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Tom Sawyer

Slalom Course in a Current

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Tom Sawyer

I've been carrying the idea in the back of my head for years and have always came to the conclusion that it would be too much of a PITA to make it worthwhile. For one, it would have to be a portable. I'm all but certain it would get messed with if I left it in not to mention the fact the we can sometimes see daily differences in water levels. This relates to problem #2...the bottom of the river where it would be used is VERY VERY muddy. I think I'd have to buy a cheap flat boat for the purpose of taking it in and out.

Just curious what the Bu Crew's take is on the situation. Suggestions? Ideas? (Other than moving too a lake.)

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aneal000

You can't find a shallow slew somewhere with less current or no current?

I think it would be a PITA for all the above reasons you mentioned. How about Mark Twain lake? No good coves anywhere you could set one up?

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Tom Sawyer
You can't find a shallow slew somewhere with less current or no current?

I think it would be a PITA for all the above reasons you mentioned. How about Mark Twain lake? No good coves anywhere you could set one up?

Less current yes. No current no. Mark Twain Lake sux.

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jgouveia3

our course is on a tidal river, so we get both changes in depth and also a fast current (i'd guess 5 to 7 knots). we have not had any real problems related to the current, although sometimes you get out there and it seams the turn balls maybe be a bit out of alignment from the boat guides (although they all seem to be about the same amount out of alignment). I guess for us it is not that big of a problem, we are out there for fun, and never will have a tournament out there. there are supposedly kits available to adjust for river currents, but we have never used one (the course has been there for 19 seasons now). not sure what the muddy bottom issue would be. ours is muddy, just the 2 anchors touch bottom (if you are using a system like an accufloat), so you just need to clean them off before they get in the boat. oysters, eels, crabs, stray fish, etc are another issue though. we use my fishing boat for putting in and taking out at the start of the season. if you are using a portable course, growth/mess shouldn't be an issue on a ski boat.

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uk_exile

isn't speed going to be a major problme in a current ?

it would make the course easier up stream effectively lengthing it & really hard downstream as it would seem very short

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Tom Sawyer
isn't speed going to be a major problme in a current ?

it would make the course easier up stream effectively lengthing it & really hard downstream as it would seem very short

Not a major problem...would have to adjust PP to compensate.

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edwin
isn't speed going to be a major problme in a current ?

it would make the course easier up stream effectively lengthing it & really hard downstream as it would seem very short

you'd have to adjust Perfect Pass for the changes - add rpms for up wind / current, take rpms out for the down wind / current pass. no problem as long as the times are within tolerance.

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uk_exile

I don't understand. The bouys are stationary & the surface of the water is moving 5-7 knots. That's fast & is about 20-25% of the speed the boat is going through the course. It must make a big difference as one way the skier travels down the course at say 30-5=25 and the other way at 30+5=35.

Am I right or is the whole relative motion thing tricking me ?

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M3Fan

Typically you have to have to add 2 more anchors on a river course- each one attached to a rope on each side of the course which connects the bouy arms at their outboard end. So basically the ends of the bouy arms are strung together, then connected to an anchor on each side that helps the arms resist bending from the current.

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MIKEGOUGH1

We tried a river course down here and did not have good luck with it at all. First, the tides here can have as much as a 2' swing and the river we tried to use is only about 6'-7' deep to begin with which caused some problems with the Insta-Slalom course we were using since it requires at least 5'. We then tried permanent bouys, which worked better, but we did have the current problems. The bouys moved around in the current. Seemed like we never could get ideal conditions. We gave it up after a couple of seasons and went back to our delta course which is in a protected slough.

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jgouveia3
Typically you have to have to add 2 more anchors on a river course- each one attached to a rope on each side of the course which connects the bouy arms at their outboard end. So basically the ends of the bouy arms are strung together, then connected to an anchor on each side that helps the arms resist bending from the current.

we never thought of doing that. maybe we will do it next year. we do some major bending of the arms when the current is fast and the wind is whipping, but usually in those conditions we aren't going to ski anyways. I guess we are pretty happy with our current setup as it is just for practice and fun.

