Here is what we were saying on Swaylocks about sanded versus polished back in 2003. Some very authortative discussions by some very learned folks. The universtiy guy with the long desertation was my favorite.
http://www.swaylocks.com/forum/gforum.cgi?post=123584;search_string=dimples;#123584
Lotsa hot air, no solution, or even close.
Anything from sanded 500, 1000, anything in between, polished, speedcoated, glossed, glossed with polish all work about the same.
Who needs a brainsurgeon on this subject?
Fastest bottom is a board ridden by a good surfer on a good wave. Anything else is slower!!!
I certainly can’t tell the difference. Perhaps no one can at the speeds and distances we operate in. (A tiny fraction of a foot per second over a 1500 mile ocean race is another story).
But I’m glad someone put the dimpled golf ball theory to rest. That was going to be nothing but trouble for the glasser and the sander.
One thing I said that I should have been more clear about is…
…I think out of that whole thinking came the dimple bottom boards, venturi hulls, etc. Trying to take the air cushion thing to it’s extreme. But I do think that in time some of those extremes will run their course, …
…not that the extremes mentioned (and others) don’t have merit, I think they do, it’s more about the ____________ that are resistant to greater departures from the norm or the time proven designs. A quote I have heard allot from surfers is: “If it’s that great, then why aren’t the top pros using it to win contests?” Sorry to bring that up, but that seems to be the measuring stick most typical short board surfers lay on their surfboards.
Ok, that said, . . .
Of course we are talking about the finer shades of grey, things that might only make a small (or more) difference at best, but all of this great feedback should help everyone to make a more informed decision about their own personal preferences. Whether to reinforce them, or to alter them. I look forward to seeing lots more input.
"Problem with using yaks or boats is that thems vehicles, the rider doesn’t shift his weight to affect surface area!
Surfers do, like trim, lean back, forwards, unweight.
That’s why no one knows! Just like in wndsurfing, no one knows!
Didja foresee that one?
Kayaks and boats definately use rider weight to affect surface area. Infact, downwind in a laser (olympic singlehanded sailboat) the real race is who can stay on each wave longer, as you are surfing the boats downwind (much faster sailing down a wave than not). Trimming the boat with your weight does more than this than a rudder ever could, and its remarkably similar to surfing, moving foward to get going down the wave , back to keep from plowing into the face of the wave ahead of you, turning is backwards, you actually lean opposit the way you want to turn, but bodyweight is certainly the most dynamic factor in steering the boat. I’m sure that kayaks are used in similar ways. It seems to me though that the bottom treatments aren’t for operating in planing mode, but are for when the hull is operating in displacement mode and drag is a bigger factor. So a bottom finish might not help you on a wave, but it might make it a very little bit easier to paddle, (or the slick bottom might just make it that much harder to carry the board).
Gotta agree a prepared bottom surface will affect paddling speeds, and possibly noticeably.
Like your examples, yes, to an extent, small planing craft like lazers, Aussie18’s, 470’s, 505’s, and plenty more can plane down windswells, minimizing the effect of water drag from the entire hull to only part of the entire unit.
But still not directly applicable to increasing boardspeed on a wave. Surfers use different kinds of boards, which get speed from different surfing methods. ONE prepared bottom is not going to work well in all conditions, hence the failure of speedskins, spray-on, dimples, and all that stuff.
Plus, boats don’t need to turn hard and carve, while a surboard spends more time turning and carving than trying to achieve ultimate board speed.
We have no problems making a wave that is makeable.
Our only problem is we can’t turn as quickly or as precisely as the top pros.
One great example of how a bottom surface preparation can affect speed on a wave face was the Schock 35 fleet and Water Mocassin.The Schock 35 was the predominant Southern California one design fleet keel boat fleet. Due to their size they were kept in the water and an antifoulant coating was allowed. Now these boats are regulated by a set of rules to keep them all the same. Part of the rules had to do with the shape of the bottom and keel. Schock Manufacturing has a set of templates that each boat must fit within. But, straight from the factory there would always be some variance in the bottom and appendage surfaces that could be fared out. We prepared several of the top boats in the fleet. We would spray a hard vinyl anti-foulant on the bottoms for $1,800.00. We’d fare the keel and rudders for $8,000.00 and if they wanted to go all out for $20,000.00 We’d fare the entire bottom and appendages to perfect design specs. On the race course, Water Mocassin (the first boat to do the whole package) said normally sailing down wind in 8-10knots the fleet would get little surges as a series of waves would pass through. But, Water Mocassin would hook up and ride right through the fleet. She won the class championships that year and for the next three years they went back and forth with Mischief another complete bottom package. Bottom prep works. But, it’s not just the surface finish, it’s also about symetry and continuity of the surfaces.
