How do skis react to cold water? or do they?

[scoke]

We know our bodies react to cold water so how do skis react to cold water?

 Some have consistently felt a change in their performance based on the ski, as well as physically but we are holding that a constant, in the colder water.

After some tweaking, thinking and talking to a few skiers:

http://img140.imageshack.us/img140/8885/pvt2.jpg.

 

 

[jimbrake]

that's what she said

[WadeWilliams]

resize the pic

 

skis and bodies are affected by cold water. how doesn't really matter IMO, bc,

 

as the water gets colder it is more viscous

 

colder water = thicker water = more viscous

=

thicker water = harder to slide your ski thorugh = feels "faster" because your ski rides higher in the water.

 

hotter watter = less viscous = "thinner" water = ski rides lower in the water = feels "slower"

 

Let's Visualize water molecules (disregard weight):.

 

Low viscosity = hotter water = marbles

High viscosity = colder water = basketballs

 

Think about how your ski would react in those two mediums...

tips on Cold Water Ski Setup

 

 

also would add that the chart you posted is likely true across many brands, because it is the water that changes more than your ski or your body.

 

 

________________________

wetJacket

[Tuney]

I ski in cold water - in fact it doesn't really get much warmer than high 70's for the hot parts of the year. My take on it is I am affected by the cold far more than the ski is.. mentally and physically. But my idea of cold is water in the 50's and air at a similar temp. I'm not as loose and I really don't want to fall - so my skiing isn't as good. So really I can't really blame the ski's performance or be a reliable judge of how it is affected.

[Gloersen]

Personally I note a HUGE difference here in Jax when the water gets < 66⁰F.

 

 

This is noticed mostly with regard to unpredictable & unexpected blow-outs. Additionally it does seem more difficult to create width & space. I don’t attribute this to the ski being “faster†in cold water. Faster imo equates to getting wider & earlier, somewhat counter-intuitively, a great pass (wide & early) often feels “slow†but if theoretically covering a greater distance it must be “fasterâ€. In any event, great passes are harder to come by consistently for when temp <66⁰F.

 

 

I suspect most of this is attributable to the increasing surface tension of water as the temp declines. As many have stated, the ski probably rides higher on the surface and this probably has a greater influence (viscosity influence as well) towards the tail of the ski creating a more level attitude (pitch), thereby creating more relative tip pressure, thus harder to get wider. Many advocate moving the fin forward ~.005†to accommodate; it makes sense. Based on blow-outs, I’m also inclined to drop the whole fin down (L:D unchanged) as well.

 

 

The greater viscosity of water with lower temps intuitively implies more friction (viscosity is essentially fluid friction) and thus, relative to warmer water, the ski’s response will be slower. It may seem like we are skiing “faster†but only because it is harder to create width & space; that is those less than desirable passes when one barely gets around each ball and felt as though they were rocketing, holding on with whatever can be mustered to complete a “fast†pass. Before ZO we would end the pass asking the driver how much + rpm adjust was added, the response being the time was a 17.12 or something disappointingly slower than expected…. Imagine skiing in molten lava, tomato soup,.....

 

 

IMHO cold water skis slower, we just ski crappier and feel like it is faster (just like a crappy warm water pass). It also hurts a lot more after the nasty blow-outs!

 

 

Who knows what happens with the ski’s flex; can’t imagine it getting anything other than less. How does carbon/resin flex vary with 30⁰ variations in temp?

 

 

In Florida winter sucks; unequivocally.

 

[WadeWilliams]

PFG's on it, the colder water does ski "slower" though most skiers call it "fastr"

 

faster = a feeling you get when you ski more at the buoys

 

slower = a feeling you get when you ski wider, earlier

 

since colder water = more friction = physically slower = most skiers ski more at the buoys = feels faster

 

 

______________________

water ski social network

[bmiller3536]

Yes, your ski rides higher in the water when it is colder. But I am also wearing a drysuit with some other form of clothing underneath. Does that extra weight counteract the colderwater and make your ski ride at the same depth with just shorts and vest?

Wouldn't the same principal be applied to the boat as well? So in colder water your boat would hypothetically turn less RPMs because it rides higher in the water? But I ski with PP and I use the same skier weight, crew weight etc as I used all summer.

