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Homemade Rope Tow @ Ullr's Gulch; Details on a rope tow for downhill skiing that I built for cheap.
Topic Started: Aug 17 2012, 06:20 PM (2,942 Views)
undy
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I've skied here in southern Wisconsin since I was a kid in the '60s and my folks were friends with the owners of the local ski hill, Tyrol Basin. It's a great little ski area (for southern Wis.), and they make excellent man-made snow. I still buy a season pass. (Don't get me wrong, I still long for skiing Pali at Arapahoe Basin again, but I'm a bit too old and a lot too beat up for that nowadays.)

But powder is my holy grail, and on those rare occasions we actually get any powder snow, it all gets skied up in just minutes after they open the hill. To make matters worse, they don't stay open all night for skiing with my friends on full-moon nights with bonfires burning. So you might understand the reasons why I've dreamed about building a rope-tow on a north-facing hill on our farm since I bought the property.

There were also several valid reasons why it did not get built: 1) Tyrol Basin is only 15 min. drive, and I have a season pass, 2) Southern Wisconsin is known for marginal (read: crappy) natural snow and without snowmaking you're dependent on mother nature, and 3 A rope-tow is expensive to buy/build and without knowing whether the skiing would be "fun enough" I didn't dare make such an investment.

What I needed was to build a "proof of concept" machine, so I could try it out for a couple years before I splurged. The question was: HOW? Then two summers ago I was at the local surplus yard and came across about 1000' of 1/2" 3-strand nylon rope for about $65, so I decided it was now or never for the rope tow. The rest had to be virtually free. But that didn't mean it would be simple or quick, in fact there were a lot of details to work out. It would just take some time.

I laid out the course of the tow up the hill, generally diagonal up the hill to give access to the steepest areas while still allowing you to choose easier, longer routes too. I decided to use old telephone poles as towers, and the 8" wheels and axles off small junk trailers as pulleys. The tow would be powered by an 8hp garden tractor located at the bottom to allow me to ski down to it in the event it quit running. I would build a tensioning device at the top, to maintain sufficient tension on the rope for it to be gripped by the drive wheel/s. For a safety circuit, I would use a "normally-closed" relay in the engine kill circuit. (By running a current through a loop of wire run to the top of the hill to power this relay in an "open" state, the engine could run while the loop was intact. Opening the loop at any safety switch location "closes" the kill circuit relay and turns the engine off.) 1/2" rope is too small to grab onto effectively, especially up some of the steeper areas of the planned route, so some sort of "grippers" had to be found.

Then, assuming it all worked and we had some snow and the skiing was good, it might be time to actually invest in a true Rope-Tow. Over the course of that fall, I constructed the device. All told, the cost was around $120. Come winter, we deployed it on the hill, and it actually ran out pretty good. It pulled one skier approximately 440' in 55 seconds, hands free. Suffice it to say that I intend to operate it again this winter. But of course, once you have a rope-tow you suddenly realize a need for a groomer, and it's all downhill :blink: after that. That's how I ended up on this forum.

I started this thread in response to a request. It's the story of the rope-tow. I know it's not cross-country skiing, but as long as anybody's interested, I'll write about the details we worked out and how it's been upgraded and where I expect it to go in the future. I'm at the mercy of my kid as far as photos go, but if possible I'll add them too.
Edited by undy, Mar 4 2013, 02:13 PM.
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
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couchsachraga
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Sounds interesting.. please do post more (especially what worked and what didn't...) and images when you have time. I hadn't thought of the setup for the "emergency kill switch" but it sounds like a really good one - did you have one switch (at the top) or multiple places you could break the connection?
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undy
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Couchsachraga,

I plan to write about individual parts of it from time to time, and include a lot of the R&D progress. You mentioned the emergency kill switch circuit, so I'll give more details of it now.

I've only installed two kill switches so far, one at the top and one at the bottom. But I plan to add them to each tower so anyone can kill the lift at any time. The biggest safety drawback so far is that we never have an actual operator - it's just start 'er up and everyone start skiing. To date, everyone skiing was easily an expert skier, so that lessens the danger a bit. (We have a rule that if you fall down, then your skiing privileges are revoked, and if you're hurt, then you're trespassing. :D ) But I figure the more kill switches the better.

The kill circuit incorporates the "normally closed" relay as I described in the first post. So I used a two-conductor wire to run up the hill. I can add kill switches anywhere along that line by merely adding a SPST on/off switch in one conductor. Opening that circuit anywhere will close the relay and kill the engine.

The top switch consists of a female extension cord end attached to a short post about 30' before the top pulleys. A male extension cord plug with a short loop of wire connecting the terminals completes the "switch". The male wire loop is tied to a PVC ring which rides on the rope. If you go too far, you hit the PVC ring which pulls the male plug from the female wire end and you've opened the circuit and killed the engine. To test it, I held on and rode through and I easily stopped before the pulleys.

It occurred to me that if someone tripped the top safety switch by accident and didn't realize it, they might ski back down to the bottom without resetting it. Then the engine would be off until someone went back up to the top and reset it. To allow me a way to ride the lift back up and avoid a long walk, I installed a safety circuit bypass switch to allow me to run the lift without the safety circuit active. I ride up and reset things and ski back down. Then I flip the bypass switch back to 'off' and the safety circuit is once again activated.

