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Skiing the Beach

post #1 of 15
Thread Starter 

I'm hoping to try some different types of cross country skiing this season, and was thinking since I live near the ocean maybe it wouldn't be too crazy to just get a cheap NNN Classic setup and hit the beach for some practice. Did a search here and didn't find anything about that, but not surprisingly I'm not the first to have this idea...

 

 

Being a XC newbie seems like it wouldn't be a bad way to get familiar with the motions and get some good exercise in the process. And who doesn't like going to the beach?  ;-)

post #2 of 15

Fwiw,  3-Pin is lighter and easier to clean sand out of.

post #3 of 15
Thread Starter 

What exactly is lighter? The bindings? (NNN bindings seem pretty minimal.) The boots? I guess 3 pin is a more open design, doesn't have the nooks and crannies for the sand to lodge in.

 

I figured NNN might be a good way to go for flattish (meadow/forest) cross country in actual snow, so if it wouldn't F it up completely then it could be usable for beach skiing.

post #4 of 15
Quote:
Originally Posted by jc-ski View Post

What exactly is lighter? The bindings? (NNN bindings seem pretty minimal.) The boots? I guess 3 pin is a more open design, doesn't have the nooks and crannies for the sand to lodge in.

 

Both, unless we start talking about boots with thick lugs (>15mm) and mountaineer-grade bindings with thick solid lifters underneath. 

 

Quote:
Originally Posted by jc-ski View Post

 

I figured NNN might be a good way to go for flattish (meadow/forest) cross country in actual snow, so if it wouldn't F it up completely then it could be usable for beach skiing.

 

What I'm saying is: use your snow rig for snow.   

 

Find a second super-cheap setup that is slightly long and on the stiff side for your weight and use /that/  on the beach... and if it happens to be someone's antique-looking  3-pin setup then that's OK.

post #5 of 15
Thread Starter 

Good advice, as always. Thx.

post #6 of 15
Thread Starter 

I tried sand skiing on a Lake Tahoe beach several weeks back using long skinny waxless classic skis with NNN bindings and light boots. Didn't get much glide, (no extra distance after the push), but they did slide just fine on each stride. This was on dry, larger (not fine) particle sand. It worked well enough that I'm going to try it some more on the beaches down around San Francisco now that the ski season is over for me. I like to hike, but don't really care to run any more - skiing on the beach will be a nice way to push things aerobically without putting a lot of stress on the bod - I will continue to do more of that next season in the bumps!   ;-)

 

Oddly enough this morning I got an email about a "SandSkiing" Meetup group that is focused on cross country skiing on the beach, so I guess there are other nut jobs out there. Like these gals...

 

 

How NOT to do it...

 

 

Whatever you choose to do in the off-season, stay classy (and healthy), EpicSki!   ;-)


Edited by jc-ski - 4/21/14 at 9:51am
post #7 of 15
Thread Starter 

First day out for a half hour...

 

 

Not a bad way to get some exercise - definitely got the heart pumping and worked up a sweat - lower calves a little tight after - will be interesting to see how things feel tomorrow.

 

Still not really getting any glide on the sand, and worse as things got wetter (edge of surf). If anybody has any suggestions about wax or other prep to improve glide on sand I'd be interested.

post #8 of 15
Thread Starter 

Hmm, the skis I was using have a waxless (scaled) base. Wondering if perhaps a plain base might be a better way to go on the sand? Will have to check the thrift stores for a cheap pair to experiment with.

 

Guess XC skier Bill Koch might have started this beach skiing thing some years back...

 

 

There's a little blurb bottom of this page, but I haven't been able to find any video of him in action...

 

http://www.crosscountryskier.com/2005-06/oct_05_features_voices_from_past.html

post #9 of 15
Quote:
Originally Posted by jc-ski View Post
 

First day out for a half hour...

 

 

Not a bad way to get some exercise - definitely got the heart pumping and worked up a sweat - lower calves a little tight after - will be interesting to see how things feel tomorrow.

 

Still not really getting any glide on the sand, and worse as things got wetter (edge of surf). If anybody has any suggestions about wax or other prep to improve glide on sand I'd be interested.

 

 

Quote:
Originally Posted by jc-ski View Post
 

Hmm, the skis I was using have a waxless (scaled) base. Wondering if perhaps a plain base might be a better way to go on the sand? Will have to check the thrift stores for a cheap pair to experiment with.

 

Guess XC skier Bill Koch might have started this beach skiing thing some years back...

 

 

There's a little blurb bottom of this page, but I haven't been able to find any video of him in action...

 

http://www.crosscountryskier.com/2005-06/oct_05_features_voices_from_past.html

 

 

Don't forget he's on carbonate sand.

post #10 of 15

Related to this thread, you might have seen the pop-sci rewrites of this announcement:

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.175502

 

Quote:
We show experimentally that the sliding friction on sand is greatly reduced by the addition of some—but not too much—water. The formation of capillary water bridges increases the shear modulus of the sand, which facilitates the sliding. Too much water, on the other hand, makes the capillary bridges coalesce, resulting in a decrease of the modulus; in this case, we observe that the friction coefficient increases again. Our results, therefore, show that the friction coefficient is directly related to the shear modulus; this has important repercussions for the transport of granular materials. In addition, the polydispersity of the sand is shown to also have a large effect on the friction coefficient.

 

Try right after or during light rain?