 

[Old MS Accout]

More important, how does dual loc react to changing temps? I am sure that 3M has some studies on binding release vs temps 

[rq0013]

All I know is that i ski better and feel better when the water is around 80. We had water near 85 then had a cold rain come in dropping the temp of the lake by 15 degress. I skied aweful and as soon as it warmed back up I skied much better. I think more of it was my fin setup was for warmer water compared to colder. I used the cold water setup that wade posted and it really helped this fall.

[skibug]

The chart definitely reflects my thoughts on optimum water temp for skiing.  Seems as though my ski feels best when the water is between 75 - 85 degrees.

[Horton]

Right after the rain is the best!

[Dusty]

I'm willing to bet the most significant factor is the skier- wearing more clothing, being tighter, less flexible.  Water gets denser until about 39 degrees then gets less dense until freezing (reason ice floats, which is useful in cocktails for example).  I'd suspect  denser water would float the ski higher?  Less surface immersed= less friction= faster?  Are there any pilots or hydroplane drivers out there who can advise?

[Craig]

I posted this on TWSF about two months ago with respect to cold water skiing.  I am a 4th year PhD student and work on thermo/fluid systems in addition to skiing.  The result of this combination is that I spend a lot of time analyzing skiing.  My area of expertise helps understand some aspects of the sport to a bit more depth than most, and this issue falls into that category, I think.

Here are my thoughts verbatim from TWSF on the impact of cold water on skiing:

Everyone seems to think that density changes drastically with temperature, it does not. I have attached a plot showing how both density and surface tension change with temperature.

If you look at the maximum change (between 40F to 100F) the density of water changes 0.70%. The surface tension changes 3.3% over that same range.

However, if you look at the viscosity of water, it changes 56% over that temperature range (see attached picture on next post).

Viscosity is a fluids tendency to resist flow, as it increases the fluid will resist moving out of the way more. This could account for a ski riding a bit higher in the water and additionally it will increase skin drag (i.e. more effort to obtain the same result).

Based on the above information, I would theorize that cold water feels faster but physically skis slower.

I would add to this that there is no doubt a human factor here that is difficult to quantify (changes in flexibility due to clothing, desire, changes in strength and skill over the season, etc.).  However, the sheer magnitude of the change in viscosity would lead me to believe that water properties play some significant role in performance. This lines up with scoke's plot, so if all other things constant, a ski is going to perform differently at different water temperatures.

The most interesting part about scoke's plot is that there is a perceived optimum at all, as opposed to being near 100% for any temperature above some value.  This leads me to wonder if, as a result of a high level of sensitivity to water temperature, we have to train ourselves to perform at a specific temperature.  Meaning someone like scoke, who trains in very warm water, has adapted his style and equipment to ski his best at certain temperatures.  Whereas, I am from much further north so my optimum may be close to scoke's but maybe shifted a few degrees cooler because of how I have had to adapt my style for generally cooler conditions.  This last bit is just a theory, I have no evidence to support this claim.  I would like to know what the average temperature is for scoke's ski season is, and how far off from his perceived optimum it is.

Here are some plots that show the water properties as a function of temperature.http://lh3.ggpht.com/_ZEz8NDGLxu8/TQD8P4qXV0I/AAAAAAAABBg/AYPwTqI42iQ/s640/water_props_P1%20%28Medium%29.jpghttp://lh6.ggpht.com/_ZEz8NDGLxu8/TQD8QWGQQZI/AAAAAAAABBk/Uee2d5KLJ1Q/s640/water_props_P2%20%28Medium%29.jpg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Craig]

In the interest of full disclosure, I am a below average skier, at best.

28 off, 36 mph FWIIW.

Not trying to sound cocky in my previous post, I'm used to technical writing.

[DW]

I would suggest that cooler temperatures not allowing the ski to ride as deep will result in less surface area contact and less attainable angle therefore creating the skiing at the buoy and narrow scenario.

Skoke, in your graph, in the vertical or ski perofrmance axis actually have a number or metric attached that mathmatically drove those percentages?  If not, how did you come up with those values.  As I thought about that, I thought that perhaps buoy count v. temp might offer some insight or at least be something measurable.

