Aftermarket Wedgelike concept

Hello all, new to the boards.
First intro:
-I am an engineer
-I can make just about anything in my shop or have it made affordably
-Used to be a pro snowboarder and fell in love with wakeboarding in 1997 competing in the boardfest competitions in CO here.



I just picked up a 1988 ski supreme for wakeboarding. Looked at other boats but for the price I could not beat it. Plus the steel stringers and positive motor mounts appealed to me. I now ride with somewhere in the neighborhood of 1000# of ballast depending on who is with us, but still experimenting. I have seen the Wedge system and it seems OK but I think there is room to improve, especially for those of us without the budget for a 70K boat.

I have been looking into a method of an adjustable wake enhancement without the excessive ballast, I know the holy grail. Searching around, I do not see a whole lot of into on any such device that would attach to an existing boat that is not so equipped already.

I am looking to make something that:
-Does not require additional drilling.
-Adds a flow directed water stream to specifically enhance both wakes.
-Is adjustable and or capable of dynamic correction for boat pitch (damped hydraulically). I do not mean as a hydraulic control...but a fixed damper with an adjustable valve.

Does anyone know of such a product currently available?

Fig

No such product exists. Also, if one of your criteria is to "not require additional drilling" I doubt any such product will ever exist. Good luck though, keep us informed on your progress!

-Steve

I would certainly be in the market for one if you were able to produce such a device. I am very handy with machining/welding and was considering designing one for myself but do not have extensive experience with fiberglass and hydrodynamics. Please keep me posted and if there is something I could do to help let me know.

Other wake enhancing devices have been made, adapted, or stolen from other applications and include the good old trim tab, both hydraulic and static versions and the switchblade.

http://www.switchbladewake.com/

Either way I wouldn't add anything to my hull...

There is a company that makes an aftermarket wedge type product. I havent heard much about them though...

http://www.switchbladewake.com/

Ya beat me to it...

I have thought about this a bit, and have always wondered if one could attach a foil to a "skeg" in the middle of the boat. this would avoid the "weird" wedge shaped wake.
maybe even make it adjustable so you could pitch one side up and one side down for surfing.
adjust the both up and skim accross the water like a bass boat.

you said you have steel stringers.
this may be the perfect boat to try on because with your design & shop skills you could reinforce everything to the stringers.
think about it, open the engine compartment crank a handle and adjust the wake.
take it one step further and use an electric cylinder and you could do it on the fly.

The other idea I had was to make a bimini that acted like a wing to force the boat down.
after talking with an aircraft E. (and a couple of beers). he came up with - 48" x 48" "wing" at 24 mph would only produce 125 #'s of downward thrust. (calculations done in his head, along with several beers, so this may be off alot...)

I would love to see this thread "take off" and read other peoples thoughts...

Mike, if you are an engineer, make one yourself, patent it, then sell them and make millions. No, but realistically you will never be able to create an aftermarket device like the wedge without drilling into your boat.

water weight is way too easy, plus you really have to be confident to strap a bolt on to your boat that can put enough pressure to rip a basketball sized hole in the hull.

Good luck though.

I'm an engineer too, and have thought long and hard on this topic. I have no experience riding a wake from one, but I personally think the Switcblade looks a lot like the holy grail. It's adjustable on the fly, has a breakaway feature for hitting submerged objects, and pivots laterally to minimally interfere with turning. The only thing it doesn't do is adjust for roll, which could be done with trim tabs. I don't think automatic pitch correction it really necessary, but it could be done with some sensors and a PCM, using the Switchblade. All this adds a lot of cost, complexity, and unreliability, of course.

I have drilled many large holes in many boats. It's not that big of a deal, and I agree with Leo that there's probably no affordable way around it anyway.

Mike, your buddy is right about the bimini - air won't do it. You'd need something the size of a sail. Water is much more dense, so you don't need such a big surface area.

This market isn't even close to big enough to make a million bucks on a single idea like that. Liability insurance will eat you up too.

Thanks for the immediate discussion,
Let me clarify when I say no additional holes drilled. What I meant to say was the utilization of holes that are already there. The transom holddowns, existing wakeplate around the rudder, and the ski deck mounting locations.

The switchblade looks similar to what I had in mind but I think there is vast room to improve. Again, I hate drilling, even more so in composites.



