DIY Wake shaper ideas

[haknslash]

I mentioned this in another thread but I didn't want to derail it any further. A problem with trying to delay convergence of a wave on our boats is that they simply don't sit low enough in the water on the non-listed side to allow for a wake shaper like a Ronix, Mission Delta or a suction-mount DIY wake shaper to work. There isn't enough side hull or surface area below the waterline not to mention the issue with graphics being porous so suction cups wouldn't hold. So I was wanting to come up with a way to have a surf gate similar to the Malibu surf gate design only this method would be using the two rear tie down strap tow points to lock in a tie bar, sort of like COtoFLSurf's rubber jet wash mat .

So here's my rough photoshop of the design...

And here is mock-up CAD design. it's all early right now in the design but I will run FEA stress analysis to ensure a design can be strong enough. I have CFD flow analysis software too but without an exact 3D model of a Yamaha hull this data wouldn't help much so I will just have to make a few prototypes at various angles. There is a common using of angles from an extensive DIY wedge thread on the mastercraft boat forums to give me an idea of what may get me in the ballpark.

And then here's a more traditional Malibu style with an actuator. It's basically a trim tab on its side. Actuator stroke would need to be long to allow 90° rotation. Obviously this would make the cost much higher as you would need to buy actuator(s). but what if it was manually done and you had locking positional pins instead? cost would come way back down then but of course would lose the nice electronic/remote aspect.

Thoughts?

 

[thcobb1]

So this is deployed on the non-surf?
Seems like it would not work with wedge if it required both tie downs. for support. Maybe the horse stall mats with it deployed on the side. If you wanted to surf both sides maybe a manual deployment method.

Make one up and I will be glad to test it.

 

[haknslash]

You could just use the rubber mat as a wedge like COtoFLSurf did for controlling jet wash. Yes the surf gate....err...."surf shovel" gets deployed opposite of surf side.

 

[KXCam22]

It will be nice to see what you come up with. I was toying with the idea of a plywood one for testing in the same spot you are looking at. The difficulty is attaching it to existing hardware for testing. Cam.

 

[haknslash]

It will be nice to see what you come up with. I was toying with the idea of a plywood one for testing in the same spot you are looking at. The difficulty is attaching it to existing hardware for testing. Cam.

Yup there's not much to attach to that's close to the transom. Only thing I could think of was mounting new hardware (which I'd hate to do for this kind of testing as it could all be for nothing and a bust in terms of delaying convergence with our hull design) or come up with a way to use the tow loops and make an "extension bracket" to mount the gate as close to the transom as possible. My gut tells me this may work so long as we can keep the gate close to the rear of the boat transom (not swim platform).

 

[thcobb1]

I really like an aftermarket product that is made of the same material as the wedge that deploys with an actuator and fold back inline with swim deck when not in use.

But does the deployment of this device push the rear of the boat to the surf side? If so, would you not just wash out the wave? Seems like it would make the boat track sideways to some degree.

 

[thcobb1]

What about the older moomba a setup? It is a metal plate that hinges out manually.

 

[haknslash]

I really like an aftermarket product that is made of the same material as the wedge that deploys with an actuator and fold back inline with swim deck when not in use.

But does the deployment of this device push the rear of the boat to the surf side? If so, would you not just wash out the wave? Seems like it would make the boat track sideways to some degree.

That's what all of the side gates/wedges do. They cause the boat to displace more water at a longer/slower rate on one side of the boat so that it causes a 'delayed' convergence of the wake behind the transom.

I don't think you're going to find too many aftermarket companies selling an actuated kit that is similar to OEM as all of the surf boat manufacturers have patents on their surf designs.

The surf boats that use wedges can be weighted with ballast evenly but I don't think any Yamaha will ever be able to do that because we simply are too light of boats and don't displace a lot of water. I think we will always need to be listed to one side unfortunately.

 

[swatski]

@haknslash FWIW, I can attest that the @COtoFLsurf mounting brackets for "surf flap" work very well - without any modifications to the boat. I have manufactured two different ones, a "strait down" and a 30deg "angled" variety, both worked well in my (very cursory so far) testing. I would think you could easily adapt that platform for your new gizmo. Heere is the angled one:


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[haknslash]

Yup simple and loved how those turned out. I would do the same for mounting the bar.

My biggest concern is the hull strength of these boats. As you know they are pretty thin in a lot of places. Last thing I'd want to do is install something like this for testing and rip my swim platform off . I know @Bill D 's 242 has reinforced tie down loops. I think the previous owner did it because he had a hoist for storing the boat or something. If it was able to hold the boat I suppose that's good but something to consider.

