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Discussion Starter · #1 ·
Well I want to put a ski pole on my boat. Now does anyone have an idea how much pull to expect from a ~200 or so pound skier? I am going to scratch build the pole because nothing off the shelf fits my requirements (I want to bolt it to the front of the engine/stringers, but the pole needs to be removeable and mounting system needs to be contained below the engine hatch.)

At first I figured 400lbs pull was a safe figure, but then after thinking about most ski ropes, I`m thinking theres no way they would hold 400lbs of force. So does anyone have a guess?
 

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What are you gonna be doing with the ski tow? Towing tubes would require a stronger tow. If you are 200lbs and are slalom skiing and are really tearing it up you create a lot of force (pull on the boat) when you cut around a bouy or carve in a nice free ski. When I ski I can put a hurtin on my boat when I carve and I just use the kind that mount to the back of the engine. My buddy had a pole installed on the front of his motor recently and it works great and is removable. Give Bergeron Marine a call. They are in Mesa, AZ. They can ship you one that will suit your needs whatever you are towing.
 

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I'm No Expert
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When I ski I can put a hurtin on my boat when I carve
Ya, no kidding. When my dad ski's behind my boat and carves you can feel the boat instantly slow down and it's not just alittle bit. You wouldnt expect the boat to feel like that just by towing a guy behind you on a ski. Would be interesting to find out how much force is really put on that rope with a good ski'ier who can carve behind it!
 

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We build our 47" poles out of 1 3/4" round bar and I have yet to see one bend. I weigh well over 200 and cannot bend it doing my best submarine impression :D

I can pull and 18 foot boat around pretty good but cannot bend one of these poles. Gives you a starting point for material size at least.

I wouldn't tow a large boat with one though.
 

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A hard slalom cut is sort of a cross between a one armed curl and a dead lift (using weight lifting exercises). Think about what the max weight your body can lift during one of these exercises. I'd say a really hard cut is somewhere between 150 and 250#'s. Any more and you would not be able to hold on or your arms would rip out of their sockets and you would die a bloody and tragic death.

Deep water start is probably more force than a cut. But again your arms and torso can't survive much more than 100-200#'s (or else the only people who could ski would be pro weight lifters).

Hole shot with a tow tube is probably more force and hole shot a towed boat is even more. Your 400# design number is high but reasonable for design. I think the ropes will hold a lot more than that.
 

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Discussion Starter · #6 ·
I have no plans of towing tubes with it. When I tow tubes I will use the stern eyes, no need to have a high tow point for them. But I wanted to add a removeable pole to ski off of. I had been planning on using 2" aluminum pipe for the pole, which should be plenty strong. The only interesting part is the height. I have approx 2.5 foot from the bottom of the bilge to the bottom of the engine hatch, and I want all of the bracing contained in there. I have to wait till I get the interior back and reinstalled, to check, but I think the pole needs to extend at least 1.5 to 2.5 foot above the hatch. I want the pole to be above the passengers heads......just incase I decide to go around the boat:)devil. I was going to use 1" rigid pipe to brace to the stringers and engine mounts on the bottom of the pole, and then back to the heads and intake just under the hatch.
 

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I can give you some exact numbers to work from. In the mid-1970s, I did annual water ski evaluations for Powerboat Magazine (July issues). Each year we went with four of the top slalom skiers (two males, two females) in the country out to Dr. Horton's private lake in Newberry Springs, California with 30 to 40 of the newest slalom skis on the market. Part of the evaluation procedure was a max-out slalom course run at 36 mph with as short a line length as the skier could manage. In order to record the maximum "pull" we used a mechanical torsional dynamometer with a tattletail needle which would record and preserve the greatest amount of "pull" on the ski-line and pylon in foot/pounds. We hooked a short piece of ski line (about 18") from the pylon (mid-boat) to one side of the dynamometer, and then attached the rest of the ski-line (60' or less) to the other side of the dynamometer. Interesting numbers. Skiing directly behind the boat in the wake (no cutting or movement) the reading was between 70 to 100 ft./lbs. depending on the size (length) of the ski and weight of the skier. The slalom girl skiers (Deana Brush and Camille Duval -- in the 120 to 130 pound weight category) pulled in hard slalom turns in the 330 to 360 ft./lb. range. Chuck Stearns (about 160 pounds) pulled up to 475 ft./lbs on a short line. The most aggressive and hardest pulling skier was Bob LaPoint (world slalom champ at the time and about 205 pounds) hit over 650 ft./lbs. on several runs. It was actually a pretty simple test to do -- not sure why some of the other water ski magazines never picked-up on it. I have heard from companies like MasterCraft and Correct Craft that they used to engineer and test their ski pylons to withstand a "pull" of up to 1200 ft/lbs.
 

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As an added .02 all the pylons we've built for manufacturers of the center pull variety have been made out of 2 1/2" round bar. The 1 3/4" I referred to earlier we use for outboards to clear the motor. We've sold literally thousands of the 1 3/4" poles over the years and I've never had one come back bent.

I think the part to worry about will be your mounting / bracing vs the pole itself.
 

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Discussion Starter · #11 ·
Thanks for the pics sleeper. Those are very helpful, that is similar to what I was looking to make, but I was planning on bracing it off the engine mounts and heads/intake, so it looks like I should be ok.

twocents, thanks for the input. I knew someone somewhere had to have checked the pull. I figured 400ish was probably safe for recreational skiers....no one I know is even close to a pro lol.

rexone, Yep I was never really worried about pole strength. I was pretty sure that the pipe I was planing on using would be plenty stout. Just needed an idea of how much pull to expect so I knew how crazy to get bracing it.
 

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That's a nice poll Jon.....Just Sayin....
Hey now......don't be getting "fresh" with me........Just sayin'


But I have heard that before :)grn

S CP :D
 
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