aftermarket wedge system [Archive]

stinky_1

02-13-2011, 07:55 PM

so, I had been doing research on something like this for my Nautique. I did come across this

http://www.wakeworld.com/MB/Discus/messages/65921/85761.html?1075167217

I learned a few things by digging through that thread

1) You need to make sure anyone driving the boat with the wedge down knows that you can NOT power turn at any speed. This is how stuff like the wedge ripping off happens.

2) If you look at the pics in the other post I linked to, you will see that the hull is NOT reinforced where the wedge is attached. At first I figured it would be a LOT thicker than that. After a while of looking, and figuring I realized something. The forces on this will be pulling pretty much straight down. They claim about 1000 lbs of ballast, which would mean around 1000 lbs of force on the hull. We are looking at sheering strength, not straight pull force. I would throw a metal plate across the back as big as I can actually do. but otherwise you should not need anything special.

3) the pics of the home made wedge clearly show that it was welded to the supports. If something had to "give" I would think it wil be your hull. I would go for the bolted on design. This allows for a engineered "sheer pin" basically. So if something were to happen you would hopefully rip the bolts out of the wdge part, and keep your hull in tact.

4) this should be a really good solution especially for the guys with low freebord. The weight increase is only felt when you are moving forward. SO while sitting in the water you boat will be at factory hight. Which is good. No worries about big waves crashing over the sides. Once you get under way the wedge will pull your boat down and make the wake you want.

The actual system looks pretty basic. There is not a lot to that at all!

As near as I can tell there are only a few important things to note. First of all would be that the wedge needs to angle slightly down from the angle of the hull. It will want to ride parallel in the water, so once it is horizontal, your hull will have a bit of a rise to it. If you dont get that angle right you will not create the same down force as you would like. A real precise guy would try to measure it somehow relative to the hull. If this was me I would go for trial and error. Take some shims with you and you can always angle the wedge part more or less by a few degrees once at the water.

The only other thing would be to go for overkill on the hull support. The more support you can add the better off you are.

The rest is unimportant.

Let us know how it goes. I still have not written off the idea. And I am confident it would work pretty easy.

stinky_1

02-13-2011, 08:54 PM

so, after very little pushing or prodding I have decided I am going to make one of these. I am not sure when I will actually bolt it onto my boat though. If anyone has access to a real one I would love some measurements. Otherwise I will just go off the pics and come up with some rough sizes.

I have all the stainless I should need to create this. And the hardware will be pretty simple.

I will try to take some pics of the creation process as well.

The expected start date for this is still 4 weeks away. I need to wait until I am working afternoon shifts at work again. That way I can be left alone to create it.

jet

02-13-2011, 10:22 PM

Stinky you are correct..the force is pulling downward and the foil only has a degree or two from horizontal. My unknow question is how the boat sits when its in the water?? So you might have to compensate for that tilt to the rear. I will bet that my old hull is smaller and thicker than most newer boats in that area, but a large backing plate is what I was thinking to. Just go ahead and make 2 of them..PLEASE!!!:mrgreen:

mapleleaf

02-13-2011, 11:00 PM

ya or 3, I've had my gas tank out enough now too pull it for a backing plate install..or that glass work I know I'll be doing.
Stinky, we're working on a summer Alberta trip, I'll let you know when I'm coming to pick it up!!!

stinky_1

02-13-2011, 11:02 PM

Ill get the first one made, then see how that works as a prototype.

I have looked at those pics and its looking like they set it up to be about 5 degrees off the hull or so. Ill show you guys what I come up with. That one in the link should be easy enough to mimick.

jet

02-13-2011, 11:10 PM

stinky..I was thinking 2-locking positions. light and heavy?? my buddy has a Bu so if we need any measurements let me know. Im thinking the wedge..600 in the rear and 400 in the front? OH..YEAH!!

mapleleaf

02-13-2011, 11:20 PM

we can call it.... Su Wedge.....lol

stinky_1

02-14-2011, 12:02 AM

the locking positions will be easy enough to have more than one, I will see what I can find for materials and go from there. We deal in stainless all the time at work (food industry) so we should have enough scraps lying around to get something together.

if I am making more than one I will need to get some sort of price on materials though and charge a minimal fee. I know I can scrounge enough for one, but 3 or 4 will get harder.

mapleleaf

02-14-2011, 12:15 AM

Hey Stinky, if you're not kidding, I'm totally down. I didn't have too many plans for ballast this year beyond a better pump for the bags I already have and they're big and cumbersome. The metal shop around the corner owes me a few favours so I thought I"d see what kind of measurements we could come up with and go that route, but I'm not in a huge rush. If you've got some ideas, I open to them......Let me be the first to thankyou for choosing Supra!!!!

stinky_1

02-14-2011, 12:24 AM

no need for thanks, I havent done anything yet. I was honsetly looking at this very seriously to put on my nautique. The only reason I gave up on that project was because I was planning to sell the boat.

