many endeavors that rational creativity has been drowned by the shouting.  Thank God, in sailing, some of us live on the West Coast, and have embraced Oceania and run with it, Like Hobie Alter, for example, along with Windsurfing, surfing, kayaking, surf skis, SUP’s etc.  Whether mass industrialization is the path forward is kind of up in the air, I think, and Yamaha buying into Bosendorfer may fit into that scenario, as well as the Clark foam implosion,  as the bespoke movement chugs along.  Personally, I believe nimble small to medium production is the future.  Man made products along with more green, like wood.  Like right now, I have a handmade German wood cello, a Czechoslovakian electric cello, an American electric, and an American carbon cello. These three approaches are all starting to combine.  Same in pianos.  And culturally idiosyncratic pianos are once again peeking out around the world- Australia is a good example.  While the mass manufacturers thunder along, gobbling each other up.  So, as you imply, regional markets may be the future, with some leakage globally among those with some curiosity.  Will the basic scientific principles survive?  It’s starting to fray here, big time. Lord, in his book that I posted deals with that inertia, which is wonderful, much as your dad did.

My personal Big Question is whether the effect of rules (which are in their nature cultural)  on sailboats is stifling things, or defining progress.  The power of limits is a real thing, and the next big thing could be the result of a different rule, from a different point of view.  But, was the Laser the product of a rule?  Windsurfing? Kiting? Sportsboats? Multihulls? 49er? It gets back to the fundamental logic of Demming’s idea of production in many ways, and the way it fits into a culture.  

 
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Sidecar

…………………………
3,115
1,487
Tasmania
But that is not the whole story, the other big factor is power to weight ratio, 29er is about 89%, 49er is 149%, 89er will be very close to 1 (100%, so same RM (kg/m) as weight) and a 470 is about 67%

so a 29er will stay in the water longer, and that is for 2 reasons, a) it's safer for the kids, it's not quite as frisky as say a 49er and b) it's quite possibly a better hull shape given what we know now.  (and it's higher panel loading is possibly why it can achieve higher speeds than a 49er), where as a 49er comes out early simply because it got so much grunt, it just blasts over its bow wave.   But the 89er, it's a displacement toy (80% of the time) and it has the advances of the 29er (hull design) so I expect to to stay in the water all the time upwind, but it also has lot's of potential grunt so I want it to come out effortlessly off the wind.
So to be clear, power to weight ratio is: RM/ Displ.

Waterline beam (lifting edge) relative to length is also a big factor in facilitating planing. Just guessing, but the 29’er and 49’er both would have a B/L length of ~ 33%, and the 89’er would be ~ 24%? Interestingly, the Lindsay Lord literature above suggests that the practical sweet spot for planing boats is ~ 35 to 40%, with a big drop off in efficiency, as the %age goes down, certainly below 20%.

FWIW, He also says that you can be under loaded panel wise and still be not as fast as a boat with higher panel loads, because of loss of control.

 
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A

Amati

Guest
So to be clear, power to weight ratio is: RM/ Displ.

Waterline beam (lifting edge) relative to length is also a big factor in facilitating planing. Just guessing, but the 29’er and 49’er both would have a B/L length of ~ 33%, and the 89’er would be ~ 24%? Interestingly, the Lindsay Lord literature above suggests that the practical sweet spot for planing boats is ~ 35 to 40%, with a big drop off in efficiency, as the %age goes down, certainly below 20%.

FWIW, He also says that you can be under loaded panel wise and still be not as fast as a boat with higher panel loads, because of loss of control.
Which could be one reason some proa cultures used a solid log for the small hull?  

 
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A

Amati

Guest
So to be clear, power to weight ratio is: RM/ Displ.

Waterline beam (lifting edge) relative to length is also a big factor in facilitating planing. Just guessing, but the 29’er and 49’er both would have a B/L length of ~ 33%, and the 89’er would be ~ 24%? Interestingly, the Lindsay Lord literature above suggests that the practical sweet spot for planing boats is ~ 35 to 40%, with a big drop off in efficiency, as the %age goes down, certainly below 20%.

FWIW, He also says that you can be under loaded panel wise and still be not as fast as a boat with higher panel loads, because of loss of control.
This is fun. So, quick and dirty numbers for Amati

Loading somewhere between 44-52 lbs/sq ft (214- 253 kg/m squared? So I’m under your magic number)), beam/ length .25 - .27.  I don’t know if dynamic length means anything in this context.  I do know when I stand on the bow, the stern flow gets real smooooth

 We do have a rooster tail. Aaack!

This puts us at the low end of loading in Lindsay Lord land, but in the ball park.  We reached our top speed (22 k) in a 3-4 foot chop, which Lord would predict. Downwind we do not go airborne, and control is not a problem.  Once we hit about 11 knots she gets more stable as we go faster. And she’s really close winded- like a meter boat.  Maybe that’s the trade off?  The only time she jumps is when we’re going upwind in more than 10 knots in lumpy stuff.

Our bow stays close to the water.  Looks like I wanted a cruising sled & I got one!

I’ll try to figure the leverage later.

