New member intro and ski course anchor ?

[Guest]

Hello Everyone

 

Been lurking for a while now. Just signed up and need to introduce myself. I live in the south central PA area. Our family owns a cabin on the Potomac river in Hagerstown Md area so that is where all the skiing is happening.

 

My 2 oldest kids have gone to Cobles ski school the last 2 summers for a week. My daughter who is 10 is turning out to be pretty good on the slalom ski.

 

I bought a Prostar 197 the end of last summer which is working out well for us as a beginner ski boat.

 

Since my daughter was running the course at cobles. We are working on getting a portable course for our water. After talking to several other skiers in our riverfront community. I discovered that there had been a course on the water in years past And it was only about a 1/4 mile off my dock. Their old course was a full portable with the river anchors and was left in all summer.

 

It was decided that since traffic is greatly increased since the old course was used. We would buy a new course from Ez-slalom that was just the main line with the entry gates and boat guides. The turn balls will be individually anchored

 

We will take the mainline entry gates and boat guides out on a regular basis but let the turn ball in

 

Here’s a question with permanent anchors for each end of the mainline what is an easy way to tension the mainline without having to get in the water each and every time we set it up and remove it.

 

I don’t think dragging the down river anchor with the boat is going to work since the turn balls are individually anchored we need that downriver anchor to stay in the same place so that the course is straight and aligned with the turn balls

 

One thought was to use two downriver anchors one to run the mainline rope through to keep it straight and one smaller one to pull with the boat to tension the line each time we put it in and out

 

 

Water depth is 7-10 feet

Thoughts?

 

Jim

[jpwhit]

I've never had a course in a river, so I can't offer much help with dealing with the current. But I've maintained a couple of courses on a public lake for years. I'm not sure I understand the purpose of individually anchoring the turn balls, but using a traditional mainline for the pre-gates, gates, and boat guides. Even in a lake w/o any current, I think keeping the individually anchored turn balls in alignment with an anchored mainline is going to be a nightmare and time consuming.

[skihacker]

We used to run a mainline with separate buoy anchors, not on a river, but anyway it was a constant pita, the mainline was forever off to one side or the other. I'm not sure how they work but insta slalom lists river adapters on there website.

[ALPJr]

May want to look into Accufloat courses https://www.accufloat.com/courses.html

[Lars]

insta slalom and accu float sell river adapters you can add on that help keep the arm straight in a current.

https://www.accufloat.com/images/sc%20110.html

 

[eyepeeler]

You've got a cabin...on a river...lots of traffic...FREEEEEEEEEE SKI...

[foxriverat]

We tie a cinder block to middle of the pvc between every gate and sink it. If you let it float on public water someone will hit it and brake the pvc. You might have to straighten the gates out every once in a while but they won't move down river. If you try pulling course tight with boat you will bend the gate pvc in half. Been there done that. We use individual heavy cement anchors for turn balls as the pvc arms always bend over time even with the ends anchored with cinder blocks. Yes it's a pain taking care of a course on a river. We cut the buoys out end of season and leave everything in.

[foxriverat]

Also if the river come up a lot after heavy rain. Current moves faster and grabs all the logs from shore and there's a good chance it will screw your course up unless you cut the buoys off.

[lpskier]

The best anchor (in my opinion) is an old cast iron radiator. It will settle into the bottom and never move.

[Zman]

To prevent the mainline from going sideways when you tension it, use two screw anchors with eyelets on top. 30 or 36 inch length should be plenty.

Screw one to the river bottom on the upriver end to be a permanent fixed point for your mainline. Then use what ever weights you choose to tie the downriver end of the mainline to. Nothing tricky about the weight except you want something much denser than water, like steel or concrete. 50 pounds or so.

(Remember, for every gallon of water volume displaced by your weight, your weight loses 8.34 pounds when underwater).

Once you have the mainline tensioned, install the 2nd screw anchor directly under the mainline anchor rope, about 15-20 feet upriver from your anchor weight. Then, pull the mainline anchor rope down and into the eyelet.

Now, if the river drops, and you need to pull a lil tension, you won't change the course path at all. It will remain centered between your turn buoys.

You just need a couple scuba divers and a short piece of pipe to screw the anchors in the river bottom. If the river bottom is deep with soft silt you might need longer screw anchors to get a bite in solid soil. These anchors are not very expensive.

 

You also might want to attach small sub buoys on the 2 screw anchors and the down river weight in case you ever need to find them again.

[Zman]

Also, as @foxriverat noted, be careful if you tension the course with your boat. We built our course with schedule 40 pvc, not the light wall tubing used by portable courses. We do tension with our boat, but never more than idle, and in and out of gear. You only need a couple hundred pounds of tension.

Fortunately, we are in a lake with minimal lake level variation. Seldom need to add tension.

[BraceMaker]

Any shoreline access?

 

Reason I am asking is the concept of fixed turn balls with a non-fixed mainline based boat guide and gate means that if the upstream side is fixed and the downstream side is tensioned, then the tension will in effect pull the gates and boat guides down stream in reference to the fixed turn balls. So if the water level goes down your upstream gates will move towards 1 ball. And if the water level comes up the gate will move upstream from 1 ball.

 

How much will vary by tension and water magnitude.

 

So if I had to execute that concept I would try to get shoreline access, then however many feet beyond the entry and exit gates probably around 50 feet past the gates I would set a heavy anchor and string a subbouy on a cable down through a loop on the anchor and run the cable to shore possibly through a few screw in anchors if you can get to the bottom. Then on shore I would put those onto a winch such as a boat trailer winch.