I love the idea of having a pin to pull and instantly have 1000 ish lbs of ballast. The system itself looks pretty simple. I am not even sure that there is that much engineering that is involved. Meaning, you can get "close" and still get results.

I understand what the water should be doing, and what the boat will be doing, and how to achieve that. I just may not have it fine tuned.

I am thinking I can setup a sort of trim plate similar to the old manual out board motors ran. They had 4 or so locking positions, and could get a LOT of different angles based on that.

Maple, let me know when you figure you will be out this way. We can try and hook up for sure. if nothing else you can see what the wedge looks like in person. and we can go show you how well it works (or doesnt.)
I will have my father in laws boat out here too (85 sunsport) so we can compare hulls, and wakes and all that fun stuff.

jet

02-14-2011, 11:57 AM

I am down to Stinky..dont mind paying at all. But FREE would have been nice. lol. I was just thinking of a name for it too! lol. How bout the machete or the shank! LMAO

87SunSportMikeyD

02-14-2011, 12:39 PM

Awesome, I will be following!

Fman

02-14-2011, 12:52 PM

Not trying to hijack your thread, but the new AXIS boats are using a similar wedge setup... attached is a picture and a description of how it works.

"Looking for another 1000 pounds of displacement? Add the exclusive Axis Auto Set Wedge and you can bring your wake footprint to nearly 3200 pounds of displacement on top of the Axis boats’ other available ballast. The Auto Set Wedge can be deployed through an access hatch in the standard fiberglass swim step. A simple pinch of the clips and the Auto Set Wedge is ready for wake-making. This reverse hydro-foil floats to the perfect displacement position and turns up the volume on your wake size. No ballast. No filling, No draining, Just wake."

Might be something to consider, possibly could purchase from Malibu.

jet

02-14-2011, 01:08 PM

Fman..Quit making me drool with that pic. You dont want to know how much they cost$$. Used ones sell in one day for $500-$800 on ebay but they sure are pretty!!

stinky_1

02-14-2011, 09:43 PM

I have watched the vids for axis wake boats many many times. Even saw Adam at the boat show in calgary a couple weeks ago. I checked out the wedge there and had some close looks it it all.

Thing thing I am stuck on for those is how the "auto" or "floating" part works. It seems that it should naturally find the best position for it to pull the boat down. And I may end up trying mine without the pin in and see what it does. But I also like the idea of locking it in place and having it be exactly where I think it should be.

And yes, a used one will cost a pretty penny. You would know it will work, but I think I can get pretty close to that without much trouble.

Watch for the pics in about 3 weeks. Ill try to document how the process goes.

jet

02-15-2011, 12:36 PM

The floating wedge scares me a little more and Im not sure I understand why that works better. locked down its at 100% effective at that angle right? And if floating, that would allow the water (or force) to push it to a postion where it wouldnt be as effective?? Also the scary part would be if the wedge is at a 3 or 4:00 position that would be more outward stress put on the back end of the boat rather than in a 5-5:30 position pulling in the downward position..right??

stinky_1

02-15-2011, 02:42 PM

I had some theories on it, but dont know for sure. Ill see if I can explain it later when I am not at work and have more time.

chrisk

02-15-2011, 04:15 PM

Yeah this is a very interesting/scary topic. I'd love the idea of not filling my boat with ballast EVERY time I go out, but those pics on wakeworld scare the crap out of me.

I'll be watching Stinky! Maybe you'll have another customer

stinky_1

02-15-2011, 06:32 PM

so, I think that the word "floating" is a bit miss leading. When they say that I used to picture it floating at the water line somewhere. But I no longer believe that is the case. I think floating simply means that it is not fixed into position.

If the blade is shaped correctly it should have a tendency to pull straight down relative to the water (not the hull). This would be critical for doing activities that require the hull to be at different angles. For example, your bow will be much higher in the air while surfing than wakeboarding. So, if you have the blade fixed at a certain angle it will ONLY work right for one of those 2 activities, but not both. The reason being that while the bow is up in the air, your blade will be trying to push the bow back down, not pull the rear end into the water.

if you were able to have that blade "float" and auto correct its angle so it always has maximum down force, then you can surf or wakeboard without having to mess with the plate.

I do not believe that the plate will be straight back and pulling straight out on your hull. I think as it is slicing through the water its tendancy will be for it to come forward, and as the boat pulls away from it you end up in the neutral position which should be some where around maximum angle for the thing to work.

the question then comes up, is this simply a regular wedge that has not had the pin put in? I looked at the pre floating wedge as well as the floating one. I cant see any significant difference in it. So, I would be willing to try it with the pin out and see what happens. Obviously I would do it from a very very slow start speed and have my platform off so I could see what it was up to.

