Board length and paddling speed

Hypothetical question - imagine you have 2 boards - a 6’ and a 6’6" - identical in every way except length - as close as reasonably possible - same volume, rocker curve, bottom surface area etc (of course  thickness will vary to have the same volume, maybe even width). Do you think there would be a noticable difference in paddling speed ?

If the rocker and thickness were the same.  The volume would not be  Just based on the length the volume would be less, therefore less float and less glide.

I think rocker and length help with padding. Not sure about volume, I’ve had several smaller boards that paddled really well, as good as boards that were bigger. The profile will probably have an impact too. I think the smooth stretched out rocker longboards have helps them move faster when paddling. Similar to low rockered short boards.

I’ve been taking notice of how with short boards that have a staged rocker you can be slightly back paddling a board out but then you move up a little when you want to catch the wave. I think it takes advantage of the flatter rocker in the middle of the board. Watch the pros closely and I think you’ll see this.

Marine Architects learned along time ago that a longer hull with the with an equi displacment of a shorter wider hull will have more gulide . Now for boards it’s mostly about keeping the very inefficient hydro-dymaic shape of us humans, out of the water as much as possible. So yes if the 6’6" give a touch more float you will paddle faster in theory. But we all Know that some shorter boards with better displacement and distribution of foam will be faster and better at paddling.  

Artz knows. Basic naval architecture axiom  

Whether noticable or not in you board , jury is out. 

All the best

Yes " better" being the key word.  But "identical"rocker and volume are what was first spoken of.  L

Sounds like a great expirement to actually build 2 boards with.

All the theory and hypothesizing in the world means nothing until you build it and ride it.

Well  going to extremes, 

I have a knifed out 9’3" pin tail old school railed longboard, 22 wide barely 2.75 inches thick, 20 Lbs.

I’ve ridden a friend’s 7’2" 22.5 wide 3 1/8th thick and wider thorough nose and tail.  With the longboard flat, me sitting on it, the water level is almost over my thighs, and the thick fishy 7’2" sitting on it flat my thighs were  barely just under water.

 

I estimate the 9’3" paddling speed to be double that  of the 7’2" and the total volumes/ displacements are within 10% of each other.

 

 

Yes. The 6-6 will have more volume…paddle better…

Pat…you have alot of work to do. On one hand it is a simple question…but on the other hand it is complex.

You just can’t build a 6 footer and a 6-6 that are identical…That’s why we have blank catalogs…got to scale up for bigger board.

The masters are here to help us…I’m a big fan of US Blanks…

went back and re read Pat’s stuff.

Pat,a 6-0 and a 6-6 with the same “volume” are out of the ball park different…

when you start building your own and stop reading the mags …wow!

time for Patrick to build 2 surfboards.

I will say that no matter how long; if the bottom contours aren’t right it’ll paddle like a packing crate.  L

OK so it is my understanding that acording to hydrodynamic principle that the simple answer in the hypothetical relm would be Yes! The longer rail in the water, and the stretched out plan shape (which would reduce the boards form drag) will make for a faster moving board durring paddling… 

If you take in to consideration that when you are paddleing a board you are not traveling at planeing speed and a boards plan shape and rocker are displacing water, effectivly reducing the hull,  and power source into a displacement craft. And it is known that the high aspect ratio hull can obtain higher speeds with more stability than a low aspect ratio hull.

But I really dont think that these boards are compareable if the two are built for the same surfer then they are different boards. So they will function differently, if they are built for two different riders then they are not compareable because you have two different power sources.

And in true scientific form to state a hypothesis you weould need to have an expierement outlined with a controll subject, so a board with same volume, width, but being 6’3"in length, would be needed, and then compare the other two solely to it not to each other…

 

 

OK… my opinion, 6’ 6" with same overall dimensions, rocker and volume as a 6’ 0" board, the 6" 6" will paddle better. Depending on the surfer, the 6’ 0" should surf better in normal waves, the 6’ 6" would be better in bigger waves.

If you are just adding length, you’re just stretching out the rocker and outline. That would help make the turns a little more drawn out and I’m thinking the stretched out rocker reduces the curve up front and should reduce resistance in paddling.

If you take your 6’ 0" board and add 6" continuing the original rocker, you’ll be adding rocker, probably a lot in the nose. You’ll be reducing thickness to maintain volume, the board may sit in the water differently and that can also affect paddling.

I have a few 6’0’s and a 7’0 kneeboard with the same basic rocker and rails and more or less the same volume because I designed them both for myself. Nose and tail pulled in a bit more on the 7’0, and the lead-in rocker is extended, as you’d expect (what Sharkcountry said).

I use the 7’0 when it gets big because I can paddle out of trouble quicker and it’s nice to be up and riding a bit earlier. If I was going to be in a paddle race, then the 7’0 would be the call.

The trick is to make a 5’10 that paddles like a 7’0 without puffing the volume too much.

Again;   Go back and read what was stated  in the initial post…  You are comparing apples to oranges.

I’m gonna wander off a bit from the initial question.  I make boards that are too big and too fat according to most people, but they work good for me.  The reason I make them that way is for one reason: paddling ease and speed.  At my age (yes I’m an old guy!) I like to be able to get into waves early, especially in a crowd, and I like to be able to get back out quickly after a wave.  So my boards are in the 7-8 foot and plus range, widths 21" - 23", and thickness in the 3 1/2" range.  I love the way they paddle, love the way they catch waves.  I like longboards too, but when I want to ride something other than a longboard, which is most of the time, these boards are my go-to.

Interesting reading, someone mentioned the bottom contours had a large effect, what bottom contour paddles fastest?

McDing, you got anything for us on this??? anyone else?

I personally do not have the expierencial knowledge to offer anymore than hypothetical presumptions reguarding bottom contures and paddling. I too would like to hear peoples thoughts on this aspect of design…

 

To my thinking bottom contours, at least subtle ones, don’t really come into play until the board reaches faster than paddling speed.  I suppose a flat bottom is the most efficient at paddling speed, curious what others have to say.

Sweet, thanks for that Huck.
Pretty much what I presumed.
Then I got to thinking, maybe a channel system may even increase the efficiency from there. But likely not much would be noticed until you have reached planing speed…??