 

So now you show up, motor to the shore and someone lets out the cable off the two boat winches which lets those subs pop to the surface ~5-10 feet of line. Now you motor over to the upstream bouy clip on the mainline and start going down stream setting the booms and bouys as you go till you hit the downstream bouy and clip to that.

 

Back to shore and you pull tension back onto the system which will pull the course mainline into alignment down the middle of the turn balls.

 

Once you figured out a calibration for the course being centered you'd take some spray paint an spray paint the cable at the winch like a red dot then put orange paint on the cable a few feet each direction. That way if the water comes up you'd let out a bit of cable from the red dot on both winches and be roughly centered, and water comes down you pull in a bit of cable from the red dot keeping equal on both winches.

 

[BraceMaker]

A somewhat cheaper/lower tech version would be to use logger chain on both ends to a fairly heavy anchor. The chain is going to act like it does on a ship and try to lay down on the bottom. So you'd figure out how much chain on both ends and where on the chain to hook the main cable. Add a logger hook to the mainline, use a magnet to retrieve the chain and then find and connect the logger hook onto the chain.

 

Repeat as before retrieve the far and chain, hook on and drop it then once the chain has pulled tension on the course you might have to snag one or the other end and pull a few more links of chain up and hook it.

 

This works on the same principles like a ship so depending if the river is maybe 15 feet deep you'd run 30 feet of chain on both ends from the anchor so the chain has enough mass to pull tension on the mainline when dropped.

[Zman]

@BraceMaker interesting idea. But, can you get two 30 feet lengths of heavy ship anchor chain for less than $25 to $30 for 2 screw anchors? Maybe at a scrap yard?

[BraceMaker]

@Zman harbor freight would be my go probably. Wouldn't need to be crazy heavy think that a typical portable uses one anchor per end something like 20lb river anchor. So the amount of actual tension only needs to be whatever amount of tension those anchors hold before slipping. So instead we have fixed anchors on both ends, we don't have 6 turn bouys and we don't therefore have 6 long arms to pull straight I would imagine that the course would straighten up under maybe 30lbs of total tension.

 

So if the chain wasn't heavy enough you could always hang some weight on the chain to increase the amount of tension, or as you pull more links of chain in and hook it the total amount of chain being picked off the bottom goes up.

 

This doesn't need to be super heavy chain to accomplish the job.

 

[h2onhk]

@JimK I also live and ski on a river with my family. Depth is similar (7-15') and we have always used a portable course. Once the spring and early summer flooding pass, we put the course in on Sunday evenings and pull it out on Thursdays evenings. This helps mitigate the risk of damage during the amateur hour shenanigans that take place on the weekends. To expedite the process of installing and removing, we bought an old 20' junk pontoon boat for $600 and stripped it down to just the deck. The portable course is stored on there underneath a tarp when not in use. A little 9.9hp outboard motor is used to maneuver the pontoon around. With the large flat work space, 3 of us have plenty of room to work and stage the PVC arms. We can have the course in or out in about 20min, probably 15min if we really pushed it. It also keeps all the water, scum, muck and other fun stuff that the PVC poles bring up from the bottom, out of our ski boats.

 

We have one permanent concrete anchor staged upriver of our course location with a 100' section of cable and old buoy attached to it. When putting the course in, we just connect the portable course mainline to the cable and do our thing. This ensures we always are back in the same spot where there is protection from the wind and light weekday boat traffic . The 9.9hp is more than enough to tension the downstream anchor and properly align the course.

 

Pending on the amount of rain, the current can have an impact on the position of the turn balls a little bit. We just simply adjust our gate timing (early/late) to compensate for how much the balls have drifted downstream. I know its not ideal, but for a public river its the best we can do.

 

I know this doesn't answer your original question about the mainline anchoring relative to the turn buoys. Just trying to offer another solution from one river skier to another.

 

Awesome to hear your kids are into it as well. Definitely makes it more fun and provides another set of hands when needed! My 13yr old has been consistent on the mini course this year at 27mph (finally got her interested!) and my 8yr old son ran the mini course on a trick ski for the first time last evening. Grinning ear to ear as he rounded 6 and came through the gates. Good times!

[wski1831]

Never seen it or used it but Wally Skier has a sinkable course that might work. Or possibly an adaption of the sinking mechanism adapted to an anchored course. Regardless of what you put in I would definitely have subfloats on everything. Good luck!

[BKistler]

I’m originally from PA and skied a tournament on the Potomac just above Williamsport in 1967. Nice spot as I remember.

[JimK]

Thanks for all the reply’s. I might be able to get shore access on the up river end of the course. The chain idea is intriguing as well.

 

 

[GaryJanzig]

Check out insta-slalom.com It has river adapters.

 

[skierjp]

@JimK Been working with ski courses for over 40 years and 15 of them up north near Pittsburgh on the river. A EZ Slalom won’t work in any current. I would recommend Accufloat by Mike Suyderhound. I’m curious what the bottom of the river is? In that shallow depth I would have a scuba diver screw in 42 inch anchors with a 4 or 6 in blade. You can get these from Tractor Supply. They will only last maybe 2 years before they rust and break. The best way is to buy the stainless steel anchors from Milspec Anchors in Alabama. You can also get a stainless boat trailer which from Amazon. When you order the course from Suyderhound also order the anchor line (stainless cable) from him that is the same as the ski courses. In that depth I would have the anchor lines at least 180’ good reference for where the 55s go. My tip would be as long as it’s not going to flood leave the main line in and just remove the buoys.