Either way, If I have enough locating holes in the bracket I should be able to make it work for both surfing and wakeboarding. But you should not be able to have it in the same position to get he best wake on both normally.

Hopefully that sort of makes sense, and not just a crazy guys ramblings.

chrisk

02-15-2011, 06:57 PM

I understand what you're saying, however I don't think the physics of it makes sense at all. I just can't picture the wedge, basically on a hinge, staying in optimal position. The whole theory about auto-correcting doesn't make sense because the blade doesn't know what angle we want as wakeboarders, it doesn't know that we want it to be creating downforce. It will "think" that the optimal angle for it, a piece of steel moving forward through water, will be completely flat with barely any resistance and equal pressure on both the bottom and top. What creates the downforce, is us wakeboarders predetermining what the angle of the blade will be when our boat is moving, thus creating the higher pressure on top and the lower pressure on the bottom. It's just like if you were building an airplane, you wouldn't put the wings on a swivel and trust that they're going to find the optimal angle for YOUR flying. I think there must be more to the "floating" wedge than just letting it do its thing.

stinky_1

02-15-2011, 07:07 PM

I know where you are going, and its something I still struggle with. This is why I am going for the fixed position with a pin holding it in place.

I dont think there is much to get "wrong" on a fixed one. As long as it has a bit of backwards lean to it, it will be pulling the boat down.

I am guessing there was a bit more engineering involved when they made their floating wedge.

Also, the airplane is close for an analogy, but you need to realize that we use the wings to steer the airplane. On the boat we can adjust the bow height based on the throttle position. The "wing" in this case is passive and will do whatever it does to get through that water with the least amount of resistance. if it was beveled correctly you would make it naturally ride lower or higher in the water.

On the airplane we are using the wing to do ALL of the lift as well as steer. In the boat we just want it to pull the back into the water. So I am not even certain that the entire picture can be looked at from the same angle.

please dont get me wrong, I am not trying to say you are wrong and I am right. I have no idea if I am right. I dont see any other means to force the wedge into position when I looked. So I have to try and bend my reality to match what I think that wedge "should" be doing to do what I think it should.

Anyone else with insight is more than welcome to jump in here as well

stinky_1

02-15-2011, 07:14 PM

here is a quick youtube vid showing the "manual auto wedge".

http://www.youtube.com/watch?v=QF54YdmOuIA&feature=player_embedded

The manual part just means you have to still go to the rear and pull the pin. then it does the rest.

jet

02-15-2011, 07:34 PM

Thats what I was trying to say, but didnt have the degree (self taught) to back it up! lol. I am also self taught in the sex department and look at me now. Ima ladez man! LMAO. Here you can see the 3-5 degree?? angle of the wedge in the water. Its a cool view. Wish they would have kept it there longer.

stinky_1

02-15-2011, 07:45 PM

pssst Jet, there is a pause button on the left bottom corner of the vid. You can push that and hold the wedge in that position forever if you wish:D

I wish I could see it from different angles. They play a bit with your mind on this one. The angle of the bracket swoops back away from the boat, but the wedge itself is only sitting a few degrees off from the angle of the boat. Its just attached at an angle on the brackets to do that. And maybe that is how they make the thing pull itself down in the water?

In fact, I bet that "is" how its happening. Its not pulling straight back, it will pull to the leading edge of the support, which will make it want to come forward on it. Which is why it ends up being flat in the water no matter how the boat hull is?

Guess I will have to play with that idea in the design. If it doesnt work I can always pin it into position still anyway. So it wont change much. I wanted it to stick out a bit anyway, so having the support angle back like that will help me.

angus2112

02-15-2011, 10:13 PM

i am also working on this putting stringers my comp and going to redo the transom to handle the wedge check this link out
https://picasaweb.google.com/myfourday/MalibuCustomFloatingWedgeFor87#

mapleleaf

02-15-2011, 10:25 PM

Jet linked this at the beginning of the thread, Is it your brother that made that one? If so, it looks amazing! How has it worked????

stinky_1

02-16-2011, 01:38 AM

i am also working on this putting stringers my comp and going to redo the transom to handle the wedge check this link out
https://picasaweb.google.com/myfourday/MalibuCustomFloatingWedgeFor87#

I was going to say that this looks like its actually floating. But then I noticed the album name which says that it is.

