Op-Ed: How Many SUP Board Classes Should There Be?

Lisa Schell Explore Leave a Comment

How Many SUP Board Classes Should There be

Editor’s Note: More thoughts on board lengths and classes from marketer and co-founder of Ke Nalu paddles Bill Babcock

How about NONE. None is a nice round number.

Why do we even have board classes? Before you start explaining hydrodynamics to me, or what airlines will carry, or how high the ceiling is in most surf shops you should understand that I’ve heard all that and I know it’s 98 percent bullshit. Suspend your disbelief for a few hundred words and I’ll explain.

We have board classes because it’s easier to copy what other people are doing than it is to figure out what works best. Well that, and some short-sighted self-interest. The lengths chosen were stunningly arbitrary. You didn’t really think there was a logical reason to have 12’6 and 14, did you?

I’m going to explain how eliminating board classes would double the available market for SUP racing with a lightweight technical explanation since graphs and formulas right now would lose at least half the audience—which is exactly what choosing 14 feet did, so I don’t want to repeat that mistake.

Board classes create most of the problems race directors deal with, solve almost no problems in return, and cut the available pool of racers in half.  You’d think manufacturers would really hate that last outcome, because it also cuts the market for race boards in half. Unfortunately, people rarely miss what they haven’t had. Manufacturers don’t seem to really know that happened, they just know that for all the apparent interest in the latest and greatest design, the market for race boards is tiny. I’d wager that Wavestorm sells more soft-top SUPs in a day than all the race board manufacturers in the world sell in a year.

With rare exception, SUP racing events around the country are shrinking.

While some decline is natural, the decline in interest in SUP racing looks precipitous. I believe I can trace that back to some nutty notions around 2006-7 that have been causing grief ever since. So first I’ll tell a little story, then we’ll talk a little about the ramifications of these arbitrary sizes.

In the early days (oh, shit, one of those stories), more or less at the beginning of SUP racing there were no board classes. There were all kinds of odd sized boards to fit all kinds of odd sized people. Everyone raced what they had. Then came the Naish Racing Series, and the rules said no boards longer than 14’. I’m not really privy to the thinking behind that, but I suspect they didn’t want to compete with Starboard’s K15, which would comprehensively kick the butt of any Naish 14—even with me paddling the K15. The reason K15s were fast wasn’t just that it was 15 feet—the reason was that it was a light, narrow dugout with a nice hull. Notice all the fast dugout shapes today—it took ten years for people to pick up on the advantages. Whatever the reason, Naish declared 14’ to be the race board. I’m certain they didn’t expect that arbitrary choice to harden to concrete, it was just one race series, no one had to copy that, but copy they did, and the concrete hardened.

Meanwhile, at the first Battle of the Paddle, Gerry Lopez and Sparky Longley were trying to have a race that included turns and passes through the surf—something reminiscent of lifeguard races. They decided that to minimize carnage the elite level paddlers should use 12’6” boards. Other folks claim the decision was because airlines wouldn’t ship longer boards. Not always true, as the S.I.C. F16 I brought to that first race proved, but probably no one checked. So, they built a box with an inside length of 12’6” and your board had to fit. I witnessed one Elite competitor sawing off the tail of his board so it would fit.

Gerry and Sparky decided open class could race anything they wanted since they did less in the surf (yea!), but they copied the Naish notion of 14 as the standard race board and anything longer was “unlimited” class (boo!). More concrete. 12’6, 14, and unlimited. And that is really how it happened. It was just that arbitrary. Two influential races coming up with rules for their own use, and somehow, we all got stuck with them. Apparently forever.

They couldn’t have picked two worse numbers.

To start with, there isn’t a lot of difference between them. A 12’6” is 90 percent of the length of a 14’—the optimal weight range for the two board lengths deeply overlaps, so the two boards together are only an optimal board for a narrow group of people, especially after market forces have their way with design.  Every production board manufacturer wants their boards to be competitive. With a specified length, the board needs to be designed for the optimal weight paddler. For a 14’ board that used to be 170 to 190 pounds, for a 12’6” it was 150-180.

A simplified technical expiation is necessary here. A board moving through the water is subject to two main kinds of drag—let’s call them skin drag and wave drag. Skin drag is roughly linear, the longer and wider your board is, the more skin drag you have to overcome.

