Waxing a kayak make it "faster" ?

[spider]

I try to wash a kayak every time I take it for a paddle.

Every so often I will wax them (or 303 if that is what has always been used on them.)

So while waxing the hull of one the other day I'm saying to myself "oh she'll be gliding through the water in fine time now.

...Then I got to wondering... is that even true ?

You see a lot about what style boat and what type of paddle etc etc. Do racers wax up their boat just like skiers do their skies ? I know surfers use wax but I have no idea why..?

Or is waxing a fiberglass boat a moot point because it already has a glass like finish etc...

I know if I 303 a kayak and put it on the roof racks it's going to slide off in a blink...does that extra slipperiness translate to our advantage when paddling ?

Edited April 10, 2013 by spider

[Doug]

I'm sure Leon will chime in shortly on this one but I believe a rough un-waxed hull will make the boat go faster. Something to do with a porous or scratched hull encapsulating air molecules which create less friction against the water or something like that.

Let the barrage of responses begin!

[leong]

I try to wash a kayak every time I take it for a paddle.

Every so often I will wax them (or 303 if that is what has always been used on them.)

So while waxing the hull of one the other day I'm saying to myself "oh she'll be gliding through the water in fine time now.

...Then I got to wondering... is that even true ?

You see a lot about what style boat and what type of paddle etc etc. Do racers wax up their boat just like skiers do their skies ? I know surfers use wax but I have no idea why..?

Or is waxing a fiberglass boat a moot point because it already has a glass like finish etc...

I know if I 303 a kayak and put it on the roof racks it's going to slide off in a blink...does that extra slipperiness translate to our advantage when paddling ?

The short answer is that waxes that are hydrophobic (make water bead up) probably slow a boat down a little. I’m not sure, but I think 303 is slightly hydrophobic. On the other hand, waxing a boat is more for protecting it than anything else. Greg Barton says here http://www.epickayaks.com/news/news/to-wax-or-not-to-wax,

“I'm often asked, will waxing my kayak make it faster? There are two schools of thought here. The first is that waxing will make the hull surface smoother, slipperier and faster. The other is that wax causes water to bead up on the hull and the added surface tension actually makes your boat slower. My experience has been that neither is true…”

My own opinion is that the difference in speed is negligible.

-Leon

[Phil Allen]

Surfer's wax the top of their board. Gives them friction to the feet. On the boat it's probably just a sacrificial layer to interact with some of the oxidants that would otherwise attack the hull (UV, ozone....)

best

Phil

[lhunt]

Greg Barton says here http://www.epickayaks.com/news/news/to-wax-or-not-to-wax

(I fixed the link in the above)

I'm sure Leon will chime in shortly on this one but I believe a rough un-waxed hull will make the boat go faster. Something to do with a porous or scratched hull encapsulating air molecules which create less friction against the water or something like that.

Let the barrage of responses begin!

I do think the hull should be as smooth as possible, with or without the wax.

-Lisa

[Phil Allen]

(I fixed the link in the above)

I do think the hull should be as smooth as possible, with or without the wax.

-Lisa

Not that anybody is building kayaks this way at the moment, but smooth doesn't alway equal faster:

http://intellectualventureslab.com/?p=2567

small scale dimples and ribs can enhance speed by reducing viscous drag

Phil

[jason]

Not that anybody is building kayaks this way at the moment, but smooth doesn't alway equal faster:

http://intellectualventureslab.com/?p=2567

small scale dimples and ribs can enhance speed by reducing viscous drag

Phil

Sailboat racing rules:

53 SKIN FRICTION

A boat shall not eject or release a substance, such as a polymer, or

have specially textured surfaces that could improve the character of

the flow of water inside the boundary layer.

[spider]

Very interesting. The whole thing with polymers dissolving in water to reduce friction etc, there's something I never would have realized even existed.

I see Greg Barton is all about a smooth surface, not waxes and stuff, but smooth and clean. He makes a point of saying a dirty boat, with crud and stuff on it will be slower because of increased drag.

Interesting also one of the boats he was racing could not be used because it had lengthwise grooves on it .

Also interesting that what may work in dry conditions, like 303 and sliding off the roof racks, might not be the same once in the water..then I would imagine more differences between how it reacts to fresh or salt water etc.

all and all it seems all about clean and smooth with wax an option to help with the smoothness but not really helping as far as slipperiness" goes..if I understand correctly.

Edited April 12, 2013 by spider

[Pintail]

I think that the prime example of something not being smooth for speed is surely the humble golfball? (I do not claim to understand the theory, mind).

