Author Topic: Scientific Flatwater Board Testing 101  (Read 27463 times)

blueplanetsurf

  • Site Sponsor
  • Teahupoo Status
  • *****
  • Posts: 1896
  • Hawaii's SUP HQ
    • View Profile
    • Blue Planet Surf
Re: Scientific Flatwater Board Testing 101
« Reply #75 on: June 28, 2016, 01:54:09 AM »
Ok, so clearly there is a speed gap between the hull speed of a board, let's call it about 7 mph and planing speed which is supposedly above 12 mph. 
So if that in-between speed, above 8 mph but below 12 mph, that we are achieving during downwinders, where the board releases and drag is greatly reduced but the board is not fully planing, what do we call that? 
Sub-planing?  Really? 
I'll keep calling it planing because that's how it feels, even if it's not the scientifically correct term.

Robert Stehlik
Blue Planet Surf Shop, Honolulu
Hawaii's SUP HQ
http://www.blueplanetsurf.com

Chilly

  • Peahi Status
  • *****
  • Posts: 849
    • View Profile
    • Email
Re: Scientific Flatwater Board Testing 101
« Reply #76 on: June 28, 2016, 04:27:56 AM »
Ok, so clearly there is a speed gap between the hull speed of a board, let's call it about 7 mph and planing speed which is supposedly above 12 mph. 
So if that in-between speed, above 8 mph but below 12 mph, that we are achieving during downwinders, where the board releases and drag is greatly reduced but the board is not fully planing, what do we call that? 
Sub-planing?  Really? 
I'll keep calling it planing because that's how it feels, even if it's not the scientifically correct term.


As your board starts to lift and ride on top of the water, it is to some degree starting to plane. You can feel it. It happens in slick flatwater when you’re really pushing it or on a bump. To give it a hard number like 12 mph or scientific definition is pointless outside of a laboratory. So yes, I’m with you Robert.
NSP 2016 12'6 Surf Race Pro

DavidJohn

  • Cortez Bank Status
  • *****
  • Posts: 6675
    • View Profile
    • Email
Re: Scientific Flatwater Board Testing 101
« Reply #77 on: June 28, 2016, 05:22:09 AM »
I know that feeling and coming from a windsurfing background I'd not call it planing..

I think the word I'd use is surging or releasing without planing..

mrbig

  • Cortez Bank Status
  • *****
  • Posts: 2465
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #78 on: June 28, 2016, 07:04:24 AM »
I don't have a dog in this, ah, discussion but have been following it with great interest.

There is nothing new under the sun.

Check the archives right here:

www.standupzone.com/forum/index.php?topic=6605.0

Folks seemed a little less didactic with their opinions back then..
« Last Edit: June 28, 2016, 07:11:46 AM by mrbig »
Let it come to you..
SMIK 9'2" Hipster Mini Mal
SMIK 8'8" Short Mac Freo Rainbow Bridge
SMIK 8'4" Hipster Twin
King's 8'2" Accelerator SharkBoy

Bean

  • Cortez Bank Status
  • *****
  • Posts: 4211
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #79 on: June 28, 2016, 07:05:22 AM »
I'll keep calling it planing because that's how it feels, even if it's not the scientifically correct term.

+1

Also, it has become a term of art within the paddling community. For the last couple of years the pro's. Conor, Kai, etc. have used the term planing to describe board speeds above displacement speeds.   

I guess planing is like pornography, you know it when you see it. ;D

Eagle

  • Cortez Bank Status
  • *****
  • Posts: 2426
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #80 on: June 28, 2016, 09:34:43 AM »
These are quotes from the topic linked by mrbig a couple of posts earlier titled -> Planing Hull vs Displacement Hull?

DJ posted this in 2010 -

"I'm not into displacement hulls unless it's just for rivers or lakes with no real runners... If it's runners that you're into I think planing hulls are the way to go for sure.

For me it's all about getting on the plane and surfing the bumps and not just surging along in the way displacement hulls like to cruise.. even if they are faster.

DJ"

And PB posted this -

"Planing hulls look like surfboards, displacement hulls look like canoes."
Fast is FUN!   8)
Dominator - Touring Pintail - Bullet V2 - M14 - AS23

Eagle

  • Cortez Bank Status
  • *****
  • Posts: 2426
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #81 on: June 28, 2016, 12:00:41 PM »
Here are some comments about planing boards and sub-planing -

"Whereas the planing hull - the goal is to have the water go underneath the board and create lift.  So a planing hull will be faster to get on a plane and be faster once its released from the water and kind of gliding over the surface.  Which that kind of speed is only achievable if you have bumps that push you to get you up to that planing speed."