I like it. There should be enough pics there for me to replicate that.

stinky_1

02-16-2011, 01:41 AM

I cant quite tell what the micro switch was for though. I am guessing they set it up so it triggers that light on the dash when it is all the way on the rest stops? So this way they know if it is auto setting

96Comp

02-16-2011, 11:54 AM

Since I plan on owning my Comp a long time, I thought about the Switchblade system. Here are the results of my research -- called Supra and discussed the idea. Their first response was "will definately void your hull warranty." Given other posts about the warranty, not sure this was much of a deterrent. Finally got a call back from an engineer who was not invovled in the Comp design, but was familiar with Malibu (built down the road in TN). I think these guys go back and forth between companies -- or at least discuss over a beer! Anyway, the stern design of the wedge boat is completely different from direct or v-drive. Remember Newton's law? For every action, there is an equal but opposite reaction? Direct and v-drive absorb the force of moving the boat through the water in the floor and stringers, not the stern. Wedge boats also do that IN ADDITION to the the force of the wedge, which from the stern's perspective is UP not down. The pics in the wakeworld link are accurate: If the stern fails (whether because wedge struck an object or hydrodynamic forces) the stern shears from the bottom up. Wedge sterns are reinforced across the entire floor and stern, up to the cap. The Supra engineer also recommended I call Jim at Viper Customs, because he was involved in Comp design back in the day. While at Viper in November, I asked Jim. Short version is he definately recommended against the wedge for all of the reasons mentioned above and a new one: The wedge also places extreme forces on the rudder and rudder box. So even if you were to reinforce the stern and somehow make an effective engineering bond to the hull, you also have to reinforce the rudder box. For me, I am not going to do this. What are the options? I guess just the ballast bags. I had Fly-High make a custom bag for me shaped in an "C" so it lies beside and behind the motor box, sort of like the rear seat bag they sell, except smaller. I have one bag to fill. It's a tough bag and people step on it. If I find I need more wake, I will buy a bigger boat -- or better get a friend to buy a bigger boat and let me use it!!!

jet

02-16-2011, 01:57 PM

OK guys..lets throw this around?? Im redoing my floor right now so I can rebuild mine how ever strong but, Comp has a good point. How bout making it lite enough to break away..maybe not use SS? Jet

stinky_1

02-16-2011, 03:03 PM

I was hung up on the strength of the hull for a long time. it wasnt until I saw that other thread with all the holes in the hulls that I changed my mind. You can clearly see that there is nothing for reenforcement on the hull in the back. Unless they have some fancy carbon fiber something in there? Because it certainly isnt any thicker.

I am wondering if all these "expert" opinions are based on them thinking it wont be good, or knowing through their own strength tests that it just can not hold up. I have a tendancy to want to over engineer everything. And I wonder if they suffer from the same problem?

Then I see posts of other people who have made their own, and what they use to reenforce the hull. How come theirs is holding up fine?

Also, the older malibus that never had a wedge can buy and install it with no problems. Malibu strengthened the hull in the 80's just in case one day someone would want to add a wedge that they have not invented yet? Something just seems odd.

I think that there is certainly risks with doing anything of this nature. And anyone who is doing it should be aware of those risks. But I dont think every single person that throws a wedge on their boat will have the hull ripped in half from it.

stinky_1

02-16-2011, 11:49 PM

once I get my boat here I will have a look at the stringer system a bit. If I can get that bracket to tie into the stringers like in this pic below I think we will be more than good

https://lh5.googleusercontent.com/_BRj3mc8Ycgw/S_sIomEnxDI/AAAAAAAABDw/eRiLGM2q0n0/s640/photo.jpg

I just have to see how the tank fits in there, and all the space around it. This may take a little bit of doing to make sure it fits into the supra hull. But otherwise I dont think this will be a problem.

I am not worried about blowing a hole in my hull. If I do, I can remove the wedge and patch it back up and forget anything happened. The boat will for sure float again without much work.

stinky_1

02-16-2011, 11:50 PM

One thing is for sure though, whoever built that thing is an amazing welder. Mine will NOT look as good as that. I can assure you all that.

jet

02-17-2011, 02:23 AM

yeah. I noticed it to. Very nice. Jet

angus2112

02-17-2011, 09:59 AM

i made my stringers out of lvl ( lam beams). i am taking another piece of lvl all the way across the back of the boat. it will be setting on top of the stringers
so it will not take away from the room for the fuel tank.
help me under stand why the wedge will stress the rudder box are you talking about the upward force on it .

jet i do not know the guy that built that and i could not open the link

stinky_1

02-17-2011, 10:55 AM

I couldn't open jets second link either. I am glad you re-linked it.

