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Self-Leveling Buoy system design: Design feedback please


Aguavidapirate
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I've been searching through history of tried-and-true self-leveling buoy systems. Our lake varies a lot (~18" throughout the season), and nothing has worked great so far. The systems that seem most common are types of counter-weights inside a piston, sometimes requiring a dry lake to install (not an option for me, at least this year).

 

So I came up with the following design, which could be installed anytime and seems quite simple. I can't find any problems with it in concept, but since I can't find where someone else has tried it, that usually means there's a fatal flaw...

 

Self-Leveling buoys using counter buoys and pulley

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For a course buoy inflated to 10" in diameter, I calculated that we'd need the equivalent of a ball inflated to 8" diameter to provide the force required to submerge the marker by 50%. We could simply use a less-inflated ball or use a float that would be approximately the same volume, but an oblong foam buoy is preferred so inflation doesn't vary over time. The pulley would need to hold up in water over time, and would need kept clear of weeds so it doesn't bind, although I believe the buoys would self-correct pretty aggressively even without the pulley rotating freely. In general, it seems like a pretty simple and low-maintenance design. Has anybody tried this? Any reasons you can think of that might cause problems?

 

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Depending on the length of the buoy line and the sub-buoy line, there’s no way you’ll keep them from eventually getting tangled unless you guide them better than just a pulley at the bottom. As mentioned before, any failure of any part of the system means a big job sorting out what’s left. Unless the lake is 4-5 feet deep where you can stand on the bottom.

 

Wouldn’t a piece of surgical tubing be an easier solution? If you can use an anchor line with a sub float about 3-4’ under the surface then use a long rubber surgical tube up to the slalom buoy. Use a clip that can be adjusted at the buoy on the surface. Unless the lake varies frequently (every few days) it shouldn’t take more than a few quick adjustments each season. Otherwise the rubber tube should be able to adjust for 6”+/- without adjustment.

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I would use a stainless steel ring instead of a pulley, but be sure the ring is totally smooth with no catches or burrs, etc that can wear/cut the line. The pulley mechanism can get jammed (especially with zebra mussels, etc.) and it may be easy for the buoy line to slide off the pulley and jam.

 

We had a self leveling system at our club 6 years ago (a different design). There was always one problem buoy or two that never really worked right. We removed the entire system and went to the surgical tubing method that @klindy mentioned. We spent far more time messing with the self-leveling system than we do making a couple adjustments per season.

The worst slalom equipment I own is between my ears.

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We've used the reverse of that for years. We don't use pulleys, but simply clip the buoy onto the rope with a counterweight hanging down instead of the float pulling up to create tension. That way if you need to clean weeds or other gunk off, the "mechanism" is within easy reach without diving (plus, where we are muskrats will chew on underwater floats). On one of our old courses, we did use pulleys, but they're unnecessary- with plastic or brass clips, we don't see any wear on the ropes
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This system is tried and true and works well. I know a lake in Georgia that has used this system for 20 years with no problems.

 

If you want to use Wally buoys with less air, cut down your counter float. Never over-inflate your turn balls to adjust the counter; adjust the counter to get the surface buoys the right height. As you’ll see below, you’ll want to use a foam counter, not an air-filled one.

 

Use a high quality stainless steal pulley like would be used in sailboat rigging. Expensive but as I say, will work flawlessly for 20 years.

 

The one thing you do have to watch is that the counter buoy doesn’t displace the actual buoy. To do this, put a vertical piece of pvc pipe through the center of the counter and run the line from the surface buoy through the pvc to the pulley and back up to the counter float.

 

See you in 20 years.

Lpskier

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Thanks all - extremely helpful!! Our lake is varies 12-18 inches every 7-10 days during the season, so even needing to do minor tweaks is a pain.

 

@skiep - I like your piston design - we were considering something similar, but where the pipe was buried. Your system could be installed in a filled lake though, so major advantage there. BTW - I recommend taking down your phone number - web crawlers will eventually find it and you'll start getting lots of robocalls :)

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I had success with zip tieing a plastic pulley to the buoy.(found at lowes designed to work with clothes lines and were cheap. They were also about 3inches in diameter. As mentioned above the cheap metal ones dont work and the narrow diameter plastic ones don't work. The sail ones like Lpskier mentioned would be the best. Plastic ones... cheap, but lasted until I sold my lake. Didn't think they would but they worked well.