 

The surface area of our skis is too low, by a factor of 3 or more, to glide on top of sand with actual water film above the grains.    In order to have the float area of even the most rudimentary skimboard the skis would have to be 270cm+ long and 80mm+ at the waist.     Short of engineering some sort of air-entrapment tunnel structure, semi wet is our best option.      The polydispersity bit at the end refers to the distribution of grain sizes; that's not something you can control other than by picking which beach to glide on.


Edited by cantunamunch - 5/1/14 at 7:12am
post #11 of 15
Thread Starter 
Quote:
Originally Posted by cantunamunch View Post
 

Don't forget he's on carbonate sand.

 

I'm not a Geologist, but isn't all ocean beach sand carbonate sand?

 

Quote:
Originally Posted by cantunamunch View Post
 

Related to this thread, you might have seen the pop-sci rewrites of this announcement:

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.175502

 

Try right after or during light rain?

 

Not sure how salt water impacts glide. The salt in the water is in essence I guess something that could provide more friction?

 

In any event to recap my two sand skiing experiences so far have been on a Lake Tahoe beach - mostly very dry sand, larger particles - and Ocean Beach in San Francisco - much finer sand with varying degrees of wetness. I would have to say the glide, though not considerable, was marginally better on the dry lake Tahoe sand. At Ocean Beach whatever glide there was diminished as I moved from the dryer sand further away from the surf, and the more I got into the thin layer of water at the surf's edge the more I bogged down.

 

Again, I'm thinking the waxless pattern on the skis I was using probably wasn't helping. And I'm starting to inline skate regularly again, so I am going to try and find a cheap pair of XC skate skis. If I can figure out how to get some glide I'd like to do a combo of classic and skate style skiing when on the sand.

post #12 of 15
Quote:
Originally Posted by jc-ski View Post
 
Quote:
Originally Posted by cantunamunch View Post
 

Don't forget he's on carbonate sand.

 

I'm not a Geologist, but isn't all ocean beach sand carbonate sand?

 

 

Not even close to 'all'

Quote:
 

Not sure how salt water impacts glide. The salt in the water is in essence I guess something that could provide more friction?

 

The mechanism under discussion in the article wouldn't really be affected much, unless there was a significant change in surface tension.    They're trying to eliminate pushing of sand in front of the gliding 'sled'/ski by creating water bridges between grains.

Fortunately, surface tension is something we can observe pretty directly by looking at the curvature of a given water sample as it meets the walls of the container.   You can do that experiment yourself, with just an eye dropper and a macro-capable phone camera.


Profiling the front of the ski so it provides more gradual taper, kinda like the old 'elf shoe' XC skis would do, might help.      

Quote:
Originally Posted by jc-ski View Post

 

In any event to recap my two sand skiing experiences so far have been on a Lake Tahoe beach - mostly very dry sand, larger particles - and Ocean Beach in San Francisco - much finer sand with varying degrees of wetness. I would have to say the glide, though not considerable, was marginally better on the dry lake Tahoe sand. At Ocean Beach whatever glide there was diminished as I moved from the dryer sand further away from the surf, and the more I got into the thin layer of water at the surf's edge the more I bogged down.

 

That all makes sense in view of the article - larger particles will resist being pushed forward by the ski, and will not tend to create piles as they're pushed.    You don't have anywhere near the surface area required to float on water, even skimming-wise, so the more water you were in the slower it went.     

post #13 of 15
Thread Starter 
Quote:
Originally Posted by cantunamunch View Post

 

That all makes sense in view of the article - larger particles will resist being pushed forward by the ski, and will not tend to create piles as they're pushed.    You don't have anywhere near the surface area required to float on water, even skimming-wise, so the more water you were in the slower it went.     

 

OK, all good info, thx.

 

I know they're on different sand, and different skis, and have no idea what if any wax they're using, (or how much of a difference that might even make), but the gals in the first video in post #6 are getting a LOT more glide here than anything I've experienced, and they are on fine sand and in the wet part if not all the time...

 

http://youtu.be/xquP1GjD658#t=55s

 

http://youtu.be/xquP1GjD658#t=1m10s

 

Any ideas?

 

Perhaps I can track them down and find out how they prep'd their skis.


Edited by jc-ski - 5/1/14 at 1:00pm
post #14 of 15
Quote:
Originally Posted by jc-ski View Post

 

OK, all good info, thx.

 

I know they're on different sand, and different skis, and have no idea what if any wax they're using, (or how much of a difference that might even make), but the gals in the first video in post #6 are getting a LOT more glide here than anything I've experienced, and they are on fine sand and in the wet part if not all the time...

 

http://youtu.be/xquP1GjD658#t=55s

 

http://youtu.be/xquP1GjD658#t=1m10s

 

Any ideas?

 

Perhaps I can track them down and find out how they prep'd their skis.

 

Hahahaha.

 

Those women are STRONG.    As in far, far, far stronger than us weekend warriors.    As in "almost mutants".    For me the particularly telling moment is at ~1:46 when they're across the beach.   They're trying to make it look "natural" esp. as a finish, and as soon as they stop striding they overbalance and almost fall over from friction drag.

As far as prep,  I'm betting they used the exact same "prep" as they used for the warm, dirty snow they're on - i.e. no wax at all and simple flat scraping nose to tail.     Even if you didn't believe Kuzmin's  over-reaching generalizations about all conditions and all snow, he did do a reasonable job of showing that that type of prep is darn good for that specific sort of snow.

post #15 of 15

Those women are STRONG.  oh my.

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