Water is easy to a point and there are certainly methods that make ballast filling easier. I just like the idea of space when it comes to being out on the water. And I like to design things. I picked up a english wheel to make another product and might try some models out. I have access to a 3D printer so I can proto my stuff in a bathtub. It will be like old times (6 yrs old)
Fig

Make the wake shape is easy, however making the boat handle and turn is a little harder...

Since we're in the design phase how about a retractable wedge device in the center and rear of the boat?

I think a retractable wedge in the middle of the boat would be the best design possible. This would provide the most evenly distributed weight on the boat. It would the most difficult to integrate and risky from a structural standpoint, ie damage from rocks and debris, etc.

I was actually thinking of replacing one of the Tri fins with a foil at one point. I am between a ballast replacement and a standalone wake generator using the boat as a power source.

The adjustability is the key as the boat should probably be pretty versatile. But replacing on of the Tri fins could allow for an adjustment through one of the studs. it would also have to replace the lateral stability and fit on the trailer.

I like the wedge on my bu somewhat crude and simple. However with more than 6 peeps I/we prefer the wake shape, gas usage, and handling without the wedge.

I like Trace's statements the most. You can get pretty wacky pretty quick; the most simple solution is often the best. That doesn’t mean that there isn't a killer idea out there. Have you looked at the patents that are out there already? You don’t want to invent what is already done.

We ran a Centurion Avalanche with a Switch Blade at the Scioto Wakefest this year. The riders were pretty amazed with the wake. The driver liked the on the fly control.

Q1: If you had a good idea and if was really good why not drill the holes?
A1: If the idea is marginal or maybe even bad the holes will reduce the value of my boat, right?

Q2: So how do you develop and test an idea with less risk?
A2: Analysis, simulation, and maybe scale modeling.

(Message edited by Bigshow on September 11, 2007)

this VERY crude drawing may better explain my idea.

outline is any 2 fins or skegs
green - is the pivot point, where the foil starts
black - foil / wing, one on each side of the fins
red - the adjusting rod that will change the attitude of the wing.

inside the boat make brackets that connect the stringers to where the fins mount on the hull, to reinforce. this is to support the hull due to the increased stresses from the pull of the foil.


this is the only thing that I have come up with that makes sense to me.
Yes there will be MORE underwater gear that could be damaged and it would always be there, but as wrote earlier that it could be used to provide lift also, and compensate for the increased drag.

Great, now I can go patent your idea.

have at it Ed.
I would just like to see something other than the wedge or switchblade.

I have no intention of doing so. If you did have a good idea would you post it up for the world to see Some one, any one could claim credit before you got out of your chair to do something about it.

The Wedge and the Switch Blade have huge advantages over the proposed solution.

The flow of water from the prop over the wedge (a wing) add more negative lift than passive flow of water would at the tracking fins.

The wedge diverts the flow of water (a mass flow system) from the prop up. Since a mass flow is forced up something else must go down, that's the boat. Again a huge advantage over a more passive approach.

Think of the benefits to top speed and cruise with something that could lift the hull. Hydrofoils run fast and smooth through very rough conditions. Not that this is very close to a hydrofoil but you could see some interesting potential.
If you get that and a negative lift option at slow speeds it would be neat.
Have fun with it Mike. I think you are going to run into some pretty high stresses on limited areas of the hull and you're going to have boundary layer issues with it being so close to the hull but I have never been one to avoid a challenge.

well, I will certainly be taking the simulation and scale modeling approach before I would bolt anything to the vessel. I am not trying to reinvent the wheel, but looking to bring something affordable to the older class boats. I see plenty of guys scraping up boats to get out on the water and I would love to have a simple device that not only makes the wake but allows wake shaping. This is mostly driven by balance which changes with passengers etc. So it has to have several dimensions of adjustment...not just up and down.

Fig

Mike, that is a really slick idea. Also, FYI this thread would easily hold up in court as prior knowledge if you end up needing to sue Ed.

Fig, I wish you luck. My advice is to look into product liability insurance costs first if you plan to retail it.

Drilling holes is really no big deal. I used to be the same way. Believe me, you'll be way more careful and thorough than most all dealer techs that are installing towers, PerfectPass, and pop-up cleats all day long. Also, all the existing bolt-ons are in different locations across different brands & models of boats. You would end up making a ton of totally custom designs, when you could probably get away with a much simpler product line with bolt-on mounting adapter plates.

