I’ve been around snowboarding for a long time. It might be worth a second to see how the boards evolved, from rear-finned, vee-bottom tails to no-finned sidecut, flat bottoms.
Back in the day, we had vee-bottom and shallow 1/2" inch deep 4-6" long metal skegs along the rail and sometimes in the center of our boards. These provided directional stability and grip/holding power for turns. Boards didn’t have any real sidecut and they didn’t turn very well on hard snow. Pretty quickly, the boards got steel edges and sidecut, and the fins started to disappear. I clearly remember cautiously removing the side fins from my 1987 Burton Cruiser. It had steel edges and a vee bottom in the tail. It also had a center skeg. Taking the side fins off made no negative effect in performance, both in hard snow and powder (more surf like). In fact, taking the side fins off gave the board a more fluid engagement of the edge, and I was able to get more “drive” or “propulsion” out of turns. It was even more scary to take the center fin out, but once again, it actually improved things. You relied on the rails (steel edges) to dictate your turns and get drive. Stances moved from the tail up to about the center of the board’s sidecut. Snowboarding made a huge performance leap when boards evolved to pure sidecuts, flat bottoms, no fins, and a stance centered over the sidecut. This applies to both hard snow AND powder (more surf like).
So I’ve always wondered what it would be like to make a surfboard with sidecut, where you are standing centered on the sidecut, and you have no fins and hard-ish edges, and a decent flex pattern. My friend Steve O’hara from NH experimented with this back then. He literally traced the sidecut of a Burton Custom onto a blank and shaped a board like I describe. I think it had fins in the back though. I know he rode that board all over the world and loved it. Don’t know if/how it evolved.
Since we are getting technical, I think I should correct some of your misconceptions…
Really, the only sources of energy in surfing are the wave and the rider. Gravity is a given; as long as you are on earth, its effect is always present. It is what gives you your weight. When you jump in the air, and land back on the ground, you don’t say “gravity provided the propulsion”. What happened was you, through the “work” of jumping, provided the potential engery to fall back down. All of the energy was provided by you.
The same thing is happening in surfing. The wave lifts you up, and provides the potential energy (that can be converted to kinetic energy).
Through the surfboard (hull and fins) you are able to control how the waves energy is converted to potential engery, that you can turn into kinetic energy.
I don’t know how you want to define propulsion, but the conversion of the waves energy to the rider, through the hull/fins, seems to fit the definition. Sailboats convert the wind’s energy into propulsion, birds convert wind energy into propulsion, cars convert the fuel’s energy into propulsion. On a basic level, it seems that hull/fins, do the same thing.
The conversion of the wave’s energy (propulsion) doesn’t “have” to come from aft. It is just that it is the most efficient when it does. The less wetted surface area you create, the less drag you create, and the more efficient the conversion of the waves energy to surfer potential energy.
The further forward the fins, the more drag the hull creates, and the less efficient the conversion of wave energy.
Gentleman, talk is cheap. Why don’t one of you plop a couple of FCS plugs in the center of a board, or near the rail at the center and see what it feels like? Better yet use probox or 4way and play around even more.
Oh, and one thought about the pics of the sharks- sharks are always under water, boards are not. If you look at under water shots of surfboards usually only 1/3 of the rear 1/3 of the board is in the water (when turning). What came first- the egg or the chicken? Are the fins back there because of the way the board turns? Or do boards turn like that because that’s where we put the fins?
Talk might be cheap, but understanding what is actually happening under a surfboard while surfing isn’t.
Fins are back there because that is where they are most efficient. If they are to far forward you need more hull in the water (wetted surface area) for them to operate, and you create more drag (and too much lift from the hull aft of the fins).
As with all design elements there is a balance of factors. You could definately design a board with fins way forward, but you would have to alter many other design elements, and even your approach to the wave, to make it work for you.
This thread is a perfect example of the reason I seldom get involved in such discussions.
The reason being that if I do write something. It often either gets quoted as being written by someone else orsomeone quotes me with text that isn’t mine.
I dropped a little natical and fluid theroy above to try to put things in perspective.
Some of the notions presented above are so far from reality they aren’t worth contesting.
With the chance I may offend I suggest a little reading be done.