 

[KXCam22]

I dont think you have to worry too much about hull strength at the transom. I towed a boat off a sandbar using the trailer tie loops and full power. Besides, if those suction cup and velcro ones stay on? But oh to have a forward attachment point of some kind. Cam

Ps First pull, I am embarrassed to say, pulled the back off HIS boat. All I got was 18" square of fiberglass with his boat name on it. Oops. Bad condition though: I was too far away to tell where he hooked the rope, two 75' tube length ropes away, fast cross current in a river and I was in about 18" of water. I had to anchor, walk over and connect the rope myself for the second try. He was not upset since I think he realized that I was the only boat in the water that could get close enough.

 

[swatski]

@haknslash I'm looking forward to what you find albeit @jcyamaharider experience with the Ronix shaper makes me somewhat skeptical. I think that modified trim tabs may have a better chance of working, but I hope I am wrong on this.

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[haknslash]

@haknslash I'm looking forward to what you find albeit @jcyamaharider experience with the Ronix shaper makes me somewhat skeptical. I think that modified trim tabs may have a better chance of working, but I hope I am wrong on this.

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If you look at where he had to mount the Ronix shaper you can see it's very forward compared to where other traditional boats use it and it's also too high and not really below the water line. That's no fault of his but rather an issue with our jet boat design and limited surface area at the side / back of the boat. Our boats don't have enough hull surface on the side, especially below the water line to do any real good. Look at the first picture of my boat in the water and you can see the black gelcoat just above the waterline is part of the V hull. Everything else above is where you would need to mount a Ronix but the issue is that its out of the water more than in could be in it. Same for those DIY wake shapers people make with Handle On Demand suction cups that mimics the Mission Delta, Roswell and other aftermarket wake shaper devices.

Take a look at any Yamaha boat on the non-listed side sitting in the water or while underway and you'll see there's nothing really down in the water on the side of the hull. Now think of what happens to that side when you list the opposite side for surfing. Opposite side of the boat will sit higher while the other side sits lower. IMHO there's just not enough in the water to have an effect using those devices and this is why I feel he didn't have success on our boats. Next time you're out in your boat look over the side at any speed and you'll see how much is actually in the water back there and how much of the side hull isn't. Traditional surf boats don't have this issue as they have tall hulls that sit way below the waterline when weighted with ballast. When they use a wake shaper they typically will distribute the ballast weight evenly and no longer need to list, unlike our boats because we simply can't displace as much water because our hulls won't sit as low below the water line.

Image below is of the Ronix 8.3 installed. I don't think that surface is going to be below he waterline to make any kind of real impact for shaping the wake. Just like my boat the black gel coat on his boat is actually where the waterline sits just below a few inches.

 

[Bill D]

I think a delayed convergence system has a better shot on a single engine boat too. The twin jets present a unique situation behind the boat. I was impressed by the wave @haknslash was able to get with just a (relatively) small bag on board. If you get the weight set up right, it makes sense that a device like this could help. I'll look forward to seeing your progress!

 

[swatski]

If you look at where he had to mount the Ronix shaper you can see it's very forward compared to where other traditional boats use it and it's also too high and not really blow the water line. Our boats don't have enough hull surface on the side sitting BELOW the water line to do any good. Look at the first picture of my boat in the water and the black gelcoat above the waterline is part of the V hull, everything else above where you would mount a Ronix is out of the water. Same for those DIY wake shapers people make with suction cup handle on demand that mimics the Mission Delta wake shaper or similar device.

Take a look at any Yamaha boat on the non-listed side sitting in the water or while underway and you'll see there's nothing really down in the water on the side of the hull. This is why I feel he didn't have success on our boats. Next time you're out in your boat look over the side at any speed and you'll see how much is actually in the water back there and how much of the side hull isn't.

Image below is of the Ronix 8.3 installed. None of that surface is going to be below he waterline to make any kind of real impact for shaping the wake. Just like my boat the black gel coat on his boat is actually where the waterline sits just below a few inches. If you lost the bot then it gets even higher but that black portion of the hull can't be used as its only a few inches tall before it goes into the V.

Oh I get it. And you are absolutely right about a common misconception -- most people looking at those devices naturally assume those are mounted on the surf side, but in really the listing goes the other way and pulls those out of the water, worse yet in a Yammie.