I too am curious about the rudder statement. Also the upward force on the hull as opposed to the downward force. It's a bit misleadIng. The upward fOrce comes from the water wanting to push the bottom of the boat I
Up in the water. There is still a downward force on the transom where the wedge is attached to it. This upwardforce is 100% equal to he upward force on the hull with the same amount of ballast in it. We are not adding Amy extra tress to the bottom of the hull than these guys running 3000 lbs in their sunsports all ready

I agree there is more down force on the transom where the wedge is fixed though

stinky_1

02-17-2011, 10:57 AM

Last post made frOm my phone. Sorry it's messed up

jet

02-17-2011, 02:42 PM

oh, sorry. Didnt know you hadnt seen the 2nd link. I do think there is any xtra stress on the rudder and if there is it should handle it.

96Comp

02-18-2011, 02:12 PM

What makes a bigger wake? Hull design, displacement, speed -- to name a few. What the wedge does is add "displacement" to the boat without adding physical weight. Otherwise, you add displacement by filling fat sacs. The wedge displacement essentially is hydraulic, i.e. the wedge and the water. What I meant by the force is "up" is that the force where the wedge supports contact the hull is actually up, while the wedge pulls the boat down. What Jim at Viper said about the rudder is that the wedge actually inhibits boat movement because it resists - to some degree - the hull movement caused by rudder changes. However, you still want to turn, so you add more rudder to get the boat to turn in an amount that used to be less without the wedge. Perhaps this force is small relative to the displacement force, but it's all force nonetheless -- Force for which the hull was not desgined. Someone commented that filling with fat sacs strains as much. Maybe. You can cause the hull to fail if you exceed capacities ... ah, hum, Jet ... but even with a lot of fat sacs, the weight of the fat sacs is distributed across a larger section of the floor and hull, not centered on the stern. My other thought is that there are a lot of ski tow boats out there that throw a decent wake when properly displaced (loaded). The real pain is all the bags in the floor. The same is true for larger "real" wake boats, except their hull was desgined for a larger wake, aka deeper free board, "V", etc. If you could have a ski boat that would not be cluttered with bags, I would think that many folks would have these wedges. Honestly, I have never seen even one, except on a Malibu. More on that. One would also think that Supra would make the wake boats with wedges, and not have to put up with the fuss of water sacs, plumbing, leaking, etc. to add displacement. I mean, forget the sac issues and the lockers they fill, even on the big boats, just drop the wedge and instant wake! I don't see that happening either, but admitedly I am not in the market for a new boat. Back to the Malibu. I noticed one last summer at a boat yard near our lake. Don't know the model, but this boat is sharp. I was out there Tuesday on business and saw the boat again, apparently having sat outside all winter. I saw it had the wedge system. So, I stopped to see what's up. When I looked closely, the hull was cracked from the wedge up through the right corner about mid-way down at a 25 degree angle or so. One of the mechanics came out, so I asked about the boat. He didn't know what happened, but that the owner was in dispute with Malibu. I would hate for that to happen to mine, so I will stick with fat sacs.

stinky_1

02-18-2011, 02:29 PM

first of all, the reason no one else is running a wedge is because of patents. Malibu invented the thing and patented it. Anyone else who wants to put one on needs to license the rights from malibu.

Nautique has a similar system with their hydro gate, and supra has their trim tabs that are power run.

They all run some sort of ballast enhancer in the hull, just not the same.

I can see the point about the rudder. You will deff need more steering angle to turn the boat with the wedge down. not because of the weight its adding, more because it wants to keep the boat level. So most of your stress will be on the wedge itself, not the rudder. This is also how 99% of wedge failers happen on factory boats. We always say not to do power turns, malibu owners just end up learning that lesson the hard way.

I completly disasgree that the force on the actual plate where the wegde mounts to the hull is pulling up. I would need to see a picture before you could explain that one to me. It is pulling down, no other way to look at that. The place that the upward motion happens is the waters tendancy to want to push the entire hull up. I am talking about the bottom of the boat, not the back of it. This is the exact same amnount of force as an equal amount of ballast weight would generate. I will certainly agree that there is added force on the rear of the transom, and it is possibly more than the boat was ever designed to handle. But I will not concede to the idea that the wedge is some how pulling UP on the back of the transom. Its just not happening.

If you dont beleive me, try going outside, jump on your rain gutters and hang there by your fingertips. Let me know which way the gutter comes off the house. By your theory the gutter should lift up into the air rather than come down. I am going to assure you that they will come down with you. The wedge is hanging on to the back of your boat under the same principle. If it was different we would not be able to pull the boat down into the water, we would be lifting it out instead. Since the shift of force from down to up would have to happen somewhere in the wedge support arm. Which is not the case.

Hopefully that helps. I can try drawing some pictures and scanning them in if that helps.