Re washing your boat off every time you paddle, Spider: no can do, personally! That would mean a daily wash in the summer months and there is no way I can do that -- a bit of a waste of water, too, I reckon. As for 303, I coat my hatch covers liberally with the stuff at least weekly, if not more often; but on a boat hull? It is expensive stuff and I would never waste it on a hull! Management of New England Small Craft (Mr. Thomas -- Joel) has long advocated against this practice, saying it only causes streaking on the hull. He prefers to wax boats with a good-quality wax polish for ultraviolet protection -- and so do I.

As for speed in the water -- Doug was getting close: it is all a matter of boundary-layer control; but, curiously, competitive glider pilots (pilots of sailplanes, if you prefer) often treat their wings to a light abrasive before competition!

[spider]

... I'll let Doug and Greg hash it out...

but sure I rinse my boat, daily (spray skirt, pfd as well)

if I paddle daily.

no problem at all, I certainly don't look at it as a waste of water, I look at it as water put to good use and not watering some lawn for example.

The exceptions are of course on camping trips or portages from one body of water to another, then best I can do is wait till after the trip.

probably got in the habit coming up to kayaking from early days of renting, the outfitters always washed(rinsed) their gear when you returned, always thought that was a good habit and your gear last longer esp from abrasive salt.

If paddling fresh water the motivation to clean gear seems even greater so we don't spread invasives..but nothing to do with boat speed and what not

[leong]

Please don’t tell anyone (especially Lisa and the Blackburn folks), but I’ve ordered some synthetic sharkskin to cover my hull and the non-power face of my wing blades. The tiny denticles on the hull are to reduce drag, but those on the blades are to increase thrust.

-Leon

PS
To all concerned: The Cape Ann Rowing Club (CARC) has a new rule for the Blackburn and Essex races:
The Surfski 20 Plus (SS20Plus) class is a new class for 2013. This class will include surfskis whose beam is greater then 20 inches. Anyone paddling a SS20Plus surfski can still participate in the HPK class if they would like, but no longer the FSK class like prior years.

Ha ha, with this new rule and my new shark skin duds, I’ll do relatively better in the races.

[JohnHuth]

I think that the prime example of something not being smooth for speed is surely the humble golfball?

Different effect. The dimples help grab the air as the ball spins, giving it lift from the Bernoulli effect.

I have no idea about smooth wax on a kayak hull - probably a small effect.

[leong]

Different effect. The dimples help grab the air as the ball spins, giving it lift from the Bernoulli effect.

Yes, but there is also a range of velocities where a dimpled golf ball experiences less drag than a smooth ball. The lift effect is more significant, though.

Edited April 12, 2013 by leong

[leong]

This article about waxing is interesting. Perhaps Barton is wrong.

From “Physics of Sailing” issue 5/24/11

Wax On, Wax Off?

This may be silly because it questions some basic ideas from fluid mechanics.

The “no-slip” condition of fluid mechanics tells us that waxing a sailboat hull is a waste of time. Could it be that this condition is wrong? Perhaps so. In recent years, there have been some experiments suggesting that hydrophobic surfaces (like wax) manage to produce less drag.

[Note, I couldn’t reproduce the picture here, but here’s a link]

The picture suggests that there might be something different than ordinary water near the hydrophobic (water repellent) surface. One possibility is that tiny bubbles of air or water vapor inhabit the nooks and crannies of the surface. This is consistent with the observation that the reduced drag appears to be smaller on atomically smooth surfaces. There are more radical theories that say water could adapt a quasi-layered structure near the surface.

Wax is not the most hydrophobic material. The reported experiments use compounds related to silane, which is methane with the carbon atom replaced by a silicon atom. In principle, a sailor should coat his boat’s hull with dimethyldichlorosilane to achieve maximum speed. This would probably be expensive.

Two of many references are: Physical Review E, Volume 80, article 060601 published in 2009, and Physics of Fluids, Volume 16, page 4635 published in 2004.

[Brian Nystrom]

Whatever the truth is - if there even is an absolute answer for all conditions - it's obvious that waxing doesn't make any significant difference. The scratches on the hull have a far greater impact, so unless you're willing to apply enough wax to fill in all those irregularities, you're wasting your time from a performance perspective. Protecting the surface from oxidation is another matter entirely and it's realistically the only valid reason for waxing a kayak. However, unless you carry and store your boats upside-down in the sun, there's little point in waxing anything other than the deck.

[Pintail]

I <do> store my boats upside-down and I <do> wax them regularly, actually. I believe that even semi-filling any gouges in the gelcoat with wax can be helpful in keeping the boats in good shape and I also use plenty of 303 on the hatch covers. Each to his or her own...

As for speed, as noted last year, competitive glider pilots use very fine sanding material on their wings prior to competition! I am sure they know a thing or two.

(Oh, yes: I see that I'm a guest! I suppose I have not yet paid my dues -- been a member of this here outfit for loooong time. I believe our founder may be in the area: anyone?)