Surf wave brainstorm

Has anyone looked into the new innovation from Malibu called the Surf Gate?

http://www.malibuboats.com/news/surf-gate/

I know I'll probably get some flack from some of the "old school" surfers here . . . but this is just a brainstorm so here goes. :p I pretty much have no room for ballast on my Sunsport unless I take up valuable floor space or storage space. We get a pretty good surf wave using MBU's (mobil ballast units = people), but we don't always have the crowd for that and I get embarrased asking my friends to come along for the ride because I need weight! :D

So here's the question . . . if the Malibu Surf Gate really works, then what about modifying the swim platform on my Supra with side fins to mimick the surf gate? Would this be too much stress on my swim platform mounts? What do you guys think?

Here's a pretty cool video on the subject. A little long, but good especially if you dig the Dave Matthews Band.

http://www.youtube.com/watch?v=8AYgP...eature=related

At one point in the video you can actually see the boat sort of "crabbing" along, not tracking straight. So I guess the wave is achieved by puching the boat sideways a bit, displacing much more water than when tracking straight.

I think you would still have to weight your boat, and the idea behind the surf gate is that you don't have to weight it side to side. So if you put ballast in the ski locker and under rear seat and some up underneath the bow seats, then the idea would be a properly functioning "surf gate" would allow you to shift back and forth between waves. The gate doesn't create a bigger wave, it just changes the shape of it.

If you decide to pursue this, and successfully pull this off, I would love to look into it as well.

Yeah - you're probably right. All this new technology makes me want to replace my Supra with a newer model.

Yeah.. but where's the fun in not having any obstacles to overcome?!

I would still like to try adding a wedge like that to our boat.

Not sure how much beefing up the transom would need to hold.

Now that the weather has gone to hell its time to start looking at some winter projects.

I think the platform mounts would be a bit stressed. I am sure anything (wedge, fin, etc) properly reinforced can be added to any Supras transom...it then comes down to the boat operator, and operating conditions. I am sure a modified set up would drive differently. I think a modified "surf gate"set up could also stress the rudder and maybe center fins on older boats as well. No doubt it would work though. Great read. Super cool idea. Tabman, any ideas?

I saw the new Malibu system this week and the paddles are WAAY bigger than I thought they were. HUGE!

CSuggs, IF you decided to go this route and IF you decided you would need to beef up the transom platform supports then since you'll be getting behind there anyway you could go to the trouble of installing a wedge for down pressure like all the Malibu's have. THEN, feasibly, you wouldn't have to fill up as many sacs inside the boat taking up room and storage. You'd get "ballast" from the center wedge, and surf-wave-shape from the side flaps?

The reason there so big is you need the added surface area due to the slow speed. I'm wondering if the wedge does much either at slow speed.

The amount of down force the wedge has would all depend on the angle and surface area.

Do we have a hydrodynamics expert on here that could tell use the what angle and surface area we would need at a given speed to reproduce the effectsof a given amount of ballast.

Not trying to be sarcastic I don't have the knowlage to make this work properly on my hull.

Not hydro dynamics but it's a very similar principle as aerodynamics of which I know enough to be dangerous. But as said before, to compensate for a slower speed, you either need to increase the angle of attack or the shape of the wedge.

My thoughts on the idea are to make the angle of attack adjustable to compensate for lower speed(less flow).


Can you give us(me)some examples of the more efficient wing shapes.

All I have to start with as far as shape and size is the malibu wedge. The hulls are quite different so I don't know how well it will work.

I maybe mistaken but the wedges are designed for higher speeds like wakeboarding. Is the pitch adjustable? I'm assuming you can not put it down all the way but this would turn it into more of a drag brake than a downward force concept. I'm thinking (using my aircraft knowledge also) the whole wing would need to be redesigned with a greater surface area and greater pitch to compensate for the slow speed of wakesurfing.

Well, you could increase the angle of attack like I said thereby making the wedge/wing take a bigger bite of the water and exert a greater downward pressure, you could also change the camber without changing the angle of attack to compensate for a slower speed requiring more downforce. Check out this link and play around a little and see what I am talking about. If you have any questions after that, I will do my best to answer them.

http://www.grc.nasa.gov/WWW/k-12/airplane/foil3.html

Just quickly playing around with it, I was able to find a foil that exerts almost 4600 pounds of downward pressure while only creating 950 pounds of drag to overcome.

Thanks for the link I will play around to see what I can come up with.

I wonder if wood or fiberglass laminated over steel would hold to test different upper and lower camber profiles as having them machined will get rather pricey

The surf gate isn't like a wedge where it's pushing the boat up or down. I'm sure there's some slight upward pressure on the non surf side but that's not the main idea behind the surfgate.

What the surfgate dows is change the convergance of the wake (where the wake from the left side and the right side of the boat come together). By extending the paddle on the opposing side of surfing, you're essentially making the convergance on the non-surfing side further back. What that does is make the surf wave on the surfing side.

You still have to load the boat. You still need weight front and rear. It also seems like people are slightly loading the surfing side more still, but not like now where you have to have 500-1000 lbs more on one side to get the boat to lean. Maybe only 100-200 lbs more on one side of the boat more.

