Sinker course random thoughts

[Waternut]

A few guys and I keep discussing the option of a sinker course. We currently have all the anchors in place but we are no longer allowed to leave the course out on our lake. The course is in 5 to 8 feet of water so I was under the impression that the Wally sinker course isn't really an option at those depths.

 

So my next thought was have a smaller weight and inflate the buoys to raise and lower the system. That way the whole course could be lowered much deeper without the worry of boats hitting it. The only concern I have with that option is that most ski buoy have the inflation hole in the middle instead of the bottom which could be problematic. I have seen some mooring style buoys that are 8" diameter and have the inflation hole at the bottom that would work but when I contacted the company they said they were much heavier duty than slalom buoys. Could probably be used for boat guides though.

 

Am I being crazy? Anyone have any other ideas?

[thager]

I think it is doable. Since you have permanent anchors there is no worry about pvc arms so even in 5 ft water if sub/wt is at 2.5 foot below buoy, sunk would be 2.5 below surface. Using the buoy as the float would help but will introduce water into system if cut.

[Edbrazil]

Interesting concept. First, do some small-scale experimenting. The Polyform S1 buoys

have their air hole/valve at the bottom, so a possibility. You could also attach the

Wallyskier air bags near the end of the PVC arm, but not under the buoy. And, maybe

use weightlifting weights vs. the sandbags for weight.

Again, experiment first, such as right next to your dock. I foresee that getting water in

the system may become a problem.

I've thought about using the Wallysinker concept and some materials for a bottom-

anchored course, but never followed through on it.

[Waternut]

Thanks for the buoy recommendation. I would definitely do some experimenting at my dock especially to get an idea if using different style buoys wold be a problem. Purging water would be a pain especially if it gets in the other buoys but I think it would only be a problem if a buoy got cut when we weren't skiing. If a buoy got cut while we skied, the rest of the system would bleed down and just push air out until everything equalized. You'd have to fix it immediately but we typically did anyway unless it was a boat guide and then we waited until the end of the set which may still be possible....experimenting would help there too.

[fu_man]

Funny. I have been sitting here this morning trying to think of ways to install a sinkable course into shallow water as well. Your idea intrigues me. However the main issue that I can't figure out is how you would get the air out of the buoys once inflated. They will be sitting on top above the water line. How do you sink them without manually draining each one? I can't see "sucking" out the air with the pump. You will collapse the air lines before any air gets pulled out out of the balls. Am I missing something? I don't have a clear picture of how the Wally sinker bleeds the air out either so maybe I am missing something.

[Waternut]

@fu_man I'm pretty sure you're over thinking it. If you try to force a sealed system underwater, it will resist. If you try to force a system underwater and you have an opening, the air will come out. Either way, if your lines go 10 feet underwater, the pressure on the outside of the air lines is way more than a full vacuum so any lines you use would likely have to be vacuum rated.

 

Can anyone confirm that the wally sinker air lines are semi-rigid?

[mwetskier]

1/4 inch plastic water hose would be very durable and will not collapse even under full vacuum -which is only 14 psi. you would want to incorporate a water trap in the vacuum side to prevent sucking any loose water through your compressor / vacuum pump. this trap is simply an air tight tank with a drain valve on the bottom.

[gsm_peter]

Would it be feasible to one anchor per boie and some part of the rope being a bungy cord?

One could then potentially pull down each boie to 'the bottom' independent of the depth.

 

Stupid question a bit off topic but why is boies consider to be dangerous and especially during the night?

[Waternut]

@gsm_peter Not sure if I follow what you're saying but I think I do. I have looked into the option of just pulling all the buoys down with pulleys and a winch of some sort. However, at around 15 lbs of floatation per buoy, I was worried about pulling my anchors out of the ground. Let's not forget that we've got at least 22 buoys so 330lbs plus friction and drag in total. You'd also need a really really strong anchor as your central winching point. You could have multiple winching points but that's also more buoys to attract attention.

 

Totally doable and wound be really quick and easy but you'd have to redesign the anchors in a way that they don't move or pull out when you start pulling.

[Jordan]

what about a hybrid system where you sunk the arms and the sub-buoys but unclipped the balls? More work...but faster than a full removal.

[Waternut]

Well with this setup I don't have any arms since it was a permanent course. However, the amount of time and enegy to find, clip, and unclip 22 buoys is more than I want to deal with. If it was just the turn buoys and entrance gates, that wouldn't be too bad but even then, it's a lot of work when most of the time it's just 2 or 3 of us skiing.

[aupatking]

Anyone have experience with the sinker course in a brackish water environment? Also, @Waternut what depth does the water need to be/how far from the bottom do the submerged parts sit?

[Waternut]

@aupatking Are you asking what it should be in a normal sinker or how far I'm expecting my buoys to sit if I make this system work?

 

I would expect my buoys to sit around 3-ish feet underwater.

[aupatking]

@Waternut either, or both I suppose. I've got pretty close to the same depth issue you have, so I'm wondering what would work best.

I'm fairly certain I'm going to have to buy the stainless EZ Slalom setup from Ed,but I'm open to other options, especially faster, easier, cleaner ones. I'm planning on a phone call to Wally tomorrow between flights. I have to tell him @Horton loves his balls.

[aupatking]

@Waternut for yours to work, what about going way low tech, and just run your sub buoys at the depth you want for safety with sturdy anchors and lines with a bowline loop on top and bungee through the loop. Run a very long piece of thin poly from bungee to bungee end with 1 ounce sinkers every now and again to keep that line on bottom.

You could leave 1 buoy attached to your slack line and just follow the line and clip your balls.

Permanent but sunk.

I'm absolutely certain I'm missing something blatantly obvious.

See art work for line path

Or

 

[Waternut]

Yeah I have considered that and it may be a more valid option than trying to do a sinker course. The only downside is I'd have to redo all the anchors and our lake is a muck bottom.

[aupatking]

My river is muck too, but where I am near the bay, is brackish. If I leave balls under water, they'll have barnacles in no time. My biggest problem will be setting anchors

[aupatking]

My biggest fear with an underwater line, uniting the sub-buoys is that I'm creating a net. I want to be certain that I have enough slack to give ample depth that the tow boat can leave the course path at any point and not eat the line.

Sorry @Waternut I just typed this and realized I started hijacking your thread

[Waternut]

No big deal. Ideas and concerns even if they are your own problem can still produce meaningful insight. One thing I used when restoring some anchors that were missing was a laser measurer. I even used one to shoot where one of the turn buoys needed to be. Helps having extra hands and it kind of needs to be fairly dark to shoot long distances but I'm impressed with the accuracy of those things.