Ed, that's a really good point about the foil being much more effective when it's located in the prop wash. Never really thought about that. It also addresses the boundary layer problem that Art mentioned.

I'm not fresh enough on fluids to know the boundary layer thickness in these conditions off the top of my head, but my gut tells me it's not very much in something as dense as water, at wakeboard speeds.

Trace, if I have a signed and witnessed note book with the same idea one day in advance of Fig's idea he has nothing.

(Message edited by Bigshow on September 12, 2007)

I have fiddled with this concept, put a wedge on a MasterCraft PS190 many years ago.

I had to do quite a few tweaks on angles, notch the rudder etc, but it did work fairly well. The initial test run nearly sank the boat, looked like the Titanic, nearly swamped the back of the boat with a full throttle top speed of about 10 mph.

I also did some patent searches regarding mid ship hydrofoils similar to your thoughts and someone has patented that concept. If the patent has not been maintained, it may be public domain now if you are looking to produce a similar device. I like the idea and I think it is worth testing. You can always repair the fiberglass or other areas of the boat if it does not work out.
Good luck and keep us informed if you get something on the boat.

I had a friend run drag simulation for the 250HP power source and the general speed of 22-24MPH and the max dispersion angle is 30 degrees at most before it stalls out and the fluid breaks up completely. More to come.

One side note is that the price tag of $2500 for the switchblade is close to what I paid for my boat. I am too cheap for that noise. Espcially with a control system that is super hokey...did you see the video...the speed of the guys hands when he wants it to stop...way too sensitive.


Fig

I too am going for engineering and would guess the best way, although drilling would happen, but attach it to the metal brackets of the swim platform... then if you screw up you're out 30 bucks for a new bracket, not hundreds... i would think two support arms, one from each bracket would hold... if you do this, I want half the $$

Good stuff guys.

Mike Murphy (co-designer & patent holder of the AirChair/SkySki hydrofoils & Pure'Vert ballast system) has been toying with designs like this for years. He had one installed on a late 80s MC 190 & tested it in the Long Beach Marine stadium a few years ago. It was basically an adjustable foil in the middle of the boat & simulated quite a bit of weight. They had multiple issues to work out on it but it seemed very feasible. As I recall one of the issues was the pre-existing patents on the concept. Murphy is good at this patent stuff too, so if it can be done, he'll find a way to make it happen.

FYI, SB has a new controller and revised geometry for '08. The controller has 6 pre-set positions, and will automatically deploy and retract. This system will debut at Surf Expo. The website will be updated in the next month or so. Look for some other interesting offerings from them in the near future.

(Message edited by siuski on September 12, 2007)

That twitchiness in the controls is pretty common to trim tabs. Glad to hear they have it fixed.

nick T
I like your idea about using the swim platform brackets, but have some questions.
#1 how much force would you try generate? I ask because no more than 2 people can be on MY platfrom at the same time. sitting, standing what ever. no more than 2, ever. yes I am a "new" boat owner, and I worry too much. so that means I would not put more than 225 #'s of downward force.
#2 how would you support the foil from NOT bending back?
Could this be like the free floating wedge? I am not sure how that works....
If this is a valid question could someone explain the freefloating wedge?
#3 if not a foil what about a water tank, below the swim platform. I know that several years ago this was used on an off brand boat (extreme, or gekko, or something like that). I was wondering why it had died? I liked the idea that it was out of the boat, and it a standstill all the water weight was nuetrally bouyant. so when your riding you have a great wake, when you get stopped for being over weight, your fine! it only work against the boat when the boat is on plane (the swim platform/tank is out of the water).

The swim platform just provides and easy place to bolt through the transom without the drilling of new holes. The leverage on the ski platform with the mounting bracket length makes the platform weak relatively speaking, but the through holes are still good. Just because tech drill through the transom to add a speedo line or similar does not mean it is the same as installing a structural element. The ski deck was designed into the boat and I have not checked to see if its reinforced, but it should be. Worse case you end up making it better with a backing plate. I am glad the controls have changed for the SB, that was obviously customer feedback driven and 5 stages are probably enough. I think I am going to take a slightly different approach from other ideas here for the first round we will see how it goes. I am thinking more on the lines of extension...



Fig

That looks like a horrible copy of the wedge with none of the fluid dynamics. It is probably still effective...but at a high cost of drag.

Fig