96Comp

02-18-2011, 04:39 PM

Kinda sorry I got in on this one. Did not mean to stomp on anyones ideas. Trust me, I wanted the Switchblade wedge system real bad and was willing to part with the Benjamins! How did I come up with the "Up" theory -- well, I did not. Switchblade did when I called them to find installers and get more information in case I wanted to try this myself. Perhaps more of a twist than up, but think of it this way: (1) Take a board about 14" long; (2) Hang off the back of your boat and hold it under water similar to the wedge blade; (3) In addition to pulling you down, as the boat moves forward the water flow will pull your arms up as your arms and board resists the water flowing over the "wedge." Yes, a board is wider than the metal blade, but there is force generated on two planes. The drag of the blade, pulling the boat down into the water and the twist or whatever resisting the flow as the boat moves forward. Your arms are like the mounts on the stern. At least that is how Switchblade Co. explained it to me. They recommended one of their installers. My Supra mechanic won't touch it, but he is picky. OK -- my last post on this topic. Out here.

DAFF

02-19-2011, 01:50 AM

I can see how this would create structural and integrity issues in the gel coat and stringers. But with proper planning and design anything can be achieved. Myself, I like the idea and thought of two outer foils. This would help eliminate some of the flex and also create a right side or leI ft side wedge for better fine tuning of wake curls. Thus having a right and left side foil.... not just one in the centre. Would the cleaner water also help create negative pull on the rear of the boat too??

How does the depth of the foil relate in positive displacement???

stinky_1

02-19-2011, 01:32 PM

96comp,

no need to be sorry you joined the conversation. I do not know everything about these things. I am trying to understand what is going on just like a lot of us.

If I use your wood off the back of the boat analogy, I have no problems. And I do agree you are getting force on 2 planes. I think the direction of the force is where we differ.

Your saying that the bracket is getting an upward force on it with the wedge. So, go with your wood analogy. Your body is the bracket, your arms are the supports, and the wood is the wedge. IF we had upward force on the wedge I would expect my arms should be lifted up out of the water. The fact that I am sure I would be pulled down and OFF the boat, I will say that the force is going a different direction than up.

If you look at the pic I attached, you can see how I would say the force is going. The most force I say is pulling down. If it was any other direction it would not be useful at all. There is a small bit of backwards force as well. And even this part I am not certain of. The fact that the auto wedge comes down and forward makes me think the secondary force is actually forward moving (oposite of the hull movement). I dont think that is important at this point though. This creates the net posative force to be either slightly backwards and mostly downwards. (or slightly forward and mostly downwards).

The "opposite" force that newton says must be equal and opposite is shown by the arrows pointing at the hull. If I am pulling the boat INTO the water with 1000 lbs of force, then the WATER must be pushing the boat OUT of it with 1000 lbs of force. this means that the rear of the boat (the transom) has 1000 lbs of down force. Hence the bracket on the back is moving that 1000 lbs into whatever method we use to secure it to the boat right into the boat. The upwards force on the boat is acting on the bottom of the hull.

Hopefully that makes sense. And if anyone has problems with hos my arrows are on the picture please let me know, and explain why they should be a different direction.

Please also note that a lot of this theory comes from the fact that the wedge obviously works. So we need to explain how that happens. The auto wedge also must come down to pull down on the boat, otherwise it wouldn't work, and it would be fixed. So its final resting place MUST be pretty close to the position shown in the water. Otherwise it just would not work. There is no way we can create 1000 lbs of "equivalent ballast" unless we have 1000 lbs of down force. Force in any other direction would NOT be the same as 1000 lbs of ballast.

http://i118.photobucket.com/albums/o83/stinky_11/Wedgeforces.jpg

stinky_1

02-19-2011, 01:37 PM

so, without doing the math to be certain, here are some theoretical numbers.

Force on A = 1000 lbs
Force on B = 500 LBS
Force on C = 1500 lbs
Force on D = 1000 - 1500 lbs

The actual downward force pulling the boat into the water is 1000 lbs

The actual force felt on the mounting plate to the transom is 1500 lbs

The actual force pushing the boat back out of the water is 1500 lbs

The directions of each force is indicated by the arrow direction.

I dont show the "extra" force on the rudder here because I am not certain it needs to be accounted for. Yes, it may take more force to turn the boat, and that force will be pushing right on the rudder. I wont dispute that. But, I do not think that Malibu is making their rudders out of anything "special" to counter these forces. If you drive the boat dumb with the wedge down (ie power turning at speed) then you will break something. Either your hull, your wedge, or your rudder. Malibu has this same problem.