[Horton]

h2oski1326

Hey dude there are a lot of skiing levels here. Your ideas are as good as any  - you can be as wrong as the rest of us. Everyones ideas are always welcome here.

[Bulldog]

What about the effect of temperature in regards to water clarity? That would have a direct effect on how the water would feel…dirty = slow clear = fast We had to just put another layer of h2o on our backyard rink this am so all of my water is frozen:-(

[Craig]

Horton,

I appreciate that.  Just trying to avoid the post reading like I think I know everything about skiing or anything else.

 

An interesting tidbit about murky water.  Some water/clay/mud suspensions are known as non-newtonian fluids.  In particular, shear thinning fluids. A shear thinning fluid is a fluid in which its viscosity decreases with an increase of shear stress applied to it.  In other words, the harder you push on it, the less viscous it is.  Could explain why some sites with murky water ski really well.

 

[Old MS Accout]

Scoke,

Next time you are with Chet, ask him about this subject. His dad a Nuke physicist and he explains it a whole lot differant then what you would expect. In theory, cold water should ski eaisier.  

[RichardDoane]

my Strada loves the cold water....

[Horton]

I find this endlessly unfortunate but almost every time I hear or read an explanation of skiing biased on science or physics it is wrong.  Maybe this is a broad brush but it sure seems to be true.

 

I always thought that I could not get the rails to engage on heel side (on side) in cold water so I had less angle and everything feels fast. Sort of like an over stiff fin. Ahhh crap lets not go there.

 

On toe side (1/3/5 RFF) most skiers have more ski in the water (tip down) but less roll at apex. On Heel side (on side) most skiers have the tip up a little more but the ski rolls in a more because it is more natural to swing your hips inside the line.  In warm water these two different ski attitudes seem to work. In colder water the heel side approach with more roll but less ski in the water seems to fail.

 

[Old MS Accout]

RD,

Your Strada has never been in warm water has it? 

[scoke]

 

this thread made a lot of sense until people start talking about "toe side/heal side" etc. Confuses the hell out of me as i have a heal on both feet and 10 total toes. my head is spinning after that 1 post!

[Old MS Accout]

I tried to start up a anti dual loc mix in this thread and it failed. I should have waited until January.

[Horton]

Scoke,

Toe Side = Off side = 1/3/5 if you are RFF  /  Genereally less hip counter and more front foot pressure

Is it that hard?

[scoke]

 

Very.

i've got two move across buoys on the left and i've got 3 move across buoys on the right. An entrance gate and an exit gate. that's it. Why complicate it? Simple right?

Why make it harder with: leading shoulder, most confuse it,trailing shoulder, good side, bad side, on-side, off-side, hips countering, countering move, stance, balance, closed to the boat, open to the boat, toe side, heal side, west coast, east coast, old school, new school, COM, COM trailng. yada yada yada. ahh hell my head is spinning. no wonder this sport is made harder than it needs to be.

throw ball, catch ball.

 

 

[scoke]

Some of you guys hit on exactly what I was thinking when I built this graph.

Especially this line: so if all other things constant, a ski is going to perform differently at different water temperatures.

This is the assumption that has to be made as we all agree to the falling points:

Yes there is some physical drop-off in our actual performance when the water temp drops, agreed.

Yes the water feels differently due to the viscosity, faster slower etc, agreed.

My point is going one step further:

When the water temp fluctuates with these high end skis, sometimes our performance improves and decreases due to the SKI.

 My theory follows this line of thinking: There might be a range when the water swings 5-10 degrees and our performance goes down NOT because of our physiological state water temperament but the actual ski reacting to temperature. An example is a warm water/warm summer and a cool rain changes the water temp down into the optimum range. Physically we are still in the same place of performance and the viscosity has changed a bit but now all of a sudden the ski feels more alive, free of the boat and reactive as it’s supposed to.

Perceived optimum is a great term brought up. One persons perceived optimum might be quite different for another but that could be a perception based on the environment of which that person is training. What I am looking for is a perceived penultimate optimum. Is 78-82 degree water the optimum water temp to ski in? That’s the real question.

 

I’ve got three years worth of data on my own skiing but here is a snapshot from this year:

In three years there is plenty of enough sets and buoys actually run for an overall body of work too.

