Saturday, March 15, 2008

Improvements to the N7UN Sled:

A number of folks have inquired about the N7UN sled that I’ve been using for carrying my backpack on snow during winter hikes. The use of a sled significantly reduces the amount of work during the hike since the backpack is carried in the sled which slides almost effortlessly on snow. Added benefits are the reduction of “wear-and-tear” on the body due to carrying a 35-45 lb pack on your back over 3-5 miles and climbing or gaining a lot of elevation.

Coming down hills is more challenging although. The sled “nips” at your heels since it's sliding down hill. I was holding my ski poles behind me against my pack to control it. I later added some aluminum brackets to the sled and drilled a hole in each bracket just larger than my ski pole tip. The idea was to put my ski pole tips in the bracket holes thereby providing a tighter connection with increased positive control of the sled during the downhills.

This worked great on the trip to Blue Mtn recently. In fact my ski poles would “wedge” themselves in the bracket holes thereby allowing me to lift the front of the sled which is very helpful in crossing creeks or trail obstacles. The problem however is the wear-and-tear on the ski pole tip due to being wedged in the bracket hole. During the Blue Mtn trip, after several hours of downhill control of the sled by use of the ski poles, the tips broke off. It seems on my Black Diamond poles, the tip is connected to the aluminum shaft by a hard plastic shell which becomes the weak point and eventually cracks and then breaks off.

Joel Miller, W2TQ, my winter hiking friend, suggested that I might adapt some sort of ball joint to connect the ski pole to the bracket. Good idea! So a google search later for “small ball joints” I found a potential solution at Small Parts, Inc. in a ¼” thread swivel ball joint with an overall length of 1-13/16”. I then threaded the ski pole shaft end to fit the ¼” thread, bolted the ball joint to the bracket and screwed in the ski pole shaft and “eureka!” a positive control to the sled with a swivel joint. The sled front end can now be lifted to clear terrain obstacles and the ski poles act like arms to the sled for very positive control during steep downhill sections of a descent.

Although I haven’t tested this improvement yet in actual snow/hiking conditions, it should work great. Now I can control the sled during the downhills, and still have the rope-to-waist belt for pulling the sled during the uphill sections of the hike and my poles free from the sled to assist in the uphill climb.

Until you try a sled to haul your gear, I can’t tell you how much less work is required which in turn results in a much more enjoyable winter hike over longer distances.

The Small Parts, Inc. part number for the swivel ball joint I used is: BJS-06-01 and costs $4.75 each. An engineering drawing of the part can be seen at: Hopefully these ideas can make your winter hiking more enjoyable!

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