22 vs 24

[Ewok]

Man, I wish it were earlier in the season and that I had fat sacs. I would LOVE to be playing around with this stuff. I'm jealous that all I can do is mental gymnastics.

Be patient, we will have lots of time to play with these theories and concepts next spring. I have a few launchpad bags and we can fill up some sandbags and then compare/contrast the waves we form on the 24Ve and RZ2

[majestic]

Chris martinez was behind our RZ2 this weekend, and he definitely felt the shape was very similar, but he noticed our wake had more push, noticeably more. He is going to try to weight his boat more like we did, and see what happens. That will be a good experiment. He has a 22Ve.

I will try to do some testing this week. Seattle weather is touch and go this time of year

I will say your boat did have more push than mine with you in the ballast boy seat instead of Dennis, but I still think there is a difference in hulls. My boat does not seem to react well to bow weight. My boats wake was similar to yours with no bow weight and Dennis in the ballast boy seat. I think what may make them close to the same is you have the custom sacks and the 250lb underfloor getting all the weight in the back corner plus the 400 up front versus I have 1000lb sacks that travel further forward pushing the bow down a little more.

I will try filling my 1000lb sac and put 400lb in the ballast boy seat and 300 to 400 up front and see the result.

[IDBoating]

My interpretation of WAboating is he is talking about the lean or angle of the rear of the boat port to starboard. Weight on nonsurf side assumes surf side rub rail will raise and need more weight to bring rub rail on surf side back down. If you are puting rail to water, weight any where else will adjust list angle of boat. I would imagine that weight on nonsurf side would onlymellow out wave. So how much of an angle produces the best wave I'm thinking.

Imagine the boat as being like a plank of wood balanced on a volleyball. Additional weight on the plank will do two things: Change the tilt of the plank, and compress the ball a bit more.

You're talking about tilt, which is very important. In fact, ragboy has specifically mentioned (in another thread) that the 24's hull can tune the wave based on tilt.

I'm talking about tilt, but I'm ALSO talking about compression of the volleyball, i.e. how far down in the water the hull is sitting. It's been mentioned that the 24's larger hull has more buoyancy; it floats higher in the water with the same amount of weight. We must consider that in addition to tilt.

Adding weight to the nonsurf side, alone, will indeed raise the surf side. But think about what that does: It allows you to add more weight to the surf side too (which you presumably couldn't do before if the rubrail were already at the waterline). With more weight on both sides, the hull sinks even deeper into the water, displacing more water, which is how the wave gets formed in the first place.

I agree that weight added to the nonsurf side, alone, will mellow out the wave. But once you achieve the tilt you want for the hull in question, adding weight symmetrically to BOTH sides will deepen the hull displacement while keeping the tilt roughly unchanged. And that (coming full circle to the original topic) may offset the effect of the longer hull with its imaginary "500 pounds" of ballast up front. It may permit the 24's to mimic the wave coming off the 22's.

To summarize, the 24's imaginary bow ballast affects both the depth of the stern (because it's forward of the CoG) AND the tilt of the stern (because it's symmetrical to the centerline). I'm theorizing that we may need to offset BOTH effects to put the stern portion of the hull in the same place, and thus generate the same wave, as the 22's.

[talltigeguy]

My interpretation of WAboating is he is talking about the lean or angle of the rear of the boat port to starboard. Weight on nonsurf side assumes surf side rub rail will raise and need more weight to bring rub rail on surf side back down. If you are puting rail to water, weight any where else will adjust list angle of boat. I would imagine that weight on nonsurf side would onlymellow out wave. So how much of an angle produces the best wave I'm thinking.

I think Ragboy has stated that some of the wave configuration is made by the side of the hull, not the bottom. And that makes sense if a boat is listing heavily to the weighted side when moving. So some of the wake is made by the 'list'.

My boat, for example, does better with some weight on the non-surf side. This sinks the entire hull and decreases my 'list'. I believe that the majority of the wakemaking capacity is created by the 'sinking' of the boat and the list is a factor mostly in the shape of the wave.

I don't know what this has to do with anything, but it is my theory on wakemaking.

[IDBoating]

My boat, for example, does better with some weight on the non-surf side. This sinks the entire hull and decreases my 'list'. I believe that the majority of the wakemaking capacity is created by the 'sinking' of the boat and the list is a factor mostly in the shape of the wave.

I completely agree, and your experience in your first sentence coincides with my theory. That's why I suspect the 24's wake will improve by adding weight to BOTH sides of the stern once the desired tilt has been achieved.

We're all waiting for the results of ragboy's tests....

[ragboy]

On the RZ2, it doesn't like weight on the opposite side at all. All of a sudden you will see prop wash come over the wake, especially if you have the taps down lower.

When we were experimenting with many options on the 24Ve, and 900 lbs of pop bags and water, back in october 2008, we definitely found the boat made a better wake when all weight was in the one corner.

[ragboy]

I know that Mark Sher was telling me his enzo likes some weight on the opposite side also.

[Nobody]

This is heavy stuff.

[Duncan]

On the RZ2, it doesn't like weight on the opposite side at all. All of a sudden you will see prop wash come over the wake, especially if you have the taps down lower.

When we were experimenting with many options on the 24Ve, and 900 lbs of pop bags and water, back in october 2008, we definitely found the boat made a better wake when all weight was in the one corner.

I think one of the points above is, past a certain point of weight on one side (i.e., the perfect list angle), additional weight added equally to both sides will not change the optimized list of the boat, merely the sink.

Of course, that hypothetical point may never be (sanely) reached (i.e., more and more list produces a better and better wave); if you cannot safely reach max/ideal list, then you can never optimally add to both sides for sink.