Warning Disclaimer
Remember that this rope tow was intended to tow me, my son, and a few select friends who are very capable. As I reread what I've written, it sounds pretty unsafe to ride it and ski unsupervised, and the safety circuit bypass and all. I'm not recommending that anyone else do what I've done or insinuating that it's a safe device to use. It certainly has the potential to hurt or kill someone, but so does my Subaru. I'm merely suggesting a way that someone might build a rope tow, if they were going to do so. You do it at your own risk. And no, I'm not an attorney.
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
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undy
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Rope, Pulleys & Grippers

As I mentioned, the initial goal was a "proof of concept" arrangement, so everything had to be done for little or no money.

Because even the price of a new rope was a sizable investment, this was perhaps the biggest commitment to make in building the rope tow. If the skiing wasn't satisfactory, it would be a big waste. Luckily, there's a surplus yard nearby. One day I noticed a bunch of 1/2" yellow nylon rope on spools - 300' for $25. There was also a big box of the stuff all jumbled together with no price. When asked, they gave me a price of $30 for the box. I bought the box and one spool. It turned out to be over 1000' all together, but in 5 pieces. I followed these directions to splice the rope. After 2 years, the rope is still fully functional.

I figured I needed at least 2 midway towers to elevate the return rope, and 1 for the top. I used old telephone poles about 16' long, with 4-5' buried. A neighbor had 2 old snowmobile trailers which had rusted into junk. I cut the axles off and in half, which left me with 4 wheels with bearings on a half axle. To mount them on the poles, I made a jig to run a 2x6x24 sideways across my table saw which left a concave cutout that mated to the tele. pole. Two sections of threaded rod, washers and nuts holds everything together. The midway towers have one pulley each for the return rope. The top tower has two pulleys, one on each side. To provide rope tension, the rope runs over these pulleys and down to an old car wheel and front wheel bearing mounted to a couple L-shaped (like a forklift) arms which can be loaded with weight. (The car bearing had been replaced due to being noisy, but it works fine for the low speeds of a tow. It and the wheel were free.) The wheel/L-arm assembly simply hangs on the rope. I'm running about 250# of weight, and probably need to have more to carry more riders, but with the small diameter rope, I don't know how much I dare add.

Now, you've probably been thinking that 1/2" rope is too small to use successfully for a rope tow, and I agree. But the problem is mainly with some way to attach yourself to the rope comfortably. (Moving the rope is the other concern, and a larger diameter rope would definitely grip the drive pulley/s better.)

I looked up various rope grippers like Mt. Hood's or Various but eventually designed my own. I cut 6" of 1" dia. tube as a handle. On one end I welded a curl made of 5/16" rod, made by wrapping it around a 1/2" rod. The opening in the curl allows the you to slip it over the rope, but when you twist the handle perpendicular to the rope it crimps the rope within the curl thus gripping the rope. You still need to grab the rope by hand to start yourself moving, but after that it's pretty easy to attach the gripper to the rope.

It's possible to ride just by hanging on to the gripper handle, but even that's more effort than I fancied - I wanted to ride hands-free. On the other end of the handle, I added a small loop of 1/4" rod. I then got a few seatbelts from some junked Subarus and made up some belts which fit outside of one's jacket. In an emergency, they can be quick-released with one hand, by pushing the seatbelt button. In the front, I sewed about a 4" flap which ends in a metal hook I made out of 1/4" rod. Once you've grabbed the rope and started moving, latch the gripper handle onto the rope, and attach the belt hook onto the handle, you can ride with no hands. It takes some coordination at liftoff, but it's pretty easy.

Once again I'd like to point out that this tow probably has plenty of potential for injuries or death. I'm not suggesting that anyone build one, or ride one. But if you're inclined to doing dangerous things and wanted to build yourself one, this is a representation of one way it could be done. But I will admit that it is a lot of fun.
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
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thycol2
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what is the normal size rope on a roap tow ?
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undy
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1" or a bit bigger, usually. That's comfortable enough to grab onto and hang on for a while. It also has less stretch than a smaller diameter rope, which makes it easier to get the proper tension on the rope.

It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
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nelsoncat
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Wow, this is exactly what I wanted to do after skiing at Devils Head as a kid in the early 70,s.
I also said one day I wanted a Tucker. I finally fulfilled that dream last month.
How did the rope tow fair the winter?
Craig
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undy
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Hi Craig,

Devil's Head. There's a blast from the past. When I skied there in the 70's, I didn't realize how flat that place is. I was there once within the past ten years, and was shocked.

Well, the rope tow had it's ups and downs (pun fully intended). I had some issues with the starter solenoid freezing, so I had to jump it to start it up. I also seemed to have killed the battery, but that may have been from it being left on inadvertently. I plan on pulling the tow into the shop soon and get things working better for next year. The rope's on it's 4th year now, but still seems like it'll last another year at least.

But I got in four days of private powder skiing at Ullr's Gulch, long after any fresh snow was gone from Devils Head and Tyrol Basin. I ski out Tyrol, and then I go home to ski. (Oink, oink!) I'd have shared, but my son was out with an injury for most of the season and my buddy Kevin was in Winter Park for the winter. But that's in addition to nearly 70 days at Tyrol and a weekend at Bohemia. Tyrol was open for four months! So I had a pretty good season for the midwest.

If you're ever down towards Madison and would like to stop and look at it, just let me know. I intend to keep it going, at least until I'm too old.

Cheers,
Paul
It is better to go skiing and think of God, than go to church and think of sport. Fridjof Nansen
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