I am cheap so I used plastic 16 oz. soft drink bottles filled with sand. A wire run through the cap provided a way to attach the rope to the counter weight.

As mentioned before when we first tried it we found the rope down to the anchor and the counter weight part of the rope would get tangled. We fixed this by using a length of PVC pipe that was about as long as the bottle zip tied to the bottle.(rope from the anchor up to the pulley goes through the PVC pipe)

This is cheap and worked excellent. For the obsessive compulsive ones of us, which seems to characterize most of the skiers on BOS, reality is that you will lose 3 inches of tolerance in buoy width. This would not be record capable. Also this not a good design in a deep lake where it would be difficult to retrieve the system if the buoy gets cut.

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I've revised the design based on the feedback. I'm hoping to not be tweaking this all season, so am really appreciating learning what's bound to go wrong over time. If I understand the feedback correctly, the revised design should incorporate the main recommendations for this type of system. I also posted some off-the-shelf products for the system.

 

 

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For the off-the-shelf materials, it looks a 5"x11" deepwater float would be a little undersized to submerge a 10" ball, so it could be augmented with additional another small float and then trimmed down. From there, I'm thinking minor tuning of the system could be done at the small float that's used to keep the system afloat when a ball slalom ball is knocked off (i.e. swapping out slightly smaller or larger floats).

 

The main thing I prefer about this system over the counterweight is that unless the counterweight is buried, there's something in the water for the prop to hit that's heavy. Not a worry for experienced drivers, but we have kids that will be driving the boat on our lake before long ...

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@Aguavidapirate for counter weights we use large galvanized bolts taped together. That way they would hang vertically and be trouble free. No need for pulleys to have issues, the 1/4 yellow poly rope is cheap and readily available. Recommend using quality zip ties, the cheap ones don’t last.
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@RichardDoane's drawing is our system. @Aquavidapirate, I've been skiing on courses of that design for way longer than I want to admit and no one has ever hit a counterweight. My personal course has red solo cups filled with concrete for counterweights, but we've used old sash weights and all kinds of things. The red solo cups are just about perfect if you're running your buoys at minimum dimension or partially filling with water. And they're cheap!
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This is what I did for my lake that fluctuates about 12" max. It will work for more fluctuation by simply using shorter pvc. I used 3/4" dia electrical PVC on the ropes and snap tied them together as the ropes will easily twist . You can run as many calcs you want to determine how much sub-buoy you need but trial and error is the only way to get it perfect. Some pulleys had a little more resistance and some buoys had a little more or less air. I undid one end and kept cutting the sub buoy shorter from my jon- boat to get it right. I found the hole in the sub-buoy is the best way to keep things in perfect alignment and to keep the sub-buoy "out of the way". I did this for all turn balls and gates. I left the boat guides alone as they are not as critical and are on a bungee that can quickly get adjusted those few times a year. I have also found that even if you have a buoy that stays slightly below the water (like the right hand gate ball after you hit it on the previous pass), it will come back to the surface after the next pass due to the wakes shaking the buoy back up. The stainless steel pulleys (McMaster Carr) are attached with a stainless clevice on the eye-bolt anchor. Attach the end of the rope to the sub-buoy using a large 8" long galvanized nail around the loop end of a fidded rope. A knot in the end of the rope will get in the way of the rope that goes to the buoy.

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Correction: I just noticed that the rope in the photos does not actually wrap around the pulley itself, which I hopefully corrected before attaching to the eye-bolt. Also, I could not find those pulleys from McMaster Carr since its been about 8 years. Check out

e-rigging.com item number 51647105.

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@skiep has a very good system. I use a system indentical to your design that Slade Cole engineered. My best advice is to get the green 3/16 nylon rope from HOme Depot as it doesn't twist. If your rope begins twisting between the pulley and sub buoy, it will not self-level properly. Of course, the sub buoy has to be the right size in order for the course buoy to be at the right height. The only issue other than twisting that I've had is that I need to tweek the design for the few buoys that I have in shallow water; 3 to 5 feet. In this case the sub buoy will hit the buoy and not self-level. Good luck; you're on the right track.
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