[ragboy]

The only issue with that is, the optimal angle seems to be, rubrail kissing. More sink would put the rubrail underwater. I have done this for R&D purposes. 2 things happen.

1. Rubrail cuts into the wake. Probably is more cosmetic, but definitely makes it dirty.
2. Unsafe. Water up this high, over the rubrail is unsafe in my opinion unless glassy conditions, no other boats.

Hmm, one more thing. We noticed when weighted like that that when you adjusted Taps up to 3+, the wave actually started to distort, it was very strange. The weight we had this weekend, with the custom sacs, the wake was about as big, and as much push, but was CLEAN, and didn't have this weird distortion. We put taps up to 5 once, with Mitch riding, I will find the video. The wake just turned into a WALL behind him. It was funny. It got way short, but it was a literal WALL. You can't tell as much in the video, but in the boat, it was cool. No distortion in the wave.

[murphini]

This would make a great College-Engineering case study in Fluid Dynamics class. (If the numbers on my slide rule weren't so dang small that I can't read them anymore, I'd 'weigh in' with my calc's.)
x(t) = A\cdot \cos( 2 \pi f t + \theta )\,

Better yet: I am all for applying whatever Ragboy's real-world experiments turn up. Figure out the wave-weight constant so I can improve my meager surfing skills.

[AdaminMN]

The 24 footer has more volume, therefore more bouyancy. Nobody has mentioned the extra lift generated by the running surface of the hull.

The 24v weighs less than 200# more than the RZ, but the extra two feet of hull probably generated five times that in lift. SInce that lift is generated across the entire beam of the boat, I would think thatyou would have to weigh down the "high" side of the boat too.

[Duncan]

The only issue with that is, the optimal angle seems to be, rubrail kissing. More sink would put the rubrail underwater. I have done this for R&D purposes. 2 things happen.

1. Rubrail cuts into the wake. Probably is more cosmetic, but definitely makes it dirty.
2. Unsafe. Water up this high, over the rubrail is unsafe in my opinion unless glassy conditions, no other boats.

Well then, we can all expect to see in a few years specialized wakesurf boats with goofy looking tall rear sideboards

I think part of what makes a Tige a great surf boat is the relatively tall gunwale (compared to other wake boats).

[ragboy]

First, let me preface. I consider myself an expert with technology and software development, but not boats, buoyancy or hydrodynamics. So if I disagree or wax on, take it with a grain of salt. I have gained a lot of hands on experience with this, and that is the primary fuel for my thoughts. This is just fun for me, October is always R&D month for us, and I enjoy working this stuff out.

That said, I don't think buoyancy is the issue, it is definitely A issue, but I think it is more than that. I think it is more of an issue of leverage. In wakeboarding, the boat sits more flat on the water, and you weight the whole thing down, in wakesurfing, you ride very bow high, and the pivot point is very much in the rear since the boat is NOT on plane. Wakeboarding, the boat is on plane, and the pivot point is much more forward.

So what generates a surf wake?

1. The List angle of the boat
2. The Bow rise angle of the boat.
3. How deep the hull is sunk in the water
4. The speed of the boat.
5. Taps, but this is more about adjusting angle, so see 1 and 2. Although taps can help with wash, and other aspects.

Look at these 2 videos, you only need to watch beginning of the safety video to see the full side view of the boat.





The boats have a similar angle when weighted for a good wake. The RZ2 seems to be a little more nose up, but I will measure the angle when I can and report back. I have one of these I just bought:

http://www.amazon.com/gp/product/B00...ef=oss_product

The 24Ve has ZERO weight in back in this video, and the RZ2 has almost 600 lbs. 400 up front, and then 200 just forward of driver area on surf side. If you look, the boat sits up on the water, up to about the windshield. If you look at the bottom of the hull, that is about where the apex of the bow rocker is. That apex of the front rocker, is at least 18" forward on the 24 foot boats over the 22. Also, if you look at the bottom of the hulls, the there is the convex V rocker from this apex to the back of the boat. Due to the longer 24 foot hull, this area is flatter on the 24, and more of a continuous rocker on the 22. That said, the 22 foot boat, not only has less surface area on the water, it is much easier to adjust its bow rise, especially up. My guess is, whatever the magic angle for bow rise, it is MUCH easier to achieve on the 22 than the 24. On the 22, you have adjustment up and down around that magic angle. On the 24, you have to weight the hell out of the corner just to get it there.

Remember also, that if the pivot point, or fulcrum is at the rear, weight up front as at the end of the lever. So on a 24 ft boat, weight up front has a much greater impact, keeping the bow from rising to that magic angle.

Again, I could be fartin in the wind here, but this makes more sense, to what I see in actual experimentation. Its not about the amount of weight, its about attaining the magic orientation of the boat, and sinking down from that point.

It does stand to reason that when this magic orientation is reached on the 24, it could throw a bigger wake, but there is another obstacle. The 24 foot boat is longer, but not to scale. So the rubrail and freeboard are the same on both boats. This means you may not be able to sink the boat deeper at that angle, without being unsafe, or the rubrail cutting into the wake, which gives the RZ2/22Ve another advantage.

One last advantage to the RZ, I just noticed today on some video, I think the rubrail is higher on the RZ vs the Ve. The distance from the rubrail to the gunwale on the Ve, seems greater than the RZ. This allows the RZ to sink down even more than the Ve.

[ragboy]

A couple of pictures that might help.


image by wake9, on Flickr


IMG_3303 by wake9, on Flickr


IMG_3312 by wake9, on Flickr

I can tell from my experience getting my fat butt in the RZ2 or the 24ve while on the trailer, the 24Ve is MUCH easier. This may be why the RZ has more push, able to sink down more, and list more.