Friday, January 11, 2008

Anatomy of a Sled

This has been a great week of training. A little new snow has led to some of the best skiing yet this year (I've XC skied 40 miles this week as well as the usual 80+ miles of running) and I've had a chance to get out a couple times with my sled full of gear. Today was a very good test run with my sled. Pulling 30 extra pounds is just plain hard work but as I make small adjustments to my sled it continues to become slighter easier.

I've had a few people inquire about the specifics of my sled, and I'm sure it will evolve further before February 24th, but here's a breakdown of what I'm pulling behind me right now:

The sled itself is a basic $10 kids sled that I bought at the local drug store:

I've attached a pair of youth cross country skis (110 cm) to the bottom to reduce friction and allow it to slide easier. The blocks of wood raise it up for a bit more clearance in case there is some depth to the snow:

I laced some cordage around the perimeter of the sled and attached webbing and buckles to this that I use to secure the load in place:

Also in the above picture you can see a strip of velcro all the way around the perimeter of the sled. I am currently sewing together an old rain poncho to form a cover that will velcro over my load and zip in the center. This will keep any loose or falling snow from filling up in the sled.

Here's a picture with some gear loaded in it:

The pole is 2 cross country ski poles (160 cm) that are clamped together to form one pole and the lower 18" of each pole is bent (using a conduit bender to avoid kinks) outward about 4 inches so they attach to the front outer corner of the sled:

At the top of the poles I have attached two 18" pieces of flexible tubing which then attach (with duct tape) to the harness which I built out of webbing, an old z-rest sleeping pad, and duct tape. Right now I have vinyl tubing on there but I'm going to try to replace it with silicone tubing so it doesn't get so stiff (and potentially breakable) at cold temperatures:

The poles are attached to the sled with perlon cordage that runs through the length of each pole and ties through holes drilled in the sled.

The end product is a sled with great control (unlike my system I used last year this sled is almost impossible to flip over and it tracks perfectly straight behind me no matter how uneven the trail is). I'm still tweaking it a bit to try to minimize the amount of shaking where it attaches around my waist but my new addition of the flexible tubing has helped greatly with this. I'm hoping silicone tubing will be flexible enough to absorb all of this shaking but not so flexible that it causes less control of the sled.

In all it's a pretty basic setup but it has taken me more than a year of testing and brainstorming to get to this point. I don't even want to know how many hours and how much money I have put into this thing. Almost every modification I have made evolved from an earlier attempt at the same modification that didn't work out so well. I've tried 3 different pair of skis, 2 harnesses, and 3 or 4 different pole systems. Hopefully the snow cover that I'm currently making works out ok on the first try because I've already spent about 2 hours working on it and I still have to sew a zipper in it and sew the velcro around the edge of it. I don't really want to deal with making a new one.

In the sled I'll be pulling all the gear to survive in interior Alaska in February:

  • negative 20 degree down sleeping bag
  • bivy sack
  • insulated sleeping pad
  • stove
  • fuel
  • cooking pot (mostly for melting snow)
  • extra clothing beyond what I'll be wearing (wool socks, liner socks, down jacket, waterproof/windproof shell, neoprene socks, down booties, neoprene booties, extra base layer, expedition weight thermal underwear, insulated ski pants, mittens, goggles, ski mask, expedition weight ski mask)
  • sled repair kit
  • multitool
  • small first aid kit
  • foot first aid kit
  • water (up to 6 liters at times)
  • food (up to 3 or 4 days worth at times)
  • basic toiletries (toothpaste, toothbrush, toilet paper)
  • lighter
  • emergency firestarter
  • chemical hand and foot warmers
  • extra batteries for headlamp, camera, and mp3 player/radio.


Anonymous said...

Hey Geoff. Excellent workmanship on that sled of yours. You transformed a child's toy into a sophisticated survival vehicle. Hopefully it'll hold together just long enough to get you where you want to go.

Good luck with your training and thanks for posting the photos and sled contents. I'm in awe of what you're attempting to do.

Best regards, Al

Anonymous said...

How about spending another 10 bucks for another sled. Turn it over upside down and use it for the top.

Geoff said...

i thought about the second sled on top, but it wouldn't be tall enough for the gear i'll have. so then i thought about a longer sled so it wouldn't have to be loaded as high with gear but that would mean getting new skis, and redoing almost all of the other modifications i made... and the larger sled would probably just encourage me to take more stuff that I really don't need. a sled on top would be cool though, if it tipped over i could just keep going with the top sled now on the bottom :)

Anonymous said...

I'd be concerned about the cold killing the batteries so far away from your body heat. To get around that in the past, I made a camera case out of cheap closed cell foam (craft store) which velcroed shut. I stuck a big chemical warmer (it was labeled as for the lumbar region) in and closed it. They burn more slowly if they're not exposed to air, so one of those lasted 24 hours and my camera (and the other batteries I kept in there) stayed perfectly fine.

Doug said...

Nice job on the sled Geoff! I built my own sled for winter camping several years ago. I have to say you have some interesting design features. Looks like it will do the job.

Derrick said...

Hey Geoff,

Just had a couple of more quick questions about your pole system...

You said you used perlon cordage, fed it through the poles and attached it to the sled. Just wondering how you attached it at each end? Did you use a loop bolt(?) on the sled or something else?

Also, did you feed the silicone tubing over the poles and clamp them? Was this secure enough? How did you secure the rope through the tubing?

I had thought of using coated cable (clothesline) through the poles, but it wouldn't have as much give I guess would be the drawback.


Derrick said... the way, I've been pouring over the photos of your sled with a magnifying glass!

Derrick said...

thanks again for all the advice Geoff. I think I've got things set the way I want them.

Anonymous said...


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