How Long Is The Optimal Jump Rope Length?

[chris_logan]

I was perusing social media a couple days ago when I came across a post by Ron Goodman about experimenting with different length jump ropes. This topic magnetically drew me in, and I thought it might gain a little more traction/commentary on BOS. See original posting below:

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Ron Goodman : Had a rip with an 85' rope today...just added 10' of Dyneema to my mainline. Felt pretty good...might be a bit long. Will try 80' tomorrow, then 1' increments. This is a conversation that needs to happen. Why is the jump rope 75'? Seems everyone wants them maxed out on length...which suggests they're to short. Why not 76'? Or 82'? Time to test and find optimum for each speed.

 

Micah Ping : Why even regulate the length of the rope at all?

 

@Rdodd : Good call !

 

Scott Snape : I agree as you can run the boat wherever you want. One consideration is safety. Some of the sites we ski at you come very close to objects on a 75 foot rope. 80 plus might have you colliding with those objects. Charleston is a prime example. When you turn for the jump you are in less than 2 foot of water. 5 more feet of rope and you will be turning in sand.

I said I would never jump there again as the shallow water lifts the tails ( especially the right ski) driving the tip in which makes it almost impossible to get you ski around. Last time I was there I got my driver to run narrow and when he felt me set my skis move out to split. It worked but not something I want to repeat.

 

Ron Goodman : It's a good point Scott. My thinking is that it's a self correcting problem however. There are sites I won't jump at no matter what rope is used. Haha!

I like Micah's point...why measure at all? If we can already adjust boat path it only makes sense to mess with ropes as well. We already use our own anyway so this is a tiny step. Each skier could figure it out for themselves, no different than how much spectra to use. Maybe Jrs or slower speeds would like a shorter rope??? Ploppers just starting out...shorter? Food for thought. Gotta try...

I can say 85' at 35mph felt to long. Just an opinion of course. Boat ran right up next to 60's and I wanted it wider. What I did like was the rhythm out of the turn and comfort it gave for finishing turn. Bit different off the ramp but I think that's boat path.

I'll try 80'. My gut feeling is it'll be better. We'll see. I'm gonna try though...and report back.

Point of all this is two things. First is to make jump better/safer, and second to make tournaments easier to run from a tech standpoint.

 

@Ham_Wallace : I have always liked my 83"!

 

@The_Krista : We get to pick our preferred length in slalom and trick for optimal performance ...just saying :smile:

 

Alex King : Trick yes, slalom no? You get to choose where you start but not where you finish! Haha but good discussion!

 

@The_Krista : Haha you get to choose what is best for you to be able to ski your top performance...(kinda)..work with me here Alex! Also...the length of the rope in slalom is an integral part of comparing scores so some uniform system of measurement is necessary but still your personal preference for optimal performance is your initial choice ... The length of the rope is not used in calculating any results for trick or jump... :smile:

 

Ron Goodman : My thoughts exactly Krista. Jump is scored on distance alone. The 75' rope length was mandated so long ago that the logic is irrelevant in today's jump event. Skis were wood, short, and unstable. Bindings were basically flip flops bolted to the wood planks. Slings didn't exist. Ramps were wood, short, and dangerous by today's standards. Boats...hand driven twin rigs.

It's time we take a serious look at the ropes and the length we use.

I'm leaning toward total skier choice for both materials and length. I'm a Guinea pig...and will report my thoughts as they develop over the next few months. I encourage others to do the same.

 

Jeff Rush : Would longer or shorter ropes affect how the switch engagement would need to be calibrated? Would ZO need to add the 1,2,3 principle, like in slalom and trick, to the jump letters to adjust for rope length? 1= <75', 2=75', 3=>75'? Why can't the switch be skier supplied option to adjust to their spec'd tension instead of the standard 120 lbs?

 

Ron Goodman : No. Switch works the same. Can't tell any difference.

 

[Edbrazil]

Interesting point. The 75 foot spec goes way back to the 1950's, and maybe 1940's. Of course,

lots of sites can't fit a longer rope, and 75' is borderline at some sites. Lots of private lakes

have been designed more for Slalom, with Jumping somewhat of an afterthought.

[eleeski]

Standard physical parameters are a part of measured competitions. Ramp settings and speeds (timing) have to be the same (within tolerances) for all skiers. Since the rope is an integral part of the physical leverage, it needs to be consistent throughout the event. Giving a skier extra rope seems equivalent to giving extra speed.

 

Boat paths and ZO settings are skier chosen to put the skier on the ramp safely and with speeds in tolerance. The rope length is a completely different variable (physics of the lever arm at the end of the rope). A shorter rope would not offer a physical advantage over the standard rope so allowing ropes less than 75' should be OK if the skier prefers (like choosing a slower speed is OK).

 

Many lakes were carefully designed for safe clearances with a 75' rope. A longer rope would reduce the safety margin in those clearances. There are few enough jump sites - we don't need to lose any more.

 

Of course, if this is an out of the box experiment (like ski flying) then it is very interesting.

 

Eric

 

Disclaimer: I am the world's second worst jumper.

[chris_logan]

I think there is currently room for improvement over the 75'. I would like to see some mathematical analysis of the acceleration curve, based on the pendulum effect, to see where acceleration ends with relation to length of rope. Logic tells me that acceleration would end at the bottom of the pendulum swing (behind the boat), however when you have skis on edge we all know this is not necessarily true.

 

Swing radius also plays a large role with this as you don't want to be traveling more right to left than you are forward when you reach the ramp. There is a limit to how far out you can move the boat to compensate for this and A)still have lake to ski on & B)maintain a straight boat path w/o putting in another set of boat guides outside the 60s.

[klindy]

@eleeski Im surprised at your position. For tricks you've advocated for wakeboards, longer/wider skis, pylons, etc for years which obviously makes conditions potentially different between skiers.

 

Currently a jumper can bring his/her own rope which is made up of various lengths of different composition rope which changes the ability of the rope to stretch. Certainly that has potential to make a difference?

 

I like it that Ron Goodman is experimenting with rope length. True that some lakes are designed to work with a 75' rope but that's like saying that it's too hard to fit a 6 buoy slalom course in this short lake so let's make it 5 (or 4 or whatever). If xx feet is determined to be optimal thru calculations and/or experiment then the sites which can accommodate that overall width will be ready. Those that can't either make some changes or can only use a shorter rope.

 

Frankly I like the idea of challenging the status quo.

[eleeski]

From a purely physics standpoint, the long rope should, give an advantage in jump distance. Only the most skilled will be able to take advantage of the longer rope but it would not differentiate any of those top jumpers. Distances will go up without any true increase in skill. At the expense of safe clearances in the best man made sites.

 

Unlike my trick proposals, longer ropes will not attract any new skiers. Nor is there any clear advantage (line tricks, toes and many others are as much harder from the tower than flips are easier). A rule change to longer jump ropes would shrink the sport by restricting available sites.

 

The research and discussion about the optimal rope length is really good. If a rope shorter than 75' turns out to be best, then I fully support skier's choice of rope length. And it is a fun topic.

 

Things need to change but scores don't need to be padded. Especially if we lose a few quality sites.

 

Eric