The dept. of the navy contracted with the University of California Santa Cruz in the late 60’s early 70’s to determine the effectiveness of laminar flow on roughened surfaces for our naval vessels. They did in fact encrease speed, once they had passed the level of 57 nauts, far below where any surfboards will ever go.
I think Greg Liddle, and Kirk might be able to chime in here, leaves the bottoms of his boards unfinished (looks like hot coat) and instructs the owners of his boards to sand them to make them more slipery to water.
I will always suggest that the finish coated bottom be wet sanded with #320 or #420 wet /dry sandpaper. Use water and sand in same direction as the stringer from nose to tail, tail to nose, do the fins and rails too. You will notice that the water will stick to the wetsanded bottom and feel very different from the finish/polished bottom. The result feels faster to me, more under control and more conected to the wave. You can try it on any board you are used to. Ride it glossed first, wet sand the bottom and try it again to feel the difference. The board can be freshened periodically in this way if it becomes dead and sluggish.
Greg Tate’s got it right. I talked this over 20 (30?) years ago when my little brother was on the U of Hawaii sailing team. He went on to bigger things in sailing, like Transpac, deliveries, skipper-for-hire, etc. Sailors, particularly the then-popular Hobie cat-ters, were big on surface finish back then. But the simple fact is that if you do the math, and you’re a few percent faster (what a sailboat could expect) over a 100-yard ride (how many of us ride that far at speed?), in the end it really won’t matter.
Surfboards are planing craft in action (and displacement craft otherwise). I don’t think there’s ANYTHING AT ALL USEFUL to be gained for paddling speed. And in planing mode, if we were trying to operate at full speed all the time, this discussion might be relevant. But we’re not. I just got in from a 3-hour session where most of what was available was shoulder high (if you’re lucky), peaky, backing off and generally pretty extraordinarily average. Top speed was never, I repeat never, and issue.
Bill B, I can maybe see a use for a few percent if one takes off deep at Pipe. But hey, if you didn’t make it, don’t take off so deep next time, or modify your entry a little. That tiny fraction of speed that might be there for the right wave, the right finish, the right yadda yadda, you MIGHT use once in a great while. But for the most part, a little better line, a better entry, and so on will get you there.
i like smooth small round bottoms the best
not big on pimples
and hairy ones are deffinately out
in fact im more of a breast man really
So this thread seems to have run its course…
The question was posed… Rough vs Smooth which Bottom is better?
The question as phrased, presumes a winner. Is there one?
We all know that better waves, better surfers and better boards. can override the effects of pretty much any normal “bottom finish” on speed. But the question wasn’t asking which finish would win a “speed” race. But rather ambiguously, which was “better”.
Better to me isn’t necessarily faster. Nor does it mean I would use only that “better” finish forever. Better in surfing is often just “different”. Different feelings, different looks, different styles, different effects, different performance or just simply “different” as each individual sees it. Kind of like wandering through a great museum. Different stuff, all “better” to someone somewhere.
Having sailed and yacht raced for years. I can attest that Sanded finishes on boats are faster. Mostly because bottom paint to resist organic growth, goes on pretty rough. And sanding the paint or the bottom in the water cleans the hull of all kinds of speed reducing growth.
When I was racing my yacht Hallelujah, it was competitive but not as fast as it should be. I hauled it out, took in home and reworked the whole bottom and keel. It was way out of spec. When it was done it was very fair and clean. I sprayed on the bottom paint and wet sanded it smooth. It was much, much faster! Probably due primarily to the now perfectly fair bottom and the ability of the water to flow better around it. But maybe… just maybe…also due to those fine sanding scratches. Hard to say.
