Pulk stabilization.

[MadRiver]

I’m having problems with keeping my pulk stable and I was wondering if you have any additional suggestion?

Some issues:

It tends to turn over to the left if the trail is not well broken out.

On groomed trails it tends to also pull to the left.

I’ve noticed that the weight has to be as low as possible in the sled.

I cross the poles for added stability, which only works sometimes.

I’m thinking of adding stabilizing fins to the bottom.

Should I uncross the poles and add a cross piece to keep the poles locked in position?

Any addition suggestions would be helpful.
Thanks,

 

[MichaelJ]

I found much greater success with crossed poles in an "X" formation than with straight poles with a crossbar forming a rectangle. The latter was way too hard to turn.

What do you use at the center of the "X" ? It should be flexible. I use a loop of velcro that's tight enough to keep the "X" in shape but has enough give for it to deform when turning.

 

[DSettahr]

Yeah, try using something at the center of the "x" that will keep the poles from separating...

 

[MadRiver]

I might have wrapped the bungee cord too tight to keep the poles crossed, but not loose enough to allow movement.

 

[bcskier]

What style sled are you using?

I've tried a few different manufacturers sleds for use as a pulk and found that most were unstable unless weight was packed very low. The type I use right now is a black Torpedo toboggan style and has been the best. It is 13-14" wide and about 5' long. The original type I used was a red Coleco about the same width but a 1 1/2- 2 feet shorter. Both of these sleds have sides that are vertical. The sleds I had the most trouble with all had sloping sides such that the bottom was narrower than the upper rim. On a recent trip in to Katahdin I can say that the Paris Expedition sled is by far the most popular and has that vertical side configuration I mentioned.

As far as crossed or uncrossed poles go I have a rigid section across the front of the sled with elbow connections on either end (pvc conduit material) and have never used crossed poles. My impression of the need for crossed poles has been that it provides a bit more control than straight poles in the absence of a rigid horizontal piece across the front. I do have stabilizer fins on my sled and found that they make a huge difference running downhill on narrow trails (such as Avalanche Pass and the trail out and back from ADK loj to Marcy Dam). Before fins I would have the sled slewing from side to side causing collisions with tree trunks along the trail.

I could provide more details if you wish.

Phil

 

[snoshoovt]

Pulk help

I have a Paris Expedition sled and several years ago, after watching my hiking buddies lose their sleds off the side of the trail at Baxter, I got a couple of pieces of aluminum from Aubuchons, something like 1/8" x 1/2" x 4', carefully bent them to match the countours of the outer ribs in the sled, drilled and countersunk holes for flathead bolts every 6",with washers and nuts on the inside of the bottom, all stainless of course, and laid on the inside a thin piece of foam sleeping mat to cover the bolt heads. The result was a much more stable pull on the trails, and the bonus it it makes a great carving sled for going down ski slopes. A bit of work but it really solved the issue of the lack of directional stability from the rounded plastic bottom ridges.
Also, agree with the crossed poles, in my case pvc electrical conduit with a poly rope inside and caribiners at each end.
Lots of pulk solutions, this is just one...
Enjoy,
John

 

[MadRiver]

Thanks for all the information.

Here are some photos of my current configuration as far as my poles. I have since added metal loops along the sides to attach bungee cords. And two reinforced metal loops in the front and back to help pull if needed.

http://www.facebook.com/album.php?id=1450265390&aid=96860

http://www.facebook.com/home.php?re...&set=a.1135110950102.20569.1597196006&theater

If it is not too much trouble could you post or send me a PM of some photos of your fin configuration. This is my first attempt at a pulk and I’m leaning a lot of what I need to do to my next model.

Thanks,

 

[MadRiver]

Bought a 72 x 1½ x 1/8 piece of angle iron make of aluminum and cut it in half. I will bolt it to the bottom of the pulk to act as a runner. Hopefully this will help with the stability issue.

 

[MichaelJ]

Make sure it stays smooth and straight; navigating the Zealand Trail bypass area, for example, with all its rocks, could do a number on such a runner.

 

[DougPaul]

Bought a 72 x 1½ x 1/8 piece of angle iron make of aluminum and cut it in half. I will bolt it to the bottom of the pulk to act as a runner. Hopefully this will help with the stability issue.

Sounds like it might be overkill--remember you also want the pulk to be able to turn too...

You might take a look at Ed B (Pulky Ed)'s pages on building pulks: http://www.skipulk.com. He gives rather complete instructions on how to make pulks, including adding fins for stabilization: http://www.skipulk.com/images/pulkbook.pdf

(Ed has an account--I wouldn't be surprised if he chimes in at some point...)

BTW, the advantage of crossed poles is that as you rotate your hips going into a turn, the pulk will act like a rudder turning in the same direction and it will tend to correct side-to-side drift. Uncrossed poles will turn the rudder in the wrong way and will not tend to correct side-to-side drift. These effects may become more important if tracking--stabilization fins are added to the pulk.

Doug

 

[MadRiver]

You might take a look at Ed B (Pulky Ed)'s pages on building pulks: http://www.skipulk.com. He gives rather complete instructions on how to make pulks, including adding fins for stabilization: http://www.skipulk.com/images/pulkbook.pdf

You might be right on the overkill. I've looked at Ed's page a lot in the beginning stage of building my pulk and copied his design as best I could. I might cut the runners in half and mount them towards the back end like Ed's photo shows. Bcskier also sent me a photo that suggests that I might want to reduce the size of the runners.

 

[MadRiver]

I cut the fins down to 12 inches and mounted them on the back of the pulk. As I pulling it up my driveway, which is mostly ice, I could feel the added friction. Once I entered the woods, the pulk glided along a lot easier. The unbroken snow was heavy and wet so the pulk didn’t pull as level as I had hoped and heeled over slightly, yet it never tipped on its side as it did in the past. I pulled it around a number of trees with no problem, so I do believe the fins actual improved the stability. I will test it further before I have to haul supplies to Lonesome Lake in a few weeks.

 

[Ed B]

Make fins removeable (wing nuts or thumb nuts)

Lots of great advice already-
* Biggest issue is to have a sled big enough to keep the weight low -
* Crossing the poles helps deter rollover in one direction but needs a rubber o ring or velcro to discourage it from turning over in the other direction.
* Fins add to tracking and are essential on the downhills but they can really add friction on a long uphill slog on a packed trail. Make them removeable with wing nuts or thumb bolts.

The thing I wanted to add that wasn't covered yet is that the tightness of your connection to the sled and to your hip are just as important as all the above. If you have a lot of slop in either of those connections you will see a dramatic loss of control and more frequent roll overs. I tried to look at your photos but could not see them. Enjoy your trip - I miss the White Mtns- I have been in MN too long.