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ibelieve

You can also have the rope that attaches to the bouy arms come in to the main line to avoid the need for the additional anchors. Just create a small loop in your main line before the entry gates and clip the bouy ropes to it. Putting out extra anchors is a pita.

/Steve

Typically you have to have to add 2 more anchors on a river course- each one attached to a rope on each side of the course which connects the bouy arms at their outboard end. So basically the ends of the bouy arms are strung together, then connected to an anchor on each side that helps the arms resist bending from the current.

we never thought of doing that. maybe we will do it next year. we do some major bending of the arms when the current is fast and the wind is whipping, but usually in those conditions we aren't going to ski anyways. I guess we are pretty happy with our current setup as it is just for practice and fun.

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SunriseH2OSkier
I don't understand. The bouys are stationary & the surface of the water is moving 5-7 knots. That's fast & is about 20-25% of the speed the boat is going through the course. It must make a big difference as one way the skier travels down the course at say 30-5=25 and the other way at 30+5=35.

Am I right or is the whole relative motion thing tricking me ?

PP has a WIND setting that can be used to compensate for wind or current. In RPM based modes, it will add or subtract RPMs from your base settings depending on which way you tell the system you are going (manual entry). You program in more or less 'boost' based on how strong the wind (or current) is. Going upstream, it will add the RPMs - you will be going faster relative to the water surface, but ideally the correct speed relative to the fixed course. Opposite downstream. Bottom line is that as long as you satisfy the timing (entry gates to exit gates), the geometry/speed of the pass should be the same.

I am curious though how much different the ski response is skiing with the current vs. against it? Is it similar to having to compensate for wind?

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SacRiverRat

The best solution is to let the course drift in the current, that way you don't have the speed differential. after your pass, just tow it back up stream and do it again Thumbup.gif

Crazy.gif

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SacRiverRat

Probably can't be done... don't bother anyway, just wakeboard and surf, itsalllll gooood Yes.gif

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uk_exile

ok, the speed through the stationary course can be correct but the different ski speed on the water must be really hard to deal with. Almost sinking one way & feeling like really flying along the other direction

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SacRiverRat

ah.. the boat will be traveling the same speed over the water in both directions... unless PP can compensate for the speed the bouys are going by.. maybe it can (I don't use the skier version)

I say just use it up stream the bouys will come at your slower than normal, it'll be like a handicap ;)

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Toby
ok, the speed through the stationary course can be correct but the different ski speed on the water must be really hard to deal with. Almost sinking one way & feeling like really flying along the other direction

or will you be going faster up stream???

going into the current you will feel faster than you really are because there is more water traveling under your ski and vise versa down stream. it takes time to get used to and i can easily feel the difference.

think about it...

Edited by Toby

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Tom Sawyer

Guys,

I wasn't planning on installing a course with world record capabilities, I was just looking to have some fun. I packed my slalom ski in the boat all Summer and probably only rode it a half a dozen times..once you've been in the course, open water slalom doesn't do much for you (or for me anyway.)

The bottom line is that it's wouldn't be worth my trouble. Like I said in my op, it would have to be portable...way too much of a pita in the current to make it worthwhile.

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jgouveia3
I am curious though how much different the ski response is skiing with the current vs. against it? Is it similar to having to compensate for wind?

i'd say yes it is like compensating for the wind, very similar.

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SacRiverRat

ok, the speed through the stationary course can be correct but the different ski speed on the water must be really hard to deal with. Almost sinking one way & feeling like really flying along the other direction

or will you be going faster up stream???

going into the current you will feel faster than you really are because there is more water traveling under your ski and vise versa down stream. it takes time to get used to and i can easily feel the difference.

think about it...

Yes, if the PP can compensate, and correct the boat speed within the course, then you'll be traving faster upstream (normal speed + current) and slower down streem (normal boat speed - current)

Though if you just set the PP to compenstate based on RPM or boat speed on the water - you'll travel at your normal speed, with no impact from the current .... except the pesky course will come at you faster going downstream, and slower when you're going up stream

You're choice which is worse - Just depends on how strong the current is. May not be that big of a deal anyway, and like you said, just for fun.

shoot, if you wanted fun, you'd just go wakeboarding Biggrin.gif

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