Salty87

02-19-2011, 04:00 PM

the design and installation of the foil will determine the exact forces and their directions.

think of an air chair, the foil is fixed but the rider can change the angle. the example of holding a piece of wood is probably more applicable here.

i guess the challenge is to design it so you get enough downward force but not more than the weakest link in the installation/hull.

complicating things is how the hull changes angle out of the hole - getting on plane...and obviously making turns.

you guys are really pushing the envelope with this one...cool!

ps stinky...nice diagram!

stinky_1

02-20-2011, 11:15 AM

complicating things is how the hull changes angle out of the hole - getting on plane...and obviously making turns.

I believe this is the main reason why they (Malibu) switched to the "floating" wedge. No matter what position the hull is relative to the water the wedge will naturally go to the point where down force is maximum. This is entirely due to wedge design and the hydrodynamics involved in it slicing through the water.

At slower surfing speeds the angle of wedge relative to the hull will be much greater than at wakeboarding speeds. This is because we need the bottom of the wedge to always only be 1 - 3 degrees off the horizontal plane of the surface of the water. at surfing speeds the hull bottom is more like 15+ degrees off horizontal in the opposite direction. So the relative angle of the hull to wedge would be around 17+ degrees (wedge angle PLUS hull angle).

At wakeboarding speeds the hull is more like 3 - 5 degrees off the water, and the wedge should still only be 1 - 3 in the other direction. Making our total relative angle around 8 degrees or less.

This is why having a fixed position is less desirable if we can help it. It allows the wedge to change to our needs on its own, no matter what we are doing.

stinky_1

02-20-2011, 11:40 AM

Also, turning can not be hellped. The wedge wants to keep the boat level. There is no way that I can see to change that. We need to just realize it and turn slower all the time. This means NOT driving to "the spot" with the wedge down, and only deploying it when we plan to be pulling someone. If you are turning properly while pulling, and picking up a downed rider you will never have a problem.

jet

02-21-2011, 01:06 PM

Remember..we will not be surfing on our boats?? Stinky, Ive been away for a while..hows it going?? Jet

stinky_1

02-21-2011, 01:22 PM

I have a sunsport, I dont expect to have a problem surfing.

The wedge may be the ticket to get your poor comp setup for surfing. It allows you to have an extra 1000 lbs of weight in the boat, but only while you are driving. So you can just about sink it with ballast, and then add the extra 1000 lbs when you are under way.

I also saw this which gives me a lot more hope that this will be just fine.

http://i118.photobucket.com/albums/o83/stinky_11/DSCF6981.jpg

it came from here

https://forum.supraboats.com/showthread.php?t=7369&highlight=switch+blade

If you look at how far out that thing hangs, and understand how leverage works, then I think this will put a lot more stress on the transom than my wedge plan which sits flat on it.

Any thoughts?

mapleleaf

02-21-2011, 01:30 PM

Seems like the wedge is over built compared to the switch blade. I like the way it has a pivot to follow the turns....
It does hang out quite a bit....

stinky_1

02-21-2011, 01:39 PM

I have not looked much into the switch blade. I only saw it for the first time yesterday when I was looking for something else.

I think the pivot is actually how it turns "on" and "off". See that hydrolic actuator on it? If you were to turn the system 90 degrees it would effectively stop functioning.

It would roll with the boat even in the locked on position because of the curve of the blade portion. Which is nice. But, there is much less area on the flat plane to generate the down force we want. So, the amount of ballast it creates I would expect to be less than the wedge.

I have seen a hybrid of the wedge ad switch blade before. It didnt hang out as far, and was fixed in the down position. But it would solve most of the turning problems. I just dont know if I want to go through the hassle of fixing one on there for minimal gains in ballast weight.

The wedge is worth it for an extra 1000 lbs.

jet

02-21-2011, 01:40 PM

WOW! That is fricken cool. But man that looks like ALOT of stress back there. Stinky..call him if you need to. I know Its a old thread but he should still have the same #?

the switchblade has like a $1000 price tag..$$

jet

02-27-2011, 10:15 AM

OK, got my tank out and was looking at the back end. Doesnt look like there is a FLAT spot to put a BIG backing plate on like I was thinking?? I guess I can remove the blower parts if we need to. Any thoughts yet stinky? I need to start thinking about reinforcing the floor back there. I was thinking about putting a big 4"x4" on each side or something like that. Jet

stinky_1

02-27-2011, 10:41 AM

I am planning to go get my boat next weekend. If I can get that to my Place then I can get started with measurements and such. Having a flat surface is ideal but not the end of the world. Give me a couple weeks and I'll see what I can come up with.

Any chance the sunsport is different back there?

jet

02-27-2011, 11:20 AM

Yeah a couple of bends here and there. I bet the sunsport will have a lot more room and lil flatter. What are planning to do to yours..anything? Resto??

stinky_1

02-27-2011, 03:29 PM

this first year I plan to do mechanical maintenance and enjoy the boat. I may try to buff the hull up. I just want it to be reliable and work.