But then this was a displacement hull that rarely planed. And any drag induced, by obstacles in the water flow, are huge when you have 100% water contact. Especially with a huge object that is trying to be pushed under weak, natural, forms of propulsion.
On a surfboard it is my opinion, that so much less of the board is in continuous contact with the water and that that water is coming from so many directions both horizontal and vertical that there is no real comparison to Yacht and displacement hulls and water flow.
Some might consider that small one design boats like Lasers or Finns are similar enough to surfboards but I don’t think they are that much either. Their wetted surface area is huge, and the water flow is generally much more consistent and predictable.
I don’t think there are really other vehicles that accurately resemble the way a surfboard interacts with the water, the rider and the power source. This doesn’t mean that there aren’t similarities that can be theorized and discussed to death. As we see in these “bottom finish” discussions, they just never lead to any real or verifiable conclusions. But they are none the less fun and interesting.
Does that mean bottom finishes don’t really matter? Some would say yes. And some would say no. That board I was riding in the Late Take Off photo posted earlier had a 600 grit, longitudinally, hand sanded finish. I was taking no chances in those days and was apparently way ahead of the sanded finish craze of today. Though for totally different reasons. I was seeking impeccable performance. I don’t think that has much to do with why sanded finishes are on most boards today.
Are there other issues effecting surfboard performance that can more easily have a greater effect on the way a board “feels”? Of course. Does that mean we should ignore the bottom finish? Of course not. Does it mean that we can ignore it, and not suffer some dramatic penalty in performance or customer dissatisfaction? Probably. Does that make it ok? For some yes for others not. Whatever rings their bells.
How much one cares about details and how much those details that they care about matters to themselves, others, and the activity or the business surrounding that activity, takes us back again to that thing that makes surfing so attractive to a particular kind of person. No finish lines. No absolutes. No clear winners. No clear losers. Just plenty of room and ambiguity, for everyone’s egos and self esteem needs, to find a comfortable home with little drama. When I race DownHill Mountain bikes I install a fresh set of tires for race day. I do so because it matters allot and makes a noticeable difference. And it is one more thing I can trust in and dismiss from my mind so that I can focus on other equally important things that I have less direct control over. Few surfers sand or prep their bottoms before hitting the water. But then there isn’t a finish line and clock running that will measure whether or not it made a 100th of a second difference.
So in the end…can a bottom finish really effect the way a board rides. My experience would say absolutely YES. Is that effect enough to really matter to most. I would say probably not. Is there anything left then of this discussion?
Well… we never really got into sacrificial finishes that can be applied to boards that can pretty easily be felt by the rider. Or some of the Hydrophilic coatings that absorb water and leave a slimy, super slippery finish on the boards. But then maybe it doesn’t really matter anyway. And what about those “bubbles trapped in the tiny groves of the sanded finish”. No one was able to confirm or deny their existence or where the rumor/fact came from.
And lastly who among you, have committed to trying several different finishes on exactly the same board in similar surf, without changing anything else and will report their findings here on Swaylock’s. Hundreds of members and lurkers might actually be able to come to some kind of general consensus. That would be pretty cool. But most surfers and the reasons they surf aren’t reallly about that kind of discipline and effort. Or are they?
But most surfers and the reasons they surf aren't reallly about that kind of discipline and effort. Or are they?
I sure would be if I had the time and surfboards. I do have the time…
The following from George Greenough, speaking about surfing and his flexible spoon kneeboards, wet-sanded over their length with 400-600 grit. Consider the context, in contrast to mainstream surfing of the latter 1960’s:
"… basically with flex I’ve got variable rocker. It’s hard to say how much power (snap) I’m getting out of these things, but by designing them to stay with the waterflow I’m certainly reducing the drag a lot. My board is a ‘stress-structure’; it transmits force like a torsion bar; it bends and gives way to the wave and keeps a smooth water-flow at all times…
…it seems true that in anything, what you’re seeking is a very high level of concentration… so that you’re not aware of anything else that’s going on around you. When you’re pushing it to the limit, you don’t want to be aware of that board at all. You want to be freely involved. And that’s why you want neutral handling…
Total performance is what I’m after. Not any one thing. Today everyone wants to hug the curl as close as possible. There are other aspects of surfing besides that: speed and acceleration just two of them…
What I want in a board is something that’s uncomplicated;
something you can ride straight off; something you can set up tubes with or drive through sections or do anything else you feel like doing. The board is supposed to feed you information through your feet or your hands or or your body; it has to to tell you what’s going on. If you’re operating right next to the limit, your margin of error is practically nothing, plus or minus a few hundredths of a second… if you don’t know where this limit is, you don’t want to even get anywhere near it. But if everything is working together… if the board is neutral handling this
(limit) will happen gradually…"
Excerpts from “One step beyond… The Legend of George Greenough”, an interview with Bill Cleary.
