DIY - Submersible Waterski Course - Building your own sinkable waterski course.

Basically, you need:
- 24 5 gal buckets
- 24 wheels/tires (approx 10” - that will fit in bucket)
- lots of gravel (17lbs in each bucket) Recommend pea gravel. Fine Sand has a way of disappearing over time.
- lots of brass fittings (T's, couplers and stops)
- 1 Schrader valve (like on a bike inner tube)
- lots of air tube (we used semi rigid tubing and ran it all the way to the shore)
- some extra stainless cable (if you want to sink the 55m's)
- 30' or so of flexible clear tubing

Construction:

Fill 22 - 5 gallon buckets up with approximately 17lbs of rock. Put a small wheel (approximately 10") inside the bucket with the rocks.

Note: You will have to experiment with the proper amount of gravel in the buckets to make it sink, but not so much that it will not come up. For us, it was 17lbs.

Drill a hole in the top of the bucket and run a air line to the wheel. The clear tubing slips tightly over the valves on the tires. Only need approximately 6" of this tubing. Use a coupler to connect it to the semi rigid tubing. (i.e. use T's to run the air hose to all the buckets.)

Each bucket is tied to the PVC under each buoy. Do this to all of the buckets/tires. Connect all together with T fittings. Run one end of the hose to shore or to a buoy that stays up. Put a bike Schrader valve on it.

For the 55m's, we ran some stainless line along with the tubing out to the 55m's. We then took some rope, with a cinderblock attached, and anchored it before you get to the 55m's. This keeps tension on them when they raise and lower. You have to run a stainless line along with the air line between the gates and the 55m's. Having a rigid line is the only way to ensure the distance (55m) will remain constant.

Remember, the buoy is basically floating. So, by having tension on both sides (stainless line to course and rope to anchor) it will raise and lower with relation to the course. An easier way to do this is just use anchors and sub buoys for the 55m's. You just have to find them each time to attach the buoys. I recommend you suspend the course under the submarine. Otherwise you will constantly be cussing fishermen for piercing the lines when not in use. Makes it too easy to snag! See diagram below:

Comments:

I went up there today and it really works awesome! When you get to the spot, you see nothing except the 55m's (working on that). We pulled up to the shore, found the end of the hose and used a battery powered compressor to pump the system up. It was really cool to watch the buoys pop up one at a time. The whole process took 9 min.

When we were done, we took the valve off and within 4 min, all the buoys were approximately 5-8' under water.

A. They used strong zip ties from the PVC/mainline to the handle on the bucket. (The handle of the buckets are tied with string to the PVC.)

Note: Make sure those pail tops are secured tightly!!

Q. When the course floats up - are the 5 gallon buckets still hanging below the PVC or do they float above the PVC?

A. The bucket stays below the course. It still has weight even with the tire filled with air.

A. The buckets have not gotten stuck. Someone is skiing 4-5 days/week, so it has not stayed on the bottom for long.

A. The rocks are on top of the tire. Also, make sure the tubes go on top of the sand weight not under.

Note: The wheels you select have to be able to collapse under water pressure. If not, there will not be enough volume change to let in more water weight. The more volume one can change the deeper the system will be able to go and the quicker it will respond.

A. I don't think the size of the tubing matters. They used approximately 1/4 ID semi rigid tubing. One of our members had a ton left over from a job so no cost to us. As far as how much - a whole !#@$ load. It runs from 55m to 55m then goes to a shore line approximately 300' away.

A. We used a cordless air compressor - (http://www.lowes.com/) A portable tank does not have enough air.

A. Yes. We have 15-25' of water, but the bottom is pretty smooth. There was some discussion on this board about whether you could make it neutrally buoyant. I think the consensus is that it is not easily doable (too many factors - water temp, air pressure fluctuation in buoys, etc).

A. Someone cut the air tube and some water got in. We are struggling to deal with it. The course still goes up and down, just takes longer. I want to try to hook up one of those cordless oil suction things to it. I imagine we will only sink it 1/2 way when it gets colder. I would assume it would be as simple as letting enough air out so that it goes under the water a few feet, then close the valve. Right now we just open the valve and let all the air out.

What WILL work, is to sink sufficient anchors at each relevant location (i.e., the "Accusink" submarines) and have an attached sub-surface buoy to which the submarines are tethered. When you sink the course, the submarines can only submerge to the depth of their tethers, after which they will remain supported by the sub-surface buoys. (BTW, this idea does work, but it seems like an awful lot of effort – your suggestion of diving to retrieve the course is probably the easiest and most workable.)

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