After this season I will see if I need to do the stringers, or just replace the floor and carpet.

I will be yanking the tank out though and seeing about mounting that wedge on the back.

I am also looking for a tower since those are a definite must have item

jet

03-04-2011, 11:24 AM

I feel like a kid at Christmas again.:D:D:D:D

stinky_1

03-15-2011, 02:34 AM

so I have a bunch of the material I need now. and am getting started on the bottom part of the wedge

There are a few things I need to get from someone first.

The piece of 1/4 stainless I found is only about 22" long. I am thinking the real wedge is closer to 24". If anyone has any idea how long it really is, please let me know. (edit: Its 21.5" wide)

I still have not picked up my boat, so I cant do any specific measurements for the sunsport. I need to know how far the stock platform sticks out from the transom to the rear lip. I am guessing about 16", but an exact measurement would be nice.

The other thing I need to know is the distance from the bottom of the swim platform to the bottom of the hull.

Once I have these measurements I can get the legs all figured out and do that side of things. The mounting bracket will have to wait till I have the boat in my possession and can actually get the rest figured out with it

jet

03-15-2011, 10:52 AM

Im on it. Here is some close up pic's and Im getting measured right now.

http://forums.wakeboarder.com/viewtopic.php?t=88669

stinky_1

03-15-2011, 11:11 AM

sounds good. Once I get those measurements I will get the legs and wedge side finished. Then its just down to getting the mounting bracket figured out. I want to wait till I have my boat here though so I can see how exactly I want to do it.

I was thinking about how that wedge surface will be shorter than I wanted. This means I wont have maximum down force, but it may become a safety feature. This way I wont be able to rip the back of my boat apart. :rolleyes:

Ill make sure to take pics and write down measurements. At the end of the day I dont know how many of these I will be able to reproduce. I have enough material to make one, but not enough to make more. Once I know how much I have used I can get a material sheet made out, and get some rough costs for it. You could always take it to any welding shop and get them to build it as well. For now I am going to worry about getting this one built, then go from there.

Stay tuned for updates over the next couple days.

jet

03-15-2011, 12:24 PM

OK, the blade is 21" 1/2" wide and the supports are 9" apart. I had him measure the base plate at the attchment point, its 8" tall.

stinky_1

03-15-2011, 12:31 PM

wow, I would have thought the blade part would be longer than that. Looks like my 22" length will be enough there.

Thank you for all those measurements.

The biggest one I need now then is the distance from the back of the boat to the outer edge of the platform. This will end up being the maximum leg length for the wedge so that it stays under the platform when it is in the UP position.

Ill get to work on the rest tonight.

jet

03-15-2011, 12:42 PM

Man stinky you live UP NORTH!! You need to put that wedge on the front of your boat for a ice breaker..A!! lmao

stinky_1

03-15-2011, 12:53 PM

I expect the ice to be off the water in just over 1 month. Ill be in the water within a week of the ice coming off. I am hoping to get my boat soon. But the weather is playing a big role in that trip. The sooner I get it here the sooner I can get the whole thing installed and completed.

Once I have the final product on and tested I will throw some before and after pics of the wake. tHIS WAy it can be all packaged up in a way that everyone can decide if its something they want to do on their boat.

stinky_1

07-23-2011, 09:59 PM

So, here is an update:

I had to pull my tank out today so I could replace my rudder. It broker right off. While I have the tank off I am going to build my wedge and get it mounted. I have rode behind the boat and know I need to do something to get more wake anyway, so this is a must do.

It looks like the hull is reinforced where the middle swim grid support is. I am going to put my bracket on both sides of that. I measure it to be almost 2" thick there all the way up. Should hold up nicely.

More pics to come in a couple days when its complete.

chrisk

07-24-2011, 12:06 PM

Good luck Stinky, I know this is a thread that a lot of people are interested in

stinky_1

01-13-2012, 11:45 PM

Sorry guys that I have been asleep at the wheel here. I had some other maintenance I needed to do to the boat. Once summer starts there is no real time to fiddle with the boat and get stuff built and installed.

To further the problems I did hit an even bigger snag....... I sold the boat in Sept last summer!

So, thats bad news for all you guys I guess. But its kinda good news for me. It turns out I dont need to design a wedge after all. I just bought something that has it there all ready. Pics are below.

For everyone else I have not forgotten about you. I will get what I have cut up here all built and welded together. Ill snap all kinds of pics and post measurements. I know at least one of you guys are willing to test this for me, so it will make it onto someones supra. Then we can finally put to rest if these boats can take it or not. I am sure it is NOT going to be an issue. The transom on these guys are HUGE!

858685878588

Stinky,
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