wilecoyote

My .02. If you are talking a tapered shaft, and it's been properly lap fitted you may need to add heat. I went the extra mile with my prop, lap fitted it and they pre heated it before seating it. It was a bitch to get off. Made my own 3 bolt puller and heated it, I was beginning to think I wasn't getting it off. And as always, my personal PSA ... Lap Fit the prop when you put it back on. Poorly fitted props are responsible for a lot of broken shafts.

It's been discussed here before, but I think hydrofoils could be awesome tow boats. The problem lies with draft, trailering and weeds.

2 years in the course wearing contacts for me. Ski average about 5 sets/week. I've lost one in a yard sale fall so far. I will say though that it seems to be random but like others have said, sometimes on a deep water start they'll get all messed up and vision gets pretty bad. No biggie though, when you see more than one buoy, just take the one on the left. Something not mentioned here so far, you must wear dailies only if you are skiing, monthlies are a no no.

@Orlando76 if you listen as he's getting ready to go, he says something to the affect of the driver just pins the throttle for the whole pass.

I'm with you @jercrane pylon mount would seem to be the best. But that's because we all here tend to forget that pylons don't exist in the recreational boating world.

I'm surprised that the developers haven't chimed here but no, there is no chance to hit the skier so long as the software is written correctly. They said it's gps based, so if it were me, as soon as the boat speed dropped or the course direction changed more than say 10 degrees, it would stop firing until the driver reset the system. As @Horton said this is a very neat thing for aspiring slalom skiers, it's not designed to replace a physical course.

@OldboyII I think the skier is pretty safe, the shot lands 38' out the side. You'd have to be way inside 38' and right up on the boat to get hit. Since in the marketing lit they say it's GPS based, I'd guess it won't fire unless you are at ski speed so the only one who could get hit would be someone in the boat, and I would hope they have some kind of sensor to prevent that as well.

@MNshortliner, just a revolutionary new bottom shape for slalom skis LOL. I don't think I ever posted anything.

HOLY COW! I started working on something very similar about 3 years ago. I bought the paintball guns, built the control board, and wrote the arduino program, but that's as far as I got. It's been sitting on the back burner ever since. My program relied strictly on timing, no GPS so this one is better. The problem I was chewing over in my head was dealing with wind and side to side boat attitude. I'm assuming these guys have worked that out. As for the 55's, I don't know what they are doing, but my program was written to accommodate a strain gauge on the pylon, when the load goes high on the gate pull out, it fires a "zero ball" to set you up for your gate. The strain gauge also acts as a safety, if there is no load on the line, the guns won't fire. The added benefit was a "skier fall" alert to the driver when there was no load on the line after a short delay. I'm so stoked (and a bit jealous) about this, I doubt my version ever would have made it to market so having this pop up is awesome.

Very pretty! It's driving distance to me as well, but alas no room for another boat in my life.

I'm with @6balls. All the boating wisdom I know of is to take large swells on the diagonal. I've been in HUGE (6 to 10 feet) swells on Lake Ontario with 3 people in a 14' aluminum boat with a 9.9 outboard. My best friend was driving and we alternated between surfing the waves and letting them pass under us. It was a terrifying time on the water for sure.

And this one speaks directly to my point about mixing materials.

@BraceMaker and @eleeski, I think we're all on the same page. We've all worked with these materials, (admittedly I've never used boron, Holy Crap Eric!) and with careful thought and trial and error you can build something pretty good and certainly you can build a ski that will, at minimum match a top end production model but likely exceed it. (from a structural perspective) My point was, and still is, that for a novice, building their first thing ever out of composites, best results will come from sticking to one material. Or, doing a ton of research first. I think both of you guys likely have more experience than I do with composites and for me I was building my boards based on previous failures and hearsay as to which material was best where. My next structure will be very different now I have a better understanding. One video that turned my head a while ago was this, for anyone working with or thinking of working with composites, it's a pretty good watch: Chris

@eleeski, I'm not disputing the virtue of carbon, or the goal of making a good light ski. But I stand by what I said. I've built a lot of combination layups that failed when in my mind they should not have. Building something, breaking it, then reinforcing the spot that broke is just a very long tedious game of whack a mole. The problem of mixing materials is that they have different properties, and if you don't understand where and how the load will be carried, you can literally be adding weight without any benefit. I've only recently been educated on the problems of mixing materials, and I wish I had known 30 years ago. Carbon is stiff, glass is strong. That's an oversimplification, but it's a good starting point. If I put a layer of carbon, over a layer of glass, the resulting structure is only as stiff as one layer of carbon, and only as strong as one layer of glass. The carbon will take all the load (because it's stiffer than the glass) until it fails, then the load will be transferred to the glass. This is why I advocate that a novice to stick to simple layups of one material. If you want it to be stiff, use carbon, if you want it to be strong use glass. If you want both, use a lot of carbon. The other big advantage to a novice of using glass (specifically S glass) is that it is transparent. This makes dry spots in the wet out much easier to spot. It's also much cheaper.

