Anchoring your slalom course

[Skoot1123]

So with our lake project approved, we are looking at our options for anchoring our slalom course to the bottom of the lake. In looking online I found American Earth Anchors, they have some stakes which screw into the ground that have threaded ends on them. I might add that we want to use a pulley system to raise and lower the buoys on the course so those that find them distracting can make them disappear as needed. That is our intent at least.

 

Have others used a pulley system to pull more than one buoy or even the whole course down? What lessons learned can you share? Thanks for the help!!

[BraceMaker]

Are you doing individual anchors per ball? Or a portable course in the lake?

 

Not sure you'll find a good way to "pull" the balls down - lots of cable to run individual lines to every bouy, through an anchor and to shore.... Which is why sinkers have sufficient weight to sink the ball and use a 2nd bladder to make up the buoyancy to surface the course.

[A_B]

Skoot, our lake bottom is solid clay and hard that we bent a large screw in anchor that me and my friend were wrenching on with a 3 foot pipe stuck through the eye ( in 18' of water - dumb 25 year old move). We then got a large boat anchor and got that to dig down into the clay and that served as our fixed point. The other end goes up to a winch and we adjust with water level.

 

I can tell you that I would be afraid to pull all the buoys down with the winch. The strain on the connections would be pretty high. I am the chief course tightener and when I just get the pregates to sink a little, I know the course is tight, but there is a lot of strain on the cable at that point, if I let go of the winch handle it would zip around and bust a knuckle.

 

Maybe someone is doing it but it might be easier to take half the buoys off or something like the weighting system I have seen on the web. EZ Ed might have a system to sink in place.

 

This system sounds like a lot of work:

http://aquaskier.com/articles/submersible_waterski_course_project.htm

 

 

[A_B]

@OB, we have talked about it, but our depth is an issue, unless we do it in the winter through the ice.

Not against it, but would need to get some help doing it. We don't have a lot of manpower available.

 

I have been thinking about angling the course a little north and south to help out the evening sun issue.

[MattP]

@ab it's worth it to get an anchored course surveyed. How deep is the lake?

[A_B]

18 in most of the course. I can't hold my breath like I use to. @OB's rope entanglement story scares the crap out of me.

[MattP]

@ab scuba gear is your friend. His story scares you ? I was about 3 feet away and had no idea what was going on. If he was under much longer I would have gone in for him.

[A_B]

My lake partner is not very motivated. He skis very little and not really looking to do tournaments any more. I at least am hoping to get back into it.

The other owner hasn't been on a ski in 20 years. More of an investment for him. We for sure would need a diver to pound in anchors on the weights.

[RichardDoane]

the Broho course is still a floater with a stainless mainline, well anchored at each end, it adjusts with the changes in water level which is very handy, but for next season's BigDawg, we'll be making a set of anchors and setting/surveying a RC course. I make the anchors from worn out tires filled with cement with an eye bolt from Skier 2 Skier, easy to handle/adjust, and heavy enough to stay put

[Ed_Obermeier]

I still can't understand why sites that skiers have skied on for years or even decades use a portable course. Drop anchors and survey!

 

Here's one reason - maybe not a portable course per se, but a floating permanent course is easier, faster, and possibly less expensive to install/remove for the vast majority and accuracy (at least from us) is not going to be an issue. Skier's turn balls at the ends of PVC buoy arms can potentially be less than perfect but even that issue is easily addressable with minimal efforts required. But agreed @OB, if I had my own permanent site I'd try my damnedest to install an individually anchored-in course if possible. For some sites (deep water being one issue) individual anchors just isn't a realistically workable option for the vast majority.

 

I've discussed with several different skiers over the years the possibility of a pulley system like @skoot1123 envisions, if fact I think we've discussed it ourselves in memory serves (which it doesn't as well as it used to...). You might potentially make it work with a 4-cable type course system (each line of buoys running the length of the course - 1-3-5 on one side, each of the two sides of the boat lane, 2-4-6 on the other side, each on a separate cable per line) but it's gonna be a huge PITA to install and more so to maintain. Pulling down the entire course as a complete system - ain't gonna happen. The necessary infrastructure and the geometry would be a total freaking nightmare, wouldn't even consider it. Would be bad enough with the 4-cable system, much less an entire course. @AB is completely correct, the stress on the connections and cable would be way too much and that's only one of several issues.