It seems like true cutting edge designs are never realized at the time.
Dale, that kind of reminds me of something I read about Simon Anderson. During one of his first experiments with the thruster, he was walking up the beach with his board while some people were laughing at that stupid third fin.
Bill, I think PlusOneShaper may have hit on the theory reference with his thoughts on “Free Surface Aeriation” in relation to reducing the drag in the water. I wonder if that had anything to do with the original “tiny bubbles” thinking.
Besides somewhat of a consenses of a 400-600 grit sanded finish, there were some very interesting points made and proposed that seem to stand out above the rest. (To me anyway.) Including that it might only make a miniscule difference at best (or maybe more). But even if that’s true, your going to have to finish sand or seal your board anyway, so why not do it one particular way that might give you an extra 1% or 2%?
So, the real question may not be if we want an entire bottom to be one style of finish, rather what texture goes where…
…race glaze for kayaks…
…teflon speed finish for boat hulls… (from the high performance thread I think)
…a hydrophillic finish…
and a few others that are too numerous to mention. All duely noted and filed away in the grey matter.
Ok so I’ve been thinking about this and while we may be getting to such a minscule level as to not be noticable, I wonder if sanding across the board may make a difference? Lengthwise sanding is basically putting very fine grooves in the bottom surface from tip to tail. Very small in our perspective, but will serve to increase the surface area with all the peaks and valleys.
What I am thinking is if sanding sideways from rail to rail, is it possible that this could be setting up a tumbling water type of scenario not unlike using a series of round logs to roll a heavy object a distance? Much less resistance is exerted from a rolling log compared to sliding an object lengthwise along a log. I guess this is all hypothetical, but I envision a tiny layer of turbulent water tumbling along the bottom of the board from tip to tail like a board rolling across thousands of tiny logs.
Am I crazy? Certainly, but if I’m bored one day I may have to give it a go.
No, you’re not crazy at all. And you may be right. I think sanding direction was mentioned before. Sanding parallel to the fin’s toe-in line and sanding in a crosshatch pattern.
Of course everyone isn’t going to run out and start doing it a certain way, but it doesn’t cost us anything to discuss it. I enjoy everyone bouncing ideas and theories off of each other, no matter how far out of the ‘practical’ zone they are.
Quote:But most surfers and the reasons they surf aren't reallly about that kind of discipline and effort. Or are they?I sure would be if I had the time and surfboards. I do have the time…
So how many boards do you think you need for this experiment? I am pretty sure you only need one. In fact, more boards will only complicate things. Time is all you really need!
If you have just one board, sand it…go ride it.
Then sand or gloss the bottom differently…and ride it.
Then polish it with car wax or some other “coating” and ride it.
Then after you have done this with a few different finishes on exactly the same board tell us what your conclusions are. If 100 guys do this we may have something. Talk is cheap!
This isn’t a rich mans experiment. In fact it actually requires someone just like you who has the time. Now the question is…do you have the commitment to the task?
Swaylock’s is awaiting the results of your testing
Quote:Quote:But most surfers and the reasons they surf aren’t reallly about that kind of discipline and effort. Or are they?
I sure would be if I had the time and surfboards. I do have the time…
If 100 guys do this we may have something. Talk is cheap!
This isn’t a rich mans experiment. In fact it actually requires someone just like you who has the time. Now the question is…do you have the commitment to the task?
Swaylock’s is awaiting the results of your testing
I’m in! I have a good all around board that is sanded 400 finish right now and that’s where I can start… All we need is the other 99 guys. Heck, all we need is 10 guys who can surf 1/2 way decent to do a good test right? Let’s do this guys! Should be fun…