fredag 19 februari 2010

Building a cheap, lightweight, Paris-skipulk

In january the entire family went on skiing vacation to Orsa Grönklitt in Dalarna, Sweden. From experience I knew that transporting the children back and forth to the slopes can be a real chore. Especially when the children are tired after a long day. Having a pulk to pull all the equipment can be a real help. It's also real nice to be able to put the small children in the ski pulk when they decide they've had enough of cross-country skiing several kilometers from home. Last, but not least, I of course saw this as a chance to get an interesting new piece of gear.
Since I don't get a chance to use a skipulk that often I didn't want to spend too much money on it. I don't have as a goal to go on a long arctic expedition with 100kg either, so I figured I didn't really need the robustness of a Fjellpulken. I also had a look at the second-hand market. It is pretty good for pulks here. If you are not worried about weight it is quite easy to find old used Segebaden wooden pulks of good quality. These weigh quite a lot though and they require some care to maintain. There had to be a better alternative.

The Paris Expedition sled
After some googling I found the most authoritative site on skipulks: www.skipulk.com. The nice thing about this site is that they provide an excellent ski pulk PDF-book with detailed descriptions on how to build your own ski pulk. This book, and many others sites, recommend the Paris Expedition sled as a good starting point for a do-it-yourself project. The Paris sled is cheap (around 30€), light (2,2kg) and very durable. It also has good attachment points for packing straps and ropes for pulling. I quickly ordered one from globetrotter.de as there were none in stock at the local retailer kgoutdoor.se.
The Paris Expedition Sled

The hauling system
The pulk book contains a number of different designs for the critical pulk hauling system ranging from very simple designs suitable for flat terrain, to heavy duty systems for alpine use. I didn't have much time for the construction so I made a hauling system loosely based on the "Zinsard"-design. I figured it would be good enough for my purposes. I was not going to use the pulk on rough and steep terrain. It would be used mainly on prepared cross-country tracks.
The hauling system was made from 20mm electrical wire conduit (VP-rör)

The advantage of using plastic conduit is that it is very easy to work with. It is also cheap and you can get angle parts and joints to easily create constructions. It is also very flexible will not hurt you if you fall. The opinions vary on how robust the conduits are, some say they are better than bamboo, some say they are very fragile. For my purposes they worked well. To be on the safe side however, I also reinforced the poles with duct-tape, so that they would not splinter in a dangerous way if they broke. This probably makes them stronger too. The poles where attached to the the pulk by using packstraps through the grommets on the pulk. 
Using conduit joints, the poles can be disassembled for easier transportation

I also added joints so that the poles could be transported more easily. This was done using standard plastic joints for conduit. To keep them in place I also drilled a hole for a nut and a bolt. Later on I also drilled a hole so that the hauling rope went through the poles and all the pull forces where taken by the rope. This is quite useful since the joints don't need to be as strong then. If the poles will break it is also always possible to pull the pulk using the rope.

 A custom hipbelt was quickly sewn

I didn't have any existing hipbelt to use as a harness available, so I sewed my own. It was done in about an hour using nylon, some foam pad, and webbing. I made a mistake however and made the belt to short. It needs to have more padding on the stomach side as well. As attachment points I sewed in some metal D-rings. I did not place these in a good way however. They should be more on the sides so that the poles attach to the side of the body. To attach the poles to the belt I drilled a hole through the poles and threaded to loops of nylon cord through them. These loops could then be attached to the D-rings. This attachment system worked OK, but there is room for improvement. There was too much play between the poles and the hipbelt. Despite these shortcomings the belt worked perfectly OK for the loads that I was pulling.

Field testing
The pulk was mainly used to transport the kids back and home to the slopes. However, I also stressed the hauling system to some degree as I climbed the downhill slope all the way to the top and successfully skied down on a pretty steep slope with around 20kg of young son in the pulk. It worked very well, but I'm not sure how the poles would have handled a fall. I also tried going through the kids "Bumpy ride" training slope as well. On these occasions I could really feel the force of the pulk pushing me in the back, but it worked.
Going down the slalom slope at full speed with Simon lying in the pulk

One situation that didn't go so well however was if I needed to pull the pulk through difficult terrain. Part  of the difficulty could have been that the children were sitting up and produced a top heavy load. Anyway I felt that stronger poles could have been good in that situation. With two kids the pulk was pretty heavy then, probably about 45kg.

All in all, I'm very pleased with the Paris Pulk and the homemade hauling system also worked very well for what it was designed for. It made our winter vacation with the kids so much more fun and a lot easier too.
Children sleeping in the pulk after a long day at the Orsa Grönklitt Zoo

3 kommentarer:

  1. Great we have found the same outstanding pulk!. I just got the hood sorted - pictures at http://www.utsidan.se/forum/showthread.php?p=529348
    Greetings from Visby.

    SvaraRadera
  2. I saw you mention that you also built a children's seat for this pulk. I'd love to hear more about that or see what you built it out of.

    SvaraRadera