 

Ultimately there are 4 realistic possibilities IMO. 1) a sinkable system such as a Wally Sinker (cost the primary issue with this option), 2) remove the buoys and let the structure (for a floater) sink to the bottom, then fish up and reattach the buoys (time and PITA factor primary issues with this option), 3) individually anchor each buoy with a sub buoy system, remove and reattach buoys as required (again time and PITA factor the primary issues), 4) install/remove a portable course as required (install/removal time the main issue here). If I've missed an option feel free to add to this list.

 

Ed

[A_B]

Richard, what kind of line will you use from anchor to sub buoy? If we ever do this, I want a line that will last a long as me.

 

I have thought of dropping in the boat guides in pairs with a fixed metal bar or something to get proper widths, but I have mixed feelings on doing it that way.

[9400]

Cross-line course is also an option, especially if the width is 200' to 250'. I've also been involved with one on a lake 400'ish wide. Cross-line is extremely accurate if done properly and width isn't an issue. The issue is width and shorelines.

 

If I were to do individual anchors, I would prefer to do it in shallow water before the lake fills up if possible.

 

Another option is to layout boat guides and turns on a 2" schedule 40 pvc, then you only need 2 anchors per set instead of 3. (this way would also be easier if you could install before the lake fills up).

 

I have not installed one that needed to be sunk, so I've got nothing for you there. But Dr Jim Michaels can help you if you need one that needs to be narrowed for setting records and grabbing glory.

[ctsmith]

Cost wise, anchors are less than a portable, but a WHOLE lot more work. I've currently got a rope course on the lake I ski and will use it as a template for an anchored course. I've measured the depth at every buoy and have buoy lines cut to appropriate length and ready to roll (using the fingertrap method with sub buoy). The depth at most buoys is 18' - 20'. Anchors are ready. Albritton and Mattox are in charge of setting anchors (much appreciated!). Waiting on everyone's schedule to line up, may not happen before the cold sets in. Otherwise, we'll get it this coming spring.

 

The anchors are a little intimidating. 200+ lbs of dead weight is no joke.

 

[ctsmith]

George, Keith was telling me about your hang up story the other day. Scary. Which sorta leads to another question.

 

What are the merits of building a float out of drums with a winch lift for positioning the buoys, as opposed to moving them around by hand on the bottom?

[9400]

@ctsmith That's what one guy I know did in 25' deep water with no divers. Your question just reminded me of that.

[Edbrazil]

I probably have quite a few things to add. But, I'd like to find out more about this project. Originally, I thought they were talking about getting permission for a course on public water, but on closer reading, maybe they are developing a lake. Even digging one from scratch?

 

To the very first question, here's what I've used a lot of the time for a buoy anchor. This is a so-called "cored chimney block" with approximate outside dimensions 16 x 16 x 8. Interior is mostly filled with concrete and a stainless eyebolt added. Keeping the concrete a little below the top so the eyebolt doesn't stick up and they are stackable. Weight is about 108 lbs. The flutes in the block are good for mud to mush up into or to use to pin through with rebar or similar. May not be EZ to find in other parts of the US. But, can also use regular chimney or "pileaster" blocks w/concrete. They end up around 130 lbs.

[skierjp]

18 feet is a piece of cake free diving. Use a block and tackle off the front bow eye to move the buoys into position. Have the anchors just off shore in about 2 feet of water and bring the bow of the boat in to get the anchors. My wife and I did ours in a couple hours by ourselves. The anchors weighed 175lbs.

[Skoot1123]

Thanks for the input guys - I need to provide some more background info it seems. Don't have time right now, but the basics are this: Course would be surveyed and laid in before water fills the lake. Each buoy point would be individually anchored - pullout strength on the anchors ranges from 600 - 2500 lbf (depending on how densley the clay is packed). With the threaded end we would attach an eyelet and run our mainline through there. Our mainline is a poly covered stainless steel - main pull point (where it would pull on the course to bring it in) is between buoys 2 and 3. Essentially we will crimp the lines from each buoy to the mainline so all buoys would work in "unison" when drawn down. The winch will be positioned on our dock with two pulleys to maintain tension and relieve some of the stress off the mainline. If I get time I'll scan in a diagram showing the crimp sections and pulling strategy.

[jwroblew]

@skoot1123, I have seen courses with each row of balls, gates and turn ball on their own line so you have to winch down 10 rows counting gates and 55s. interested to see your setup.

[MISkier]

Question on the cement anchors: what is the likelihood that a speeding boat can wrap a line into a sterndrive, etc. and fling that anchor into the air (even at 175 - 200 pounds)? Or, do you use very lightweight poly rope to break quickly? I want the course to be safe and also prevent any liability I might have for installing it.

