Single Handle Pulk Design

[DayTrip]

I've been reviewing all the articles on VFTT about building a pulk these past few weeks and have finally bought my Paris sled and some hardware and am getting ready to build. One question I wonder about is why no one has built/designed a pulk with a single pull handle instead of the double handle construction. It would seem that a single tube would allow it to function more like a trailer (i.e. pivot around obstacles) and possibly make it easier on narrower trails. My first thought was that having one tube while descending would drive it into the small of your back but that could be easily avoided by making a u-shaped, padded bracket to distribute the force to the hips. Having a pivot at the harness and the sled should make it "turn" better than the instant feedback of the two pole set up.

I'm building mine the conventional way but I'm wondering if anyone has tried a single pole design. I'm sure there is a reason no one has done it but that reason escapes my admittedly poor mechanical aptitude. Anyone ever try this? Never used a pulk so I suppose some first hand experience would enlighten me to the obvious problems. I'm not worried about flat/easy grades but on more moderate grades with trees to avoid, rocks, etc I'm wondering about the handling capabilities of these set ups, especially descending.

 

[bignslow]

I'm not worried about flat/easy grades but on more moderate grades with trees to avoid, rocks, etc I'm wondering about the handling capabilities of these set ups, especially descending.

We pulled on two trips: Abol to Chimney Pond and Abol to Daicy Pond, if you're trying to do anything steep/twisty/etc... you're going to have a bad time.

My two cents on pulks (after having built a set of commercial quality ones using fiberglass rod and metal fittings for all the connections) is this:
1) Nobody is used to pulling pulks, you're going to have a whole new set of muscles that are sore
2) Pulks practically beg you to overpack. I sewed some duffle bags out of old tent flys to keep our gear dry and when I calculated the volume of the paris sled (to a height of 8-10", I can't remember), it was something like 130L of volume. If you're not careful, it is easy to fill that whole volume with "stuff", just because you can.
3) The best configuration for the pulk poles is crossed two poles. the reason for this is that you're forming two triangles between your pack and the pulk. That triangle is going to hold its shape better (cross slopes, around obstacles) better than a rectangle (turns into a parallelogram) or a single pole (which can just sweep in an arc in any direction. With our pulks in this configuration, we were able to have our sled track behind us on cross slopes where the other members of our party had slid down. Similarly, when negotiating trail obstacles, a twist of the hips (in the opposite direction of the turn) would swing the pulk around smaller obstacles, while larger obstacles would require a "tractor trailer turn".

 

[bikehikeskifish]

Where'd you get the 6-7' fiberglass poles? I can only find 4' around here...

Tim

 

[bignslow]

Where'd you get the 6-7' fiberglass poles? I can only find 4' around here...

Tim

http://www.kencove.com/fence/Fiberglass+Posts_detail_F12-4SG.php

In order to get my shipping-per-unit costs down, I actually built three full sets. Shipping from both Kencove and McMaster were both reasonable regardless.
If you're ever in the Syracuse, NY area, I have a full set of (partially threaded) fiberglass poles which could easily be made into a 4th set (hit me up on facebook for more details about both the poles, and the possibility of borrowing our existing pulk).

EDIT: Here is my bill of materials (and costs) from a few years ago:
https://docs.google.com/spreadsheets/d/1l5dRrf-yWn5OwaW6CccQ7xV1ELxGacsG3clLzRhCJ44/edit?usp=sharing

The skipulk.com folks used to publish a "how to" manual (which I just found on another website: http://www.ccsam.ca/wp-content/uploads/2011/09/pulkbook.pdf). I built the pulk listed in chapter 11.

 

[bikehikeskifish]

I have the kenco link from the same sources as you... wanted to get things locally, if at all possible.

Tim

 

[Tom_Murphy]

I have two cross ties so that the poles are shaped like a "two rung ladder". I glued over sized pipes tees to the poles.

This makes for a very rigid set-up that really helps when side-hilling. The far end of the pulk can be moved in a full circle by spinning in place. The larger turning radius can be a problem.

I use my pulk with snowshoes and I was able to use much shorter poles. Basically, measure your stride and cut the poles so that the back of your shoes or skis don't hit the pulk.

I use two backpacks and distributed the weight about 30 - 70. When it gets steep [uphill or downhill] I swap up the packs - I put the heavy backpack on and the lighter one in the pulk.

 

[bcskier]

The pulks I have used have evolved over the years as one design gave way to another. I have also done trips with other sled users and have had a chance to observe their designs. The earliest were red Coleco sleds which were pulled with small diameter rope. The design is ultra simple but rope invites the sled to run up into the back of your legs at the bottom of hills, it's hard to control the sled on corners and there is alot of herky jerky feedback. That evolved into poles instead of ropes but the ends of the poles were free to pivot where they attached to the sled. The disadvantage as bignslow says is the parallelogram effect where you can be skiing down a slope and the sled is out to the side not tracking in your line inviting collision with trailside trees and eventually resulting in a trailside repair job. I've borrowed a commercial sled (Mountainsmith I think) that, being fiberglass and heavier, was at a disadvantage compared to a plastic sled on a long flatish ski out. The two advantages I did discover to the commercial sled design were tracking ribs on the underside and a hinged u-shape attachment for the poles. I copied that on my latest sled design and have been happy with it ever since.

One friend did have a single attachment type of "sled." It was actually a plastic tube which looked like a big duffel bag with a funnel on the end. A length of webbing cord was riven through the hole in the plastic funnel. That was encased in a section of equally long clear polyethylene tubing. The tubing did impart a bit of stiffness to the cord, not as much as a pole, but the ultimate theory behind the system was that whole cylinder was free to rotate as it was pulled and you never had to worry about your load being upset by the terrain. The thing was commercially produced somewhere, but I've forgotten by whom. I think it would be a practical design in regions with soft deep snow. It would trail best if it was riding in snowshoe track. During the one trip I watched it in use we were skiing in to Perkins Notch shelter and the snow had a typical New England ice glaze in most places. Especially on side slopes the arrangement was not working well. I would predict any single pole attachment would suffer from the same problems.

One other innovation I've adopted as a result of two Baxter SP trips is a knotted sisal rope that I can run underneath the belly of the sled when needed. It acts like the brake chains on Nat'l Ski Patrol toboggans and helps hold the sled back. I found leaving the skins on my skis and using the brake on the sled was just the ticket for skiing back out from Chimney Pond.