Yamaha hull build is kind of deceptive as it is way recessed under the swim platform. Compared to a traditional hull/transom, looses at least 1+ foot of length (a traditional swim platform would be a bolt-on not counting towards LOA). A shaper will "extend" the side of the hull, but that hull is still too short to provide enough of a push. I think that a Yammie hull would benefit most from the Tige Whale-Tail-like (now abandoned) extension but that is not possible with the jets. And that is where a custom trim tab with a wide span and some crazy mod/extenders can possibly shine, as those are extending the bottom of the hull w/surface already angled (kind of) the right way, when mounted along the V-bottom of the stern all the way to the chine.

@Bill D is of course right about singles being more forgiving than twins in forming the wake, and with the SHO you should be able to use enough ballast. But the general concept is the same, and I'm watching!

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[jcyamaharider]

If you look at where he had to mount the Ronix shaper you can see it's very forward compared to where other traditional boats use it and it's also too high and not really blow the water line. That's no fault of his but rather an issue with our jet boat design and limited surface area at the side / back of the boat. Our boats don't have enough hull surface on the side, especially below the water line to do any real good. Look at the first picture of my boat in the water and you can see the black gelcoat just above the waterline is part of the V hull. Everything else above is where you would need to mount a Ronix but the issue is that its out of the water more than in could be in it. Same for those DIY wake shapers people make with Handle On Demand suction cups that mimics the Mission Delta, Roswell and other aftermarket wake shaper devices.

Take a look at any Yamaha boat on the non-listed side sitting in the water or while underway and you'll see there's nothing really down in the water on the side of the hull. Now think of what happens to that side when you list the opposite side for surfing. Opposite side of the boat will sit higher while the other side sits lower. There's just not enough in the water to have an effect using those devices and this is why I feel he didn't have success on our boats. Next time you're out in your boat look over the side at any speed and you'll see how much is actually in the water back there and how much of the side hull isn't. Traditional surf boats don't have this issue as they have tall hulls that sit way below the waterline when weighted with ballast. When then use a shaper they typically will distribute the ballast weight evenly and no longer need to list unlike our boats because we simply can't displace as much water because our hulls won't sit as low below the water line.

Image below is of the Ronix 8.3 installed. None of that surface is going to be below he waterline to make any kind of real impact for shaping the wake. Just like my boat the black gel coat on his boat is actually where the waterline sits just below a few inches. If you lost the bot then it gets even higher but that black portion of the hull can't be used as its only a few inches tall before it goes into the V.

That ronix was mid to 3/4 way under water when I was fully ballasted and also that was just a picture. You can see that the velcro actually went way farther back past my ve ve guides.

 

[haknslash]

There's only so far back you can go though with the Ronix or other shapers because of the rub rail getting in the way. On my boat it's even more of an issue for available space as my hull is not as tall as the larger boats. Damn Yamaha "swoosh" shape grrr lol. There's no way I could ever realistically run 3250 lbs of ballast on my 19' boat and still have room to drive and enjoy the day lol. Next time you're out on the boat I'd love to see how the Ronix looks with about 1200 lbs while at surf speeds and also how it looks without the Ronix installed in the water. It would help me get a grasp on just what surfaces are near the waterline while underway. I know when I listed mine with only 700-725 lbs on port bench the other side was definitely higher off the waterline. Are you evenly weighted or list your boat?

In the end I'm just trying to come up with something that may help us shape a wake. If it doesn't work no biggie but at least we'll know . We need all the help we can get for our boats so I welcome anyone coming up with something to help shape a wake, especially for us 19' guys.

 

[jcyamaharider]

I have pulled all Velcro off of my boat to put the ronix back on, but I think I have some pictures somewhere. My boat is weighted more to the port side but I do have ballast on the starboard side to sink the entire back of our boat.

 

[RightStuff]

Would mounting the wake shaper to the bottom (but as far to the side as possible) be of any benefit? Wouldn't it act similar to a trim tab deployed all the way down? There is a lip/step (chine?) of the hull that appears wide enough to mount the Ronix or some other plate like device. Like either of these spots:


Understandably it wouldn't be as convenient as you would have to put it on before putting the boat in the water, or reaching underwater to stick it to the velcro strips, but in an effort to try anything/everything...

 

[haknslash]

To mount a Ronix that low you would need to make one heck of an extension shim to reach the lower red rectangle which is also at an angle as opposed to the top red rectangle, so the effective contact of velcro on the shim would be less than the width of the velcro on a flat surface. I would imagine the force of water passing over such a long extension shim would cause it to fall off eventually if not immediately. The most ideal place to mount a wake shaper is as far back and close to the transom as possible on that side. The issue with Yamaha boats is the rub rail and not having enough flat surface to work with. So a Ronix would need to be forward enough to clear rub rail and such.