 
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JulianB

Super Anarchist
1,162
1,550
Sydney mostly
Cultural blindness isn’t exactly an American fiefdom, but we have had our moments.  The archeology and anthropology of sailing are invaluable, but while trying to overcome the inertia of cultural palm gazing is an almost impossible task, some enlightenment (or reality) oozes around the edges.  I started in the American piano industry in the 60’s, and witnessed first hand it’s stubborn self destruction- going from 100’s of vibrant companies to 2 or 3.  I also watched and represented technically and artistically 15 brands from around the world, and watched the flourishing of different approaches of craft influencing mechanization based on a discarded (here) American industrial concept (Demming). It has come full circle (kind of) back here, but the same forces that make it impossible to deal with COVID here have been at work in so many endeavors that rational creativity has been drowned by the shouting.  Thank God, in sailing, some of us live on the West Coast, and have embraced Oceania and run with it, Like Hobie Alter, for example, along with Windsurfing, surfing, kayaking, surf skis, SUP’s etc.  Whether mass industrialization is the path forward is kind of up in the air, I think, and Yamaha buying into Bosendorfer may fit into that scenario, as well as the Clark foam implosion,  as the bespoke movement chugs along.  Personally, I believe nimble small to medium production is the future.  Man made products along with more green, like wood.  Like right now, I have a handmade German wood cello, a Czechoslovakian electric cello, an American electric, and an American carbon cello. These three approaches are all starting to combine.  Same in pianos.  And culturally idiosyncratic pianos are once again peeking out around the world- Australia is a good example.  While the mass manufacturers thunder along, gobbling each other up.  So, as you imply, regional markets may be the future, with some leakage globally among those with some curiosity.  Will the basic scientific principles survive?  It’s starting to fray here, big time. Lord, in his book that I posted deals with that inertia, which is wonderful, much as your dad did.

My personal Big Question is whether the effect of rules (which are in their nature cultural)  on sailboats is stifling things, or defining progress.  The power of limits is a real thing, and the next big thing could be the result of a different rule, from a different point of view.  But, was the Laser the product of a rule?  Windsurfing? Kiting? Sportsboats? Multihulls? 49er? It gets back to the fundamental logic of Demming’s idea of production in many ways, and the way it fits into a culture.  
So I thought the demise of the light aircraft industry was due to litigation in the US??????

I have flown lots of light (power) planes but my passion was gliding, and I love my time soaring, but in some ways I have ticked that off, very likely prematurely.

This is very off thread, so you comments re cello out of wood and Carbon need so time to process.

You comments re rules, that could be a whole additional string, but let me ponder both and come back to you with my ideas, for what it's worth!

                jB

 

JulianB

Super Anarchist
1,162
1,550
Sydney mostly
So to be clear, power to weight ratio is: RM/ Displ.

Waterline beam (lifting edge) relative to length is also a big factor in facilitating planing. Just guessing, but the 29’er and 49’er both would have a B/L length of ~ 33%, and the 89’er would be ~ 24%? Interestingly, the Lindsay Lord literature above suggests that the practical sweet spot for planing boats is ~ 35 to 40%, with a big drop off in efficiency, as the %age goes down, certainly below 20%.

FWIW, He also says that you can be under loaded panel wise and still be not as fast as a boat with higher panel loads, because of loss of control.
Have never looked at this, but let me do so and come back to you probably tomorrow, my beer can racing day!  (day off)

 
A

Amati

Guest
So I thought the demise of the light aircraft industry was due to litigation in the US??????

I have flown lots of light (power) planes but my passion was gliding, and I love my time soaring, but in some ways I have ticked that off, very likely prematurely.

This is very off thread, so you comments re cello out of wood and Carbon need so time to process.

You comments re rules, that could be a whole additional string, but let me ponder both and come back to you with my ideas, for what it's worth!

                jB
I get carried away by thinking people.

 
A

Amati

Guest
So to be clear, power to weight ratio is: RM/ Displ.

Waterline beam (lifting edge) relative to length is also a big factor in facilitating planing. Just guessing, but the 29’er and 49’er both would have a B/L length of ~ 33%, and the 89’er would be ~ 24%? Interestingly, the Lindsay Lord literature above suggests that the practical sweet spot for planing boats is ~ 35 to 40%, with a big drop off in efficiency, as the %age goes down, certainly below 20%.

FWIW, He also says that you can be under loaded panel wise and still be not as fast as a boat with higher panel loads, because of loss of control.
So at 1 degree, we’re .09%, and at 30 degrees we're 2.18.  

 

Sidecar

…………………………
3,115
1,487
Tasmania
 I don’t know if dynamic length means anything in this context.
It does.

For an indication of dynamic length try halving the length from bow to B w/l max and adding it to length aft of B w/max. Refer to  Figure 4 in the Lord literature. Which is where the long fine bows/entry on Julian’s boats could help, because for the same planing area, they “artificially” improve the B/L ratio, whist still being good in displacement mode. There are a few other subtle things about the ‘9’er boats, which get the tick from Lord as well.

But if your bow doesn’t lift, there is no reduction of frictional area which comes with planing.

 
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