Some of the notions and rebuttles above aren’t worth contesting.
If you choose to go scalar have at it.
There are a few good laughs above but gentlemen, go forth sans Halcyon (-;
Well, it is pretty easy to get confused when trying to understand this stuff. It is very complicated. You really have to be able to think if 4D, most of us are only trained to think in 2D.
It is not easy to put this stuff into words, and not be misunderstood, so I understand why a lot of guys in “the know” don’t have the patience to explain it.
I'm still keen to have my plugs right under my heels and toes , as per the 'speaking of bob mctavish' thread I posted [which also got minimal replies and comment ].
llilibel says it best IMO. that’s why i can’t easily agree with the statement that ‘fins provide propulsion’. like channels & concaves, fins are there to redirect water flow, and ultimately it’s the rider who controls where the board goes on a wave-- the source of propulsion-- by shifting his weight.
going back to the shark porn i pasted previously, i can’t help but see how darts are built the same way.
remove the tail-flights off a dart and try launching it the same way as normal, and its flight path draws a tighter curve, on a shorter arc. but once you move it closer to the center of its mass, interesting things happen (try it).
that’s why i can’t shake off the idea that alaia-like, more fluid maneuvers & different lines on a wave are highly doable when you move the fin cluster (and your stance) close to your board’s center of mass, like about a step back from COM. in a fish/shark/whale/dolphin, this would be at the dorsal fin location.
The logical conclusion of your argument is that sails on boats don’t provide propulsion, and engines in cars don’t provide propulsion. As these are the things that convert energy, wind and combustion, respecively, just as the fins (and hull) convert the wave energy to the rider. And I am sure you would agree that this is an absurd conclusion.
Propulsion is “the act of moving a thing forward”. Objects that have propulsion systems (sails on boats; engines on cars; fins/hulls on surfboards) convert energy (wind; combustion; wave, respectively) to propel an object forward.
not to be obstinate, but as you recall this was being mentioned by other thread contributors in terms of absolutes. a matter of semantics obviously, but your clarification distinguishing what’s basic energy “as-a-source-of-propulsion” and what are “propulsion systems” is very much appreciated.
however going back to the original premise, what’s being discussed is whether moving the fin cluster away from the tail and close to mid-board will fail, or fly.
to address this, it would be good to also distinguish the manner of surfing that each of us is accustomed to— which is “fixed” if one is an old dog too old to improvise, from board design— which is flexible if one keeps an open mind " )
seeing that pair of newfangled boards with the fins behind the nose tells me somebody has been mulling this for a long time, and went for it.
Haha, I have no idea. Would be an interesting stand up ride though. And I actually might have seen something like this at Sacred Craft 2 years ago in Del Mar, can’t remember exactly but I’m pretty sure they were stand up craft.
would this forward fin placement be kinder to older joints ?
this is in consideration of the surf injuries mentioned in other threads detailing joints temporarily / permanently damaged due to turning maneuvers. backfoot surfers, anyone?
btw huie, seems like you’d been toying with this fins-forward simmons, how does it ride ?
Its great to be communicating with you and know you quest for answers with a reason, rather than answers just because. Some clever guys on your threads.
The fins further up the board is certainly an interesting concept. After trying it and seeing how solid and fast the board was in a barrel, there is definitely something there to pursue. rear fin = normal position, thruster side fins = normal position, plus another two side fins towards the nose (about the same distance as thruster side fins are away from the rear fin) so 5 fins. My memory was that configuration doesn’t work, the board wants to flip over all time, got grab the rail and fight it, but its acceleration in the tube is unbelievable, each time I came out of impossible tubes I couldn’t believe it. Mind you I am a small wave surfer, and these experiences were on small shoulder high waves.
I’ve made two boards with those fin options, one was a belly board, got stolen, or should I say I lent it and they moved. The other a standup and I have that with me now. I could try it again and maybe get friends to try it and get footage and reassess my opinion for you. Give a ride report in a few weeks (I live 200 ks from the coast at the moment)
Hey Surfiber heres a thought, wings out the side of the board about a foot long.
Two wings, step off the board stand on the wings.
Good fun!
PS Thanks for the response on my other thread, figured a response here is more relevant when talking about fins further up the board.