It also seems like there's not a whole lot of pressure added onto the teak. There's a couple guys that bootyfabbed a setup over on the Malibu forum, where they have have the paddle clamped to the teak. One Mastercraft guy reported maybe 80-100kg of force on the paddle itself. Makes sense since 5psi = 20mph, 11 psi = 30mph, 19 psi = 40mph, 30 psi = 50mph (Taken from a Airguide Speedometer writeup). So We'll say that the PSI at 10mph is 3psi. A paddle that is 10X20 at a 45 degree angle will roughly have 100square inches of surface area, equaling 300lbs of force. They're not at a 45 degree angle, more like 20 degrees, so the force is probably somewhere around 150lbs. The teak and transom is more than capable of holding this ;)

The only negative thing I have seen so far is that the paddle will make the boat want to track wierd when moving slow to pickup a rider. The new Malibu's do not have this problem because they automatically pull in at about 7 mph.

This may be my project for the summer. We surf behind the Comp a lot, and it's leaned over a lot. The problem is when we have goofy/regular footed riders, and it takes half an hour to switch everything over. With this setup, even if it wasn't hard mounted to the boat (making a couple paddles that quick connect/quick disconnect on the lake) the change over time would be dramatically reduced.

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Originally Posted by NorCalPR

The surf gate isn't like a wedge where it's pushing the boat up or down. I'm sure there's some slight upward pressure on the non surf side but that's not the main idea behind the surfgate.

What the surfgate dows is change the convergance of the wake (where the wake from the left side and the right side of the boat come together). By extending the paddle on the opposing side of surfing, you're essentially making the convergance on the non-surfing side further back. What that does is make the surf wave on the surfing side.

You still have to load the boat. You still need weight front and rear. It also seems like people are slightly loading the surfing side more still, but not like now where you have to have 500-1000 lbs more on one side to get the boat to lean. Maybe only 100-200 lbs more on one side of the boat more.

It also seems like there's not a whole lot of pressure added onto the teak. There's a couple guys that bootyfabbed a setup over on the Malibu forum, where they have have the paddle clamped to the teak. One Mastercraft guy reported maybe 80-100kg of force on the paddle itself. Makes sense since 5psi = 20mph, 11 psi = 30mph, 19 psi = 40mph, 30 psi = 50mph (Taken from a Airguide Speedometer writeup). So We'll say that the PSI at 10mph is 3psi. A paddle that is 10X20 at a 45 degree angle will roughly have 100square inches of surface area, equaling 300lbs of force. They're not at a 45 degree angle, more like 20 degrees, so the force is probably somewhere around 150lbs. The teak and transom is more than capable of holding this ;)

The only negative thing I have seen so far is that the paddle will make the boat want to track wierd when moving slow to pickup a rider. The new Malibu's do not have this problem because they automatically pull in at about 7 mph.

This may be my project for the summer. We surf behind the Comp a lot, and it's leaned over a lot. The problem is when we have goofy/regular footed riders, and it takes half an hour to switch everything over. With this setup, even if it wasn't hard mounted to the boat (making a couple paddles that quick connect/quick disconnect on the lake) the change over time would be dramatically reduced.

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you,ve done your research. i'll be making a quick release gate for my saltare in the spring along with a larger teak swimdeck.

I haven't seen one in person yet, but from the pics it just looks like a slightly big trim tab mounted sideways. Seems like that'd be a pretty easy thing to try, if you really wanted to.

http://theskimonster.com/files/thesk...-Deployed.jpeg

Nautique came out with the NSS last year it works similar but mounts to the transom . It looks much cleaner and wont affect the turning ability of the boat. Here is some info about it.




The Nautique Surf System with WAVEPLATE was designed to create the ultimate surf wave with ease. Gone are the days of offloading ballast and people from side to side. Leave the ballast filled after wakeboarding and with the touch of a button through the Nautique LINC System, you will be surfing your wave of choice in no time. The WAVEPLATE is an integrated design that when deployed extends outward and down from the transom intercepting and redirecting the flow of water to clean up the opposite wake and form a surf wave like no other boat.

http://farm9.staticflickr.com/8093/8...e32be280f4.jpg
Nautique214 by nautiquehunter, on Flickr

I have seen the Malibu surf gate if someone wanted to make one its not hard I have thought about it but the older model boats like I have I just don't know if it will handle it. it could be done with a large trim tab on both sides and a 12in by 12in by 3/4in thick piece of lexan or plexy bounted to the trim tab its not a bad Idea at all

Look at martin archers work on the Malibucrew forum. Look up teakgate.

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Originally Posted by 2500hd

look at martin archers work on the malibucrew forum. Look up teakgate.

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wowwwww!!!!

I do remember reading a Nautique owner ditched the setup after tinkering with it. He had the weird V which was on the old v-drive hulls.

I'm sure it doesn't work for every single boat out there because of the design of the hull, but I'm going to try it out with some clamps this year. If it works, I'll make a set that clips into the brackets for the swim platform...

you WILL need to strengthen your transom to mount a system like this. Both Mautique and Malibu's setups are only able to be installed on their newer built boats because they have restructured the transoms. You CANNOT install these setups on older models because of this reason.

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Originally Posted by wspeedin

you WILL need to strengthen your transom to mount a system like this. Both Mautique and Malibu's setups are only able to be installed on their newer built boats because they have restructured the transoms. You CANNOT install these setups on older models because of this reason.

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I beg to differ on the transom strength. from what i have seen, the lateral forces that the surfgate creates are not out of control. in fact i saw a post some where that said between 80-100kg. not sure how true that is but is does sound reasonable. Another reason