 

I kind of like the anchors at American Earth Anchors that @Skoot1123 mentioned. The "Penetrator" series looks like it would work great and 1000 pounds or so of holding force may help with snagging, etc. I want to move from a portable to anchored course at my vacation site. Since it is a public lake, I want to be careful with any movable anchors that could be dislodged or launched. The water is 6' to 8' deep and the lake bottom is hard packed sand and possibly clay. The anchors listed are much more suited to augering into hard ground than the mobile home anchors, etc. I'd like to install those screw anchors through the ice, but don't know a really good method to wrench them in at that depth and retain the sub-buoy attachment to it. Any ideas?

 

I've though about the retractable course a lot. That many pulleys would be too difficult to keep operational (rope jam and many other things affecting moving parts). If I were going to do anything, I would use a stainless steel ring (about 2") as the cable redirection/retraction guide.

 

For some private sites, I have seen the owners put the mobile home anchors (basically a single-bladed auger) into the lake bottom during excavation. I would use those "Penetrator" anchors if I were doing it and especially if the lake was dry or very shallow with some ability for manual leverage during installation.

[Skoot1123]

@miskier - that is the plan. I'll get a diagram scanned at some point and post it.

[klindy]

Ive used the helix anchors before and they work fine. Use a 4' length (about a 6" disk) for the slalom course and the 8' length (approx 12" disk) to anchor the jump.

 

We surveyed and staked the lake when dry. Use two offset stakes to mark the location (3' next to the buoy location at 90 angle) then we used a auger on a small Bob cat to "pre-core" the hole. Install the anchor in the hole with about 4-6" exposed and backfill. You can set the anchors precisely where they belong this way.

 

Resurvey before filling to make sure everything is where it belongs. Minor adjustments can be made by bending te anchor slightly or digging down and repositioning the anchor as needed.

 

Be sure to use galvanized anchors and not the painted option. Note these are NOT mobile home anchors but the kind used to guy telephone poles, etc.

 

I'd have concerns about rigging some kind of pulley system to lower the course. Besides the complexity pulling sideways on any anchor is bound to move it over time and repeated tension. Putting a sub buoy 3-4' down and a clip attachment on the sub and you can pull all the buoys in minutes.

[mwetskier]

what ever you put in dry you want to make sure its rust proof cuz we have a friend in texas who used big re bar with holes drilled for buoy lines and now the end of the re bar rusted off and they have a under water problem to solve.

[Jordan]

I would look into helical piles...they are strong galvanized steel, basically giant screws. They could easily be installed before the lake was filled or from on top of the ice.

 

Check out this video on youtube about them...

 

http://www.youtube.com/watch?v=bAax299agAk

[skiray]

@skoot123 - sounds like you have lots of options since the lake will be dry when you survey in. I guess our approach seems weak compared to the ones above, but we took a 12X16X8 in block and filled it with concrete. It has a SS eybolt with a washer sandwiched between two nuts in the concrete. We took a shovel and dug a hole at each block location and buried them flush with the lake bottom. (prior to any water being in the lake) The course has been straight as an arrow for 3 years. The guy who owns the lake, unfortunately, pulls kids on a tube an routinely knocks off bouys. A rookie boat driver has hung the boat on the bouy before and broken the tubing. We haven't had a single anchor move.

[A_B]

My friend who had his lake dug a few years ago, so probably 5-6 years ago, used screw in augers while the lake was dug, and after the water came up, they kept pulling out, so he went to a cable course. For sure use any of the methods above vs the augers.

[A_B]

I have thought of laying chain link fencing, or some type of galvanized or stainless chicken wire or garden fence with links in it, on top of the anchors, so instead of pushing and lifting weights, you could use a snap hook or something like it, to hook on to the fencing for fine tuning. Not sure it would work, but sounds pretty easy to move the buoy anchor point.

[boarditup]

I had the anchors used for holding utility poles upright spun in by a utility contractor. I had a surveyor mark the locations both before and after. The anchors I used have a threaded top for the rope attachment. I had a couple that were off by less than 4" due to the auger walking a bit when they first started to spin them in. I had an angle-aluuminum adapter punched out to allow for a bit adjustment on those. It worked well and I've had a few R tournaments since and have never had an adjustment issue.

[klindy]

we used the same "screw-in" augers as described by @boarditup. The difference is we cored a hole for the anchor and back filled which put all of them in the exact location. There's no way they are going to pull out as noted by @AB. Lake bottom is sand with a layer of clay - no muck.