"sub-planing speeds"

https://youtu.be/Pe3UM0XNchY

And oh Robert - about 3:00 in your vid you use the term "sub-planing speeds" - so that's why it was put in quotes way back when.

But my perspective should be quite clear.  I am perfectly ok to call it gliding at 15 mph.  Or planing.  Or semi-planing.  Or whatever.

It is fun and gives a bit of a thrill - and that's what really counts to me and my friends when we DW -> and have a beer after.  We all talk about DW from a planing perspective - but those that cannot plane - do love the gliding aspect as well.  That is what pushes us to drop fat and put on muscle -> to plane like we see the pros doing.  Even if it is only for a second or two.  Pretty much all the guys that paddle with us are very fit lads - and very good DW paddlers and racers.  Many considerably better than me.  I am probably about mid-pack.  So very average.

As an aside - my wife loves gliding and getting pushed along by the waves when we head up to Squamish.  So the way I look at it - as long as you enjoy what you are doing and you're not hurting anyone - just do it.  That seems to our mentality anyways.  We just use normal common words and descriptors is all.  Glide - plane - surf - semi-plane - whatever.   :)
Fast is FUN!   8)
Dominator - Touring Pintail - Bullet V2 - M14 - AS23

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #82 on: June 28, 2016, 05:33:26 PM »
a. It's not speed that determines planing, well it does, if you have a planing hull, but NO--there are plenty of craft that don't plane that go very fast.

b. Planing is a specific term. Use it as you like, but that doesn't change what it is.

c. If you can see the bow wave in front of, you ain't planing. Period. You aren't semi planing any more than you are semi alive if you have a hangover.

d. Semi-planing is a bullshit marketing term, to describe hulls that can both plane but have displacement characteristics when they aren't. They don't beat your brains to jello at lower speeds. Yes, Larry, Marketing bullshit is what I did to make money, I'm comfortably retired from marketing bullshit. that's one reason why I know what it is.

e. When you climb the bow wave with a rockered hull, more and more of the nose sticks out of the water. That means you have a shorter waterline, which makes the speed that the froude "limit" starts getting exponential come sooner. One more reason rockered hulls don't plane. Every inch the waterline shortens is more energy required.

f. Planing happens when the hull rolls over the bow wave, or in shorthand terms, when the bow wave meets the stern wave. If you're looking at your bow wave in front of you, you are decisively NOT planing.

Most importantly, it's not me saying this. You don't have to listen to me or believe a thing I say.  Google is a click away. What you believe is meaningless. what you know is useful. You might believe in little green men, or that an invisible dead guy is running your life. Nice for you, I don't care. Look it up. read. If you find something that isn't marketing bullshit, that says I'm talking out of my ass, then I'm all ears. But SUPs aren't a bit different than any of the hulls developed over the last hundred years. You don't have to make this shit up. It's all available.

Start by reading about what Sims was up to, just trying to make a shortboard plane. But don't stop there. There's a hundred years worth of literature about this--it all says the same thing. It's just physics.

Back when the zone started there were people who wanted to punch me in the nose because I said board length was the critical determinant for the speed of a board except for special cases. Byron Yap and I got into a serious pissing match about that. The consensus was that it was all about the paddler. Here we are, talking about froude limits. Maybe people actually understand that now. Probably not. The best way to talk about any of this is with math.

And Eagle, if you're going to quote me from 2010, it would be cool to include all relevant parts of the quote, even if it doesn't help prove your point:
"without looking at rocker. Planing hulls look like surfboards, displacement hulls look like canoes."
« Last Edit: June 28, 2016, 05:46:28 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Eagle

  • Cortez Bank Status
  • *****
  • Posts: 2426
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #83 on: June 28, 2016, 07:20:36 PM »
Where is the bow wave in this pic?  It seems you are the only one who says no SUP planes or whatever.  I told you - gliding at 15 mph is perfectly ok by me.  Others now are talking about planing and whatever - leave me out of your nonsense argument.  I told you I completely understand your position.  You can leave me out of your pissing match.  SUPs do not plane.  Got that.   ;)

And the link -> anybody can go back to check for context etc - that's why it was referenced.   :)
Fast is FUN!   8)
Dominator - Touring Pintail - Bullet V2 - M14 - AS23