 

Air Temp/Water Temp (+/- 5 Degrees)

Percentage of Sets Skied

65/65 8%

70/70 5%

75/75 9%

80/80 25%

85/85 27%

90/90 11%

90/85 15%

 

So yes primarily I ski in warm water. What brought this discussion up was the fact that as soon as the water temp dropped below 78 degrees myself, and other skiers I’ll bring up later, felt our skis did not perform as well as in warmer water. Once the water broke the 74 degree barrier, it felt like the ski was different. Didn’t rebound as quick, rode higher in the water, and didn’t follow through with its moves. Just a consistent degradation in performance was observed. At this point in time, our air temp was still warm enough to wear a trunk and vest so physically the water temp wasn’t affecting the body, yet.

My point is, once the water temp starts changing temp and our performance goes up and down, IT IS THE SKI!

[Old MS Accout]

Scoke,

Go to page 78 in your journal. Make sure to read the note you wrote to yourself about buying a Strada. You wrote somthing like " MS looks great on that Strada, I need to get one soon"

 

[Horton]

I am with MS. If you want i can sign that Strada for you. That will give you at least 3 balls.

[6balls]

We had a prolonged MN warm spell this year, and I saw water temps in the mid 80's.  At it's peak, Razor1 and I had the opportunity to ski at Trophy Lakes on ZO behind a LXi.  Going in, my 35's were consistent, but not where I wanted them in feel and form.  Razor's 35's kicked butt, but his 38 not where he wanted.  

That day I ripped straight through 38...and crushed it.  Wondered what I should do next, and decided back to 35 and train.  Ran 4 stupid easy passes and called it a set...it was honestly easier than 28 off that day.  Razor goes out and runs straight thru 38 easy, runs 38 again easy, then smokes (and I mean smokes) the first 39 of his life.

Shortly thereafter the temps dropped hard, and we never recaptured the magic of that day, even at the same site behind the same boat.  I always thought it was the optimal water temp that day that helped our skiing.       

[clemsondave]

I've been trying to tell people for a long time to move the fin back in cold water, but no one believes me. Glad I have some allies on here. Right now, though its too frickin cold to come close to the water.

 

MS, how do those tight rubber bindings do in cold water? Some of those things were crazy tight in warm water, can't imagine how poorly they release in the cold. I don't see how dual lock changes in the cold.

 

scoke, i hope it warms up quick or we will have some mighty cold water at Okee.

[RichardDoane]

MS - Western WA lakes rarely get above 75'F, and the Eastern Wa lakes probably never exceed 90'F.  The warmest water I ski in is generally 80'F, it's usually me that creates a problem for my skiing - not the water temp.  Scoke - definitely get a Strada, 6Balls - you should've checked the rope that day !  Clemsondave - I'll try moving my fin back this weekend, and dual lock was designed for attaching things, not releasing

[Dusty]

We got the definitive answer on the water from h20ski, so  how do we quantify the skis' change(s). Some materials change a lot w/ regard to temperature- some not so much.  Most  plastics for the  most part get stiffer with lower temperatures. Does that change ski flex enough to alter performance?  Not to make a pun, but- I think once your feet are numb the performance falls off...  i know I do.  Hate those ice cream headaches!

[Old MS Accout]

CD,

I have never had issues with comming out in any temps but I rarely push it during the cold water season. 28/32 off back to back is the ticket to staying up top. Getting out of the binding at the end of the set is what sucks. Hot water showers or coolers full of hot water are a must. I tried some Stradas at the end of the season and they felt pretty good. I am right in the middle of 10-11 and it would be great if they had a 10.5. I am going to try the new D3 binding also so I may stay in rubber if they feel good. 

    

[scoke]

 

interesting turn of events in these last few posts. it doesnt make sense for me to buy a cold water ski when, looking at my stats, i ski in warm water between 78-87% of the time.

My last Goode worked very well for me. I've got 10 sets on this one and have run more buoys on it than the other one. It's working. I don't change the fin in the current cold water, just change the degree angle and thats it. If i am skiing in cold water it's for muscle maintenance and muscle memory not to try and run a PB.

 

 If I moved north of the I-10 corridor i'd consider a cold water ski.