 

@AB were they the short "mobile home" anchors or something bigger?

[Skoot1123]

@ab - good point. I looked at some screw type augers that have only 1.5 - 2 turns on the Auger portion of it. In my opinion - not enough holding power. Is that the type your friend first used?

 

The American Earth Anchor goes down 14 or 18 inches (depending on the model you get) and is fully spiraled until the head of the anchor point.

[Jordan]

The helical piles are supposed to be screwed down until it takes a prescribed amount of force to turn indicating it into much harder material than the silt/clay on the top layers. This is often 20 to 80 feet deep...they would never pull out installed in this fashion.

[ctsmith]

George, appreciate the detail. Sounds like a plan.

[MISkier]

@mwetskier, to reattach lines to the rebar, would it be possible to use a stainless steel hose clamp to secure a line to the rebar? You might want to have the inside of the clamp rubber-lined to facilitate compression and a good seal over the textured surface of the rebar. Just place the clamp over the line and rebar and crank the two together, maybe with some sort of knotted end on the line to prevent pulling through. It's not the same as a hole through the rebar, but should be easy to do. Yes, a good tug on the lines when snagged could remove the clamp. But you can put it back or do multiple clamps along the length of the rebar for redundancy and extra holding power. And, if you set your buoys up with a sort of a fuse, that can reduce the impact of a snag.

[A_B]

The augers he used were only a couple feet long at most. I saw a few attached to stray buoys.

 

We used 3 to 4 footers and then ran into concrete clay hard pack and couldn't get in as deep as we thought were needed.

[klindy]

@Skoot1123 The "penetrators" from American Earth Anchor might work. But the taper of the anchor and the relatively small flighting will make pull out easier than the helix augers.

 

Imagine a fence post driven into the ground. Pulling it straight up out of hard ground will be difficult. Add water and wiggle it back and forth for a few years and it will likely give up pretty easy.

 

Also, the treaded tops will be good for the initial installation but I highly doubt you'll thread anything on (or in) to it in a few years. The aluminum material may make it easier but depending on the chemistry of the water you may have trouble. I'd look at the "guying top" as a better long term solution.

 

 

[Edbrazil]

I have done courses on dry or mostly dry bottom, but rarely have that luxury. Worked with Bob Avery in Tennessee back several years. Used something like a "Bobcat" backhoe to dig a little pit after first marking locations with dowels & flagging. Then rolled anchors into each pit and packed them in while measuring with the Total Station. Should be able to get everything to well within one an inch, and more like 1cm. In this case, the anchors were 5 gallon cans of concrete with stainless steel eyebolts. Last year, the full re-set at Pangaea in NY state was mostly a bottom job using concrete-filled tires.

 

It would be a serious and costly project to make a bottom-anchored course that could be remotely lowered. The infamous year 2005 incident at Dousman, Wisconsin always comes to mind, and that was just to remotely narrow the 6 skier buoys.

 

I think that the WallySinker design could be modified, and work in depths of 8+ feet, but not easily or cheaply. Back-back when, "Accufloat" had an optional feature where pull-down lines laid across the PVC arms. Was not EZ to make it work right, and is no longer an option. See notes above by others about pulling down courses or individual buoys.

 

I've done courses that are individually counter-weighted that work for somewhat varying water level and removal/re-setting. Might be an option for say, one side off the skier buoys, so they can be out of the way while important functions like tubing are going on. See sketchy diagram attached. At a site with relatively clear water, you just need a boathook to pull up a loop to clip a buoy rig to.

 

Also attached: a picture of an "Anchor Wanker" which is a great tool for working in depths that are not EZ to free-dive, such as 20+ feet. Floatation modules, winch crank, and mount for a survey prism. Shown sitting on a PWC trailer. A waterworker who is a good Wanker can typically get things to about 3-4 inches on the bottom for starters. Then, should only be one dive needed on some anchors for a final adjust.

 

[MISkier]

For those that have mentioned the helix anchors, those look great. For my installation, through the ice into a public lake, it seems like it would require a lot of special equipment (and expense). I need some sort of anchoring system that I can do through the ice by myself or with possibly one other person. That is why those "Penetrator" anchors look appealing. With some sort of extended pipe and lever on the surface, I am hoping to drive those manually.

