Physics question

Does anyone know how much force a rider exherts on the tow line? Like if you put a fatty pull scale in the line what would it get up to on deep water starts and cuts and stuff? I was thinking about this the other day becasue I'm building myself a new pylon, I'm not worried about it not being strong enough but just got to thinking about it.

Not sure, but I know a standard tow line has a rating of around 2000 lbs. When I say standard, I mean a crap ski line, but still a tow line none the less. I would say around 10 X the weight of the rider on a very hard cut with a very loaded line. As far as deep water starts, depends on the rider. If done right, not much. If done incorrectly, could be up to 1000 lbs, but most of the time the rider lets go before anything like that happens.

Yeah, I was thinking about it before when I was debating about building my own pylon. The way I see it is a person could only exert as much force as the persons hands could withstand, otherwise they'd let go right? I figure most people would be able to go beyond 500 lbs, most people probably wouldnt even approach 500 lbs. Think about how much weight an average person could pick up, probably a little more than their body weight.
If you look at the other pylon designs out there you can see support lines going from the top of the pylon to places around the boat, these help to balance out the bending forces on the pylon so it is only undergoing compressive stress.
Hmmm, I got a little technical there, what I'm saying is that as long as your pylon has some supports running to the back, and a cable running to the front and they are secured well, and are taught, then as long as you dont go making your pylon out on styrofoam youd be ok. Well I'd use something like a 40 weight chain link fence post. Those come in any length you want, are easy to get and are very strong. Would probably run you around 20 bucks at your local fence supply store =)
Good luck=)

A few years ago, slalom skier Bob Lapoint, the world record holder at that time did just that, put a scale on the pylon end of his rope. During a pass at 39 off, he exerted over 800lbs pull.

no way is it 10times the weight of a human. Not a chance unless youre superman!!

I've read somewhere that 500lbs is the max force.

Well Harry I AM SUPERMAN!!!! Anyway, I was just guessing. I guess it would be as much as the rider can hold on. But would you say a tube exerts more stress? I have been on a tube and had a supposed 2k line snap. It was not freyed or anything, so what's your take on that? Besides we tube at 40 mph...

I would think a slalom pull would be much greater than a board pull and with a high rope attachment even less.

Back when wakeboard ropes were 1500 lb test I broke 2 of them. They typically break when the boarder falls. During that instant of impact the load goes way up. I think this is the reason several years ago wakeboard ropes jumped from 1500 lb test to +2000 lb test. Before we bought our tower I designed our pole with cables. I just designed everything to be stronger than the rope, so that if the fail point was the rope.

Skiing made me board,
Lyle
Chrome Dome Industries

the test strength on a rope is based on everything being perfect. As soon as you add any sort of joint it weakens the rope. Any time the rope gets kinked or knotted it can be damaged and sigificantly weaker. Just time will weaken the rope, and exposure to sun will dramatically degrade a rope.

I have used the weight machines at the gym to simulate the pull for wakeboarding. I would estimate that it takes about 50 pounds to pull my 190 pound body along at 22 MPH. The pull getting up is much higher, perhaps 100 pounds or so.

Rod