Varying dimensions and volume

I recently “downsized” from a 7’6" “gunnish” hybrid with a relatively tapered outline, to a 6’10" hybrid “funboard” shape simply because I liked the outline of the board, the thickness (volume proportion), foil and bottom design. I found that even though the board was a full eight inches shorter, it paddled better and was easier to catch waves with. Questions of volume pretty quickly emerged in my mind. (I have no way of knowing, at this time, the actual volume of each board, but I don’t think it’s possible that the 7’6" had less volume than the 6’10".) My first assumption is that relatively balanced, equal volumes in different types of boards, built for different types of conditions would standardize the primary characteristic in a board that I’m interested in, and that seems intrinsic to surfing, i.e. the ability or ease with which one can initially catch a wave and start the ride. Once the wave is caught, different boards do different things depending upon the conditions, riders, etc. for which they were built. My second assumption is that volume is perhaps the most important feature of a surfboard when it comes to catching the wave, and that regardless of shape or design function, this ability to catch waves by means of volume designed-in can be standardized to fit different sized boards. How the volume is proportioned defines how a board performs. I’d be interested to hear anyone’s comments.

I agree, volume is a good thing in takeoffs. Watch another surfer paddle into a wave. The tails of all but the big volume longboards get buried in the wave, then trim out of the wave if the surfer catches the wave. You can fix a lot of that by increasing the floatation of the tail. If the tail floats, you trim out much earlier, and catch waves you would have missed with other tails. If you widen the tail to gain volume, your board will plane earlier in takeoffs, and at lower speeds. However, a wide tail will hinder your ability to cut into those big fast tubes. On steep drops, your board won’t turn well. Your “gunish” shape would have a narrow tail for those power drop-turns. Most commercial boards have potato chip thin tails, with little floatation. I heard a reason, to allow water to flow over the tail’s lip when accelerating and turning at drop-in. I believe that a floating tail won’t carry as much water at takeoff, and won’t need this “flow factor”. I’m no pro, but I’ve surfed a long time. I shape my tails thicker than the big guys. I think it helps me catch waves. If pro shapers had to tell the truth, they would probably admit that they shape tails thin because thin tails look sexy. -Noodle

-Noodle…how about rails? do you follow the industries low,chipped,squared rail? Or do you like fuller rounder rails?I’m talking short boards here,but any input would be accepted.Herb.

Good question. I haven’t shaped anything under 8’, but 8’to 8’6" is my concentration. I don’t like how the old longboard soft lower tail rails slow down shorter boards, and make them squirrely. They held old longboard tails in the wave, and aided in turning. Today, we can do the same thing with “V” and thruster fins, without the down sides. So the bottoms of my tail rails break away clean. Starting unwashed, my first tail rail was just an arc from the bottom edge over the tail deck. It actually worked well on the longboard. From there, I adopted a square-ish tail rail cross section with the deck crowning from the upper “edge”. This works well on the shorter boards. When you pop up on a shorter board, there’s a lot of water hanging on you and the top of the rails. I like fast running breaks, so all this water is over the board while I’m trying to drop and turn. The more buoyant tail helps trim the board early, but the square tail rails help float the tail in the drop turn. The thicker square tail rail doesn’t dig into the wave as bad, and allows the takeoff water to run off the board quicker. How do you shape your tail rails? -Noodle

As I said above, my first shape was a longboard. I put on chine nose rails, but extended them through entry… really too far. This forced my lower mid-board rail to be old style. The lower cross section was elyptical, with the foil about .85" off the bottom. The deck crown brought the rail to a blunt edge, cerca 1967. It works pretty well, but nobody wants to fall on the rail. On the following shorter boards, my lower mid-board rail cross sections have all been .9" circular arcs. They are very stable. They dig just right on turns and they trim super well on walls. They make that sucking sound… you know. I have gone hi-tech on the deck crown-upper rail cross section. I exponentially compress eliptical sections on a computer, and print them from a cad program. I spray-glue the print to 1/4" plywood, and saw out the templates. I’m compressing the deck elipse between 1.8 and 2.0 exponent. On a 3" thick board, with the .9" foil, this deck yields roughly a 1.8" semi-cylinder. It looks like a 60/40 rail because the deck is crowned just right. I’ve been questioning my circular lower rails because of entry transition. I hope this makes sense. My boards have about 3" of offset, so the entries are just a little narrower than the offset line. Water entering at the entry rail probably has to suck down pretty fast, or else push away. I’m thinking that an eliptical lower rail might have less resistance. It could transition entry rail water smoothly under the middle. Have I been doing it wrong? -Noodle

Thanks for the info Noodle. This helps a lot especially since I am designing a summer/small wave board. The only other boards I’ve seen commercially marketed that have thicker tails are Rusty surfboards.