 

I have very little access to extra manpower or budget for this. Currently, I have the portable. But, I've already dealt with more damage (booms and mainline) than I think I would have had with individually anchored buoys. I'm also OK with swimming the buoys in at the start of my vacation. I can do that myself without the boat driving required for a portable installation. I really enjoy the portable - but I frequently don't have any help to install and remove it. I have removed my portable myself from a rowboat and it was OK. But, it took a lot longer than disconnecting buoys would have.

[ctsmith]

Ed, thanks for the picture of the anchor wanker. Looks simple and handy. Is that a trailer hitch ball mounted on the top? Can't see it good.

[Jordan]

From this site;

 

forums.jlconline.com/forums/showthread.php?59385-Cost-of-helical-coil-foundations

 

***Prices for installed helical piles start around $150 per pile and get more expensive commensurate with the loading requirements. ***

[mwetskier]

if you can find an old copy of the water skier magazine feb-march 1972 it had a good article about how to put in a slalom course thru the ice. the awsa hall of fame headquarters might have back issues for sale. one trick i was told was to cut each hole thru the ice so one corner of the hole was exactly wear you want the buoy and then use that one corner like a pully to lower the weight to the bottom supposedly this is very accurate.

[behindpropellers]

@skoot1123-

 

Your making this much harder than it is.

 

When they dig the lake they will most likely lay this out via GPS coords. Once that is done they can just lay the course into the file for you. After that you can use the gps to pull your points on the lake bottom and get the course in. Its pretty easy to do when there is no water in your lake.

 

If you need a contact to talk to about this, please drop me a message offline.

 

Tim

[klindy]

@mwetskier I've installed courses like that before and you're right using the corner of the hole as the exact location is ideal. Since gravity would hold a block anchor exactly vertical you can simply lower into place.

 

@MISkier I'd likely opt for a block type anchor (as shown above) installed through the ice rather than the penetrator anchors. The problem iwth the fancy drill in anchors is getting them in the precise location and screwing them in. I'd hate to string all the buoys on it in the spring and find something that needs adjustment. Using a block type anchor you can adjust if necessary and then "pin" them to the bottom with rebar (if you leave a sleeve in two corners. I'd be those penetrator anchors are fairly expensive in comparison as well.

[MISkier]

@klindy, I think the penetrator anchors I'd need are about $25 each. I'd probably have close to half that into a concrete anchor/rebar combination. My concern with the concrete anchors is that they could be snagged and launched right out of the water - any rebar only holds them in a lateral position. Some of the other threads on this forum about launching boat anchors and narrowly missing skiers got me thinking about that. I'd like something with a little more holding power into the bottom, along with a release mechanism on the lines to the sub-buoys/buoys for excessive force. I'd also only have to auger a small hole in the ice for the penetrators. The concrete anchors would require a huge hole. And, I would be trying to move, lower and place the 200lb concrete anchors myself.

 

I agree that the screw anchors have drawbacks with adjustability, but I am not going for record capable and not running tournaments. I have access to other sites for that. This one is just a practice/recreational site. Unless I am a few feet off, it shouldn't be a big deal. If I am within 6" or so, that would be fine. I am planning to assemble and lay the portable course on the ice to mark the locations and assist with confirming the measurements. With only a small hole at each spot, I just need to have the pipe relatively perpendicular to the ice (possibly with a jig to fit over/into the hole) to drive the anchor close.

 

The concrete anchors do have an advantage if certain bottom condition (rock) prevent the installation of the penetrator anchor. That could be an issue. I'm continuing to really evaluate what I am going to do and that is why I haven't completed it before now and have used the portable for about 6 years.

[mwetskier]

@MISkier -if you use a lighter cord for the last 3 feet theres no chance a snag will even move the block before the cord breaks but if you are worried you could launch a weight out of the water some how then i would be really worried that a real solid anchor would rip the running gear out of the boat instead and you prolly dont want that. just use thin cord at the top that can break easy and the boat cant ever snag any thing tuff enough to cause a problem.

[ForrestGump]

@MISkier It won't take long and the concrete anchors will be encased in silt. You are not yanking them out of the water. The lines to your sub buoys will snap first.

[Marco]

As @Shane says, simple concrete anchors are the way to go. We have 30" square by 5" thick concrete anchors that are so sucked into the mud I don't think you could move them if you wanted. 11 years installed with no issues. If the lake bottom was rock, I would be more worried about them moving.

[jwroblew]

@skoot1123 you think you can post your sketch of your anchor system.

[Skoot1123]

@jwroblew - yes - I forgot about that! If I can get to it, I'll do it this week.

[Skoot1123]

Here it is, pretty crude and maybe hard to understand, but it is what I have right now.