For years we have talked about how our performance starts to drop when that temperature drops. I polled between 7-9 Goode skiers and they pretty much felt the same thing. As soon as that water temp drop, so did performance of the ski and not the skier. Strong statement indeed but it sure says something about the skis performance in warm water!

Anyone else feel the same way about their Goode? Anyone else on other brands?

 

[bmiller3536]

I think the reason alot of skiers performance drops when the temperature drops is due to the how frequent they are skiing. Once daily savings hits and my evening skiing is cut out during the week my buoy count instantly goes down, not because of the cold water but because I am only skiing on weekends above 47 degrees. Plus I hate falling in cold water, than having to sit and freeze while the boat turns around. So once things start to get out of control I shut it down and wait for the next pass

[6balls]

Richardoane, we bring our own rope/handle when we train there...a legit masterline that we also use behind Razor1's MC.  Was a wicked day of skiing, one of my highlights of the summer.  His successful 39 is the only successful 39 I have ever pulled, too.

You should ask MS about checking ropes while judging!/vanillaforum/js/tinymce/jscripts/tiny_mce/plugins/emotions/images/smiley-wink.gif

[Old MS Accout]

Scoke is experienced with my rope rangeling expertise.

[Ed_Obermeier]

Clemsondave wrote "I've been trying to tell people for a long time to move the fin back in cold water, but no one believes me..."

Posted this earlier FWIW.  At the end of the season after the water temp had dropped significantly and our skis weren't working as well, a buddy of mine I ski regularly with and I tried the fin forward/backward adjustment for the cooler water temp for the sake of experimentation.  I went forward (Strada), he went back (MPD), my ski was better his was worse.  Readjusted his fin forward and he skied much better and agreed that forward in cooler water was better than back.  Of course we're only 28 - 35 level so maybe that factors in?  Different strokes I guess.  Very confusing...

Ed

[slow]

A 66" Stada worked great for me below 70 degrees and the 67"  better above. It felt like I was dragging around the 66" in warm water which makes me think warm water skis slower.

[disland]

OK, so forward works better in cold water. We have come to the same conclusion here in Princeton. Water temp about 45 right now. Question we had yesterday- What will the indication or break down be when the fin has been moved too far forward?

[Steven]

I've been moving my fin forward, making it shallower and longer for cold and the opposite for warmer water (boots move forward and back to follow the fin) and it has worked real well for me but now Rossi has an article saying exactly the opposite.?? I know what I'm doing has worked real well for me, but that Rossi article has me real confused! I guess I should try it to find out for myself. 

[Steven]

Has anyone tried a Johnny Horton fin a Strada? If so what were your findings?

[Bruce_Butterfield]

Scoke - you need to get on the water below 70F while you're still young! How does that Goode do at 33F? You may need to go to southern Canada to find out. Its NOT the ski. Its that you and the ski do the vast majority of your skiing in the LA hot tub. Its only natural for us to adapt the our technique and the ski tuning to the conditions we ski the majority of the time. That dang Guassian curve hits again. Yes, the water temp makes a "difference", but we naturally adjust both the ski and our bodies to when we ski the most.

 

h2oski1326 - good stuff. Maybe someday, someone will quantitativly determine the problem is on the dry side of the ski!

 

BMiller Wrote "I think the reason alot of skiers performance drops when the temperature drops is due to the how frequent they are skiing."

Nail, meet head.

 

PS, I'm with you on the heels on both feet and 10 toes. I think Horton is mutated somehow.

[h2odawg79]

There are endless variables, speculation and perceptions.

My perception is; This thread is about  a particular Noun.  Def; Person, Place or thing

So, the Real question (the post title) @ hand seems to be whether a ski (a thing) actually reacts to temps? (all)

If so, #1. What is the actual reaction to colder water? and #2. how can I counter any negative effects resulting from the Ski's reaction to these colder temps...

IMO,  People & places really need to be rationalized in a seperate thread...

(Just trying to get back to the real question)

 

FWIW, THERE AIN'T NO TOE SIDE/HEELSIDE IN SLALOM! -nothing ambiguous about that...http://www.ballofspray.com/vanillaforum/js/tinymce/jscripts/tiny_mce/plugins/emotions/images/smiley-wink.gif

 

[eleeski]

Toeside is way different from heelside. A bigger difference than hot vs cold water.