PonoBill

  • Cortez Bank Status
  • *****
  • Posts: 25864
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #84 on: June 28, 2016, 08:54:54 PM »
There isn't any, he's probably planing. Glad to leave you out, in fact I have been. I see no reason to contiue a conversation with you. I was responding to Robert. Included you ONLY because you quoted me.
« Last Edit: June 28, 2016, 08:56:32 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Eagle

  • Cortez Bank Status
  • *****
  • Posts: 2426
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #85 on: June 28, 2016, 09:01:50 PM »
Merci beaucoup.   ;)
Fast is FUN!   8)
Dominator - Touring Pintail - Bullet V2 - M14 - AS23

blueplanetsurf

  • Site Sponsor
  • Teahupoo Status
  • *****
  • Posts: 1896
  • Hawaii's SUP HQ
    • View Profile
    • Blue Planet Surf
Re: Scientific Flatwater Board Testing 101
« Reply #86 on: June 28, 2016, 09:45:26 PM »
We have gotten way off topic here, sorry.  Bill, you are probably right but I do enjoy arguing with you so I will keep going.
So what exactly is the scientific definition of planing?  I don't care about pounds per horsepower because we don't use motors.
I agree that semi-planing is a bullshit term but there is some kind of sliding over the water surface going on at "sub-planing" speeds.  Check out this photo, the big bow wave is coming off by the nose yet the board is still sliding over the water with dynamic lift, clearly not for much longer but to me he is still planing, right?

« Last Edit: June 28, 2016, 09:47:56 PM by blueplanetsurf »
Robert Stehlik
Blue Planet Surf Shop, Honolulu
Hawaii's SUP HQ
http://www.blueplanetsurf.com

yugi

  • Cortez Bank Status
  • *****
  • Posts: 2228
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #87 on: June 28, 2016, 10:53:19 PM »
Planing is when the bow wave joins the stern wave. Doesn’t matter where. For us on long DW boards that’ll be further back, so effectively will be out of sight for the paddler. For the skim boarder it’s happening up front - but he is planing. You can clearly see there aren’t 2 separate waves. That thing doesn’t have enough volume to float him if he wasn’t planing anyway.

It’s funny. When I was 14 or so, during a group conversation which involved planing, I asked what planing was to my sailing coach. His answer was short and simple: “Planing is when the bow wave joins the stern wave”. At the time I remember thinking that he hadn’t really answered my question, or certainly hadn’t helped me visualise what they were talking about. I eventually figured out what was meant by planing from the feeling, which is pretty distinctive. Over time my coaches answer stay with me and I learned to recognise it.

I do think it is a distinctive feeling. If it feels like planing it is. Whatever the craft. Motorboat, yacht, dinghy, windsurfer, SUP. You really feel it driving a wakeboard boat, like I was the other day, at slow speeds. It’s almost like a pivot point. And often the optimal wake is right around that pivot point. Tricky to drive if it isn’t one of those new boats optimised for that. Sinkers like short surfboards, skimboards, wakeboard and kite boards (the little ones) pretty much have only planing mode else they’re underwater.

blueplanetsurf

  • Site Sponsor
  • Teahupoo Status
  • *****
  • Posts: 1896
  • Hawaii's SUP HQ
    • View Profile
    • Blue Planet Surf
Re: Scientific Flatwater Board Testing 101
« Reply #88 on: June 28, 2016, 11:20:22 PM »
https://en.wikipedia.org/wiki/Planing_(boat)

I found this explanation on Wikipedia:

How planing works:
When it is at rest, a vessel's weight is borne entirely by the buoyant force. At low speeds every hull acts as a displacement hull, meaning that the buoyant force is mainly responsible for supporting the craft. As speed increases, hydrodynamic lift increases as well. In contrast, the buoyant force decreases as the hull lifts out of the water, decreasing the displaced volume. At some speed, lift becomes the predominant upward force on the hull and the vessel is planing.

« Last Edit: June 28, 2016, 11:25:15 PM by blueplanetsurf »
Robert Stehlik
Blue Planet Surf Shop, Honolulu
Hawaii's SUP HQ
http://www.blueplanetsurf.com

yugi

  • Cortez Bank Status
  • *****
  • Posts: 2228
    • View Profile
Re: Scientific Flatwater Board Testing 101
« Reply #89 on: June 28, 2016, 11:39:22 PM »
^ and we can feel that.

 


SimplePortal 2.3.7 © 2008-2024, SimplePortal