@eleeski, I'm not disputing the advantage of using carbon or of making the ski lighter, but in this case we are talking about first attempts. I've broken a lot of boards with expensive carbon/glass/kevlar layups that I thought should not have failed. The big mistake that people (I was one of them) starting out with composites make is using a mix of carbon and glass (and worse, Kevlar) without properly understanding how the different properties of the materials behave in a finished structure. The issue is not which resin you use but where things go in the structure. If you simply lay carbon over glass, because the carbon is stiffer, the carbon takes all the load until it fails, and then the glass takes the load. So the resulting structure is only as strong as one layer of glass and as stiff as one layer of carbon. For non engineers who cannot properly understand where all the loads will be carried (I fall into this category) the best product will result from sticking with one material. If stiffness is important to you, use carbon, if strength is important, use glass, if both are important, use a lot of carbon. Personally I think people gravitate to carbon (again me too) because they think it's better than glass. It isn't, it's just different. The other reason I recommended glass (specifically S glass) is it is a very good CHEAP material. Plus, because it's transparent when whetted, it's easier for a novice to see voids where the cloth is not fully saturated.

I highly encourage you to do it. I've built all my own windsurfers since the '80s and plan to make a ski at some point. Don't expect a brand new Denali on your first try. Making your own gear is very rewarding, but it's a journey. I'm both a wood worker and a plastics (fiberglass carbon etc) guy, and my advice would be if you just want to build one without plans to build another, go wood, if you want to start building skis, watch some surfboard building videos to get a feel for how to use the materials and give it a go. Also google" how it's made" they did an episode on how modern slalom skis are made, I can't remember which factory, but don't obsess, you don't need a hydraulic press to make a ski. From that video you will get an idea of how many layers of cloth to use. If you do go composite stick with glass. Carbon is not as strong as glass, and unless you really know what you're doing, mixing carbon and glass is a pretty much guaranteed fail. Finally, try to make as accurate copy as you can of an existing ski that you have access to ski on. That way you can compare your ski to the factory ski to see how you did. Also make it heavy, if your ski weighs the same or less than the one you copied, it will almost certainly break. Good luck!

HOLY CRAP it sold for 20K! I think I'm gonna cry.

Current bid 19K. If I could have it for that I'd be mighty tempted, but I'm sure it's worth at least twice that. As for how it would track, I would imagine actually better than or at least equal to the same conventional boat with tracking fins. @skiinxs that's pretty much what I was thinking, except you would have a fixed foil where the front tracking fin is and a smaller trim-able wing behind the rudder. Then it just flies like an airplane. The other thing to consider is that we only ski in at max 6' chop, so it only barely needs to clear the surface for max effect, it doesn't need to sit high. If I had the time, I'd love to retrofit my old Supra and give it a try.

Glad to hear I'm not the only one. I windsurf as well as waterski and only certain bodies of water at certain times of year affect me, but when they do it's intolerable. I have a fantastic traditional Chinese medicine practitioner and he fixed me up pretty quick last year. I've also done the neti pot and sometimes pseudoephedrine worked sometimes not.

I have actually given this a lot of thought for a long time, and where I think for ski boats this becomes a problem (aside from the inherent issues with hydrofoils) is getting the beast on and off a trailer.

You want this because it is AWESOME. Thanks for posting, it made my morning. I've always thought that if we really wanted an awesome slalom/jump boat it would be a hydrofoil, sucks for trick though.

Duck

My last set of the season, didn't realize jmac had posted it until just now https://www.instagram.com/p/Ba0H1SwHt_e/

I have a decent grasp of the aerodynamics and hydrodynamics of the the water sports I enjoy, and yet slalom ski fins confound me. Perhaps someone who understands better than I can explain a couple of things. Why do we not use foiled fins and what's up with all the holes? The basic shape I get. It's essentially a delta wing which doesn't reach a point of stall as angle of attack increases, it just continues to loose lift. This makes sense as the fin never completely stops working, it just slides more the more it's pushed. The problem is, it's not a particularly efficient shape, and when you punch a bunch of holes in it, you make it worse. I may do this experiment my self, but I would wager that if you were to draw a line connecting the edges of all the holes, and then cut the fin along that line, it would perform nearly the same.

@Buoyhead69 now I get it, I missed that those falls were at 22, That is kinda strange. How's the wake at 22 on the boat you ski behind? In my case I'm skiing beind a 200, and I don't really notice it, but I've heard that 22 is the worst length for wakes behind most boats. Is it possible that the 22 lump and your new ski setup to is the culprit and shorter lines are ok? Just a thought.