Wave drag starts low but climbs exponentially with speed. Think of it as trying to climb the bow wave the hull makes. The speed of that wave is a function of the distance between the bow and stern waves which is the waterline length. The waves relationship to waterline length gets expressed as the “Froude limit” you might have heard of. Not really a limit, but the curve gets pretty steep. The only real benefit of a longer board is that wave drag exceeds skin drag at a higher speed. That’s it—that’s all.

A very fit paddler that weighs substantially less than optimal won’t push the board into wave friction territory. The added length only increases skin friction with no benefit. They could go just as fast, and certain go faster for longer periods, on a shorter board that suited their available muscle mass.

The heavier paddler is always dealing with more skin friction because their board sinks deeper. But on a board designed for 190 pounds they need to move forward out of the optimal paddling area to trim. Their added muscle mass means they may be able to overcome the added skin friction and push the board into the wave-friction dominant zone, but the wave friction rises exponentially with speed. The board that is efficient at 190 pounds is draggy and slow for an equally fit 205-pound paddler.

In the simplest terms, a 14 will work for you if you have enough power to overcome the skin friction and reach a speed at or beyond the point that a line graphing wave friction crosses the skin friction line and becomes dominant. If you can’t get there, then the extra length isn’t doing you any good and you’re just wasting energy on skin friction. That’s why a 30-foot board isn’t fast with one person paddling it. Even Dave Kalama’s cousin Junya, who is one hell of a paddler and has guns the size of my legs, can’t really make a 22-foot board reach and hold efficient speed. That’s why the one he had SIC make for him is hanging on the ceiling at a coffee shop in Maui.

If you have more power than a 14’ board can use, you start pushing the board up that exponential drag curve.  It doesn’t take long to get to a point where you just can’t go faster. There are ways around the limits, and those ways make the problem worse, because they eliminate more of the potential paddlers from competition.

Where the sweet spots are.

The current sweet spot for a 14’ board is a very fit and capable paddler who is between 150 and 190 pounds, and for current leading-edge designs, 190 is very much an upper limit. The trend to narrower boards reduces skin friction and also decreases the amplitude of the bow wave. That means a smaller paddler with proportionally less muscle energy may be able to push the board to efficient speed, and the 190 pound paddlers can push further up the wave drag curve. Anyone over 190 need not apply.

It shouldn’t come as a big surprise that very fit women are suddenly very interested in 14’ boards. The trend to make them thinner pushes the lower optimal muscle mass lower, and so many women can now take advantage of longer boards,

I hear race organizers referring to extremely fit 215 pound guys as “Clydesdales”, and then in almost the same breath, complain about lack of participation and shrinking event size. The average weight of American men is 195 pounds. Half the available market are “Clydesdales”. Half. Make them race on a board that isn’t going to work for them and see how many will show up. Oh, wait, we’ve already done that.

To make matters worse, the primary path to higher speed with such a limited set of options is to make boards ever narrower. That pushes the optimal range ever lower. You might think “hey, I weigh 180, this is great news.” But one requirement of racing is other people to race with. Another is races that are successful enough to encourage organizers. The trend doesn’t favor either requirement.

Incidentally, the fit and trained 215-pound racer on an optimal board will STILL generally not beat a fit and trained 180-pound racer on an optimal board. But at least they’ll be in the same race. In most paddling sports with no limits on hull length, heavier paddlers are already disadvantaged. For the technically inclined I’ll include a link to some mathematical analysis that explains why in detail, but simply put, even with similar levels of fitness and skill, the heavier paddler is carrying proportionally more unused weight, and in water, weight is drag, and it’s not a linear function.

Organizers also complain about the small number or women participants despite a set of random and restrictive rules for women that chased far too many out of the sport. Some woman cheated with guys who entered the race expressly to let her draft and others to block for her. What tortured logic suggests using that as an excuse to set rules? We don’t need rules to disqualify cheaters, in fact it’s much easier to do it without rules, because the first thing cheaters do is haul out the rulebook to show how the rules let them get away with doing something they know is cheating. We all learned how to manage that when we were eight: “You’re a cheater, you’re out.”

The most logical-sounding argument for board length classes is “we’re already here, let’s perfect what we have”. That’s been the fundament argument against physics, logic, and marketing for the last eight years. It didn’t make sense eight years ago, and it doesn’t make sense now. And now is a fine time to ditch these destructive and arbitrary “rules”. Because they really aren’t rules. There is no organizing body that has sufficient clout to dictate any rules to event organizers. The organizing bodies that exist are just talking to themselves, trying to perpetuate unworkable ideas while providing no benefits to race organizers. So why listen?

Event organizers can choose the rules they want. They should.

Bill Babcock


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