I’ve seen some of Hamish Grahms’ boards and the tails looked a bit thicker than the standard.

I’ve seen some of Hamish Grahms’ boards and the tails looked a bit thicker > than the standard. Interesting topic here. I was wondering if it is so much a volume issue or a surface issue. Wider dimensions provide a larger surface area. Which displaces more water causing better floation and facilitates wave catching. I would also have to ride along with Herb on the role of rail shape. I am not sure about the thickness of a tail making a huge difference. I may be wrong but I think the shape of the rails and width would play a much larger role in catching waves. Also some good shoulder and back muscles help.

Interesting topic here. I was wondering if it is so much a volume issue or > a surface issue. Wider dimensions provide a larger surface area. Which > displaces more water causing better floation and facilitates wave > catching. I would also have to ride along with Herb on the role of rail > shape. I am not sure about the thickness of a tail making a huge > difference. I may be wrong but I think the shape of the rails and width > would play a much larger role in catching waves. Also some good shoulder > and back muscles help. No doubt skill is an issue but…all things being equal, etc. Re your thought my next question is, would a board with wider dimensions and a larger surface area then have the same amount of volume as a board that was narrower, but thicker? This really gets to the heart of my question of flotation i.e. would boards of varying dimensions, but the SAME volume float you the same, and would they then CATCH waves the same way (given the same rider)? My assumption is yes. I also assume that different designs yield different performance, but equal volumes (within reason and regardless of dimensions) yield equal paddling characteristics. So I am saying that volume not necessarily dimension (within reason, say one to one and a half feet) gives flotation and ease of paddling. Therefore one could design a 7’6" gun and a 6’ fish with different dimensions but roughly equal volumes that would paddle roughly the same, but surf entirely different. My brain could be completely pasted with guano here but I’d be interested in everyone’s thoughts. My next burning question is, is there a relatively easy way to measure volume in different boards with different dimensions? I could then put the assumption to the test. Or maybe someone already knows.

a big factor btwn a 6 foot and a 7-6 in paddling or catching waves is not so much volume ,but planing length,rocker,volume flow.Herb.

check out the clark foam catalog for more info.I like to put boards in my swimming pool and paddle it around.Herb.

I have to back up herb on this one. Of the 7’4" Lopez and the 6’6" Albers Egg (both pictured in the showcase) I’d swear the egg paddles better…I think that equal volume doesn’t necessarily mean equal paddle characteristics. Rocker is definately a huge factor. S

I have to back up herb on this one.>>> Of the 7’4" Lopez and the 6’6" Albers Egg (both pictured in the > showcase) I’d swear the egg paddles better…I think that equal volume > doesn’t necessarily mean equal paddle characteristics. Rocker is > definately a huge factor.>>> S Fair enough, but a couple of questions. Herb, what is “volume flow?” Sway, how specifically does rocker effect paddle characteristic? Can I assume that you mean flatter rocker paddles better? And again what about flotation? Does your 7’4" float you the same as your 6’6" regardless of paddle characteristics?

Fair enough, but a couple of questions. Herb, what is “volume > flow?” Sway, how specifically does rocker effect paddle > characteristic? Can I assume that you mean flatter rocker paddles better? > And again what about flotation? Does your 7’4" float you the same as > your 6’6" regardless of paddle characteristics? …volume flow=how the volume(thickness and width of the foam)blends with the rocker…S,BY THE WAY… NICE EGG!!!Herb.

My 6’10" everyday board has a mid-seventies plan shape w/ a 141/2" tail that ends in a 8" diamond(thin). All that area in the tail makes it so easy to drop into waves( along w/ flat rocker,7’5" A w/ Hawaiian rocker). Also it’s a M. Champbell 5-Fin Bonzer(non-tracking). The fastest board design ever.

Fair enough, but a couple of questions. Herb, what is “volume > flow?” Sway, how specifically does rocker effect paddle > characteristic? Can I assume that you mean flatter rocker paddles better? EXACTLY. You simply plane over the surface of the water much smoother. A flipped nose or a board with lots of rocker can shovel the water like a bulldozer.>>> And again what about flotation? Does your 7’4" float you the same as > your 6’6" regardless of paddle characteristics? Yeah…I’d have to say they float the same, but the egg is so much wider it feels like I’m laying on a table. The 7’4" is real narrow and tippy so while it may float me above the water the same amount, paddling can be a little more awkward.