H2oski, thanks for the insight. Now I know it's not just me being wimpy in the cold. There is a real physical difference.

Maybe I need to build a thinner ski for the cold. Who am I kidding? Ham said it for winter waterskiing. I'm off to Tahoe for some snow skiing.

Goode snow skis rock!

Eric

[Razorskier1]

Seems like there are a lot of other variables, including how much sediment is suspended in the lake.  I ski a deep, spring fed public lake and the water feels "fast" and "hard" even when it warms up in the summer.  Spring and fall I ski in 45 degree water, summer it might get to mid-70s.  It is very easy to ski and get wide if you just relax and let the boat do the work.  Going from that lake to any of the local man-made ski lakes, the water on those feels very "slow" and "soft".  My ski sinks in and feels like it is carving through the water more.  Some of that is temperature and water depth, some of it is sediment (I think).  Whether it is because of temperature or sediment, my best scores are on warmer or more sediment filled waters.  They feel easy after skiing on my lake.

[Craig]

I will preface this post by saying first, yes, I am a nerd. 

If you are not, and do not wish to filter through nerdy things, here is a brief

conclusion.

Outcome from Scoke’s

data: 

 

Scoke perceives his skiing performance to be optimized in

water temperatures he practices in this most.

 

Extended Conclusions:

 

Slalom skiing is very sensitive to changes in water temperature.  A particular ski will act differently in

different water temperatures.  Over time,

a skier adapts to the temperatures he/she frequents the most.  Thus, a skier will likely perform the best in

temperatures he/she is the most used too.

 

Some more details

(the nerdy bit):

 

Here is an overlay of scoke’s original plot (in blue) with

the temperature data he provided in green.

 

http://lh4.ggpht.com/_ZEz8NDGLxu8/TQeowiWGP8I/AAAAAAAABB0/Wd6eCSRhSLY/s640/Scokes%20Data.png

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I generated this plot by converting scokes temperature data

into a proportion (a percentage).  I did

the same with the perceived performance data from the first plot in the thread.

 

The peaks of the two plots seemed to correlate sit near each

other so I thought I would try and quantify how related the two sets of data

may be.  I did this using a statistical

method called the correlation coefficient. 

This is a method for determining how related two sets of data are.  If you are interested in the details, do some

reading here:

 

http://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient

 

My analysis showed that there is at least a moderate

statistical relationship between the perceived performance and the frequency of

skiing at different temperatures (I calculated a number of 0.73 at 0.05 level

of significance).  So from this I can

come to the conclusion that scoke perceives his skiing to be at its best at the

temperatures he spends the most time at.

 

Extending those conclusions a reasonable hypothesis would be

that everyone skis better in the conditions they ski in the most (including

temperature, water sediment quantity, wind speeds, speed control, etc.). 

 

These don’t seem like ground-breaking conclusions but I

think hold some valuable insight. 

 

 

 

[scoke]

 

couple of points:

if you read my original post, i dont actually talk about my performance. Just the skis.

• I am talking about what i feel in the ski.
• The ski feels not as great in cold water as the ski is greatly affected by water temp swings
• I polled 7-9 skiers all riding goodes, all feeling the same things as well. Also the skiers are experienced into deep shortline  up to 38/39/41
• An assumption is made and rightfully so as the skiers are experienced and know their bodies well enough, that this is usually at the same lake and the skier is with the same physiogical characterstics

[Craig]

OB,

I agree, lots of variables to plot.  A big assumption is that all of the human factors are constant.

I think the conclusion is insightful because I am not sure if everyone even knows the conditions they ski in the most, I know I don't.  Some keep a journal with lots of information but how many do that or actually review the journal looking for trends.

Scoke,

I know you were just talking about the ski.  However, if all human factors are constant what you feel on the ski would lead directly to performance.  In that sense what you feel from the ski and what your performance is would be one in the same.  It makes perfect sense to me that an experienced skier likely knows how the ski feels in different conditions so the buoy count may not change a lot given a variety of temperatures.

Again, I'm not trying to say this is how it is for everyone all the time no question.  I have drawn conclusions based on minimal data, one of the data sets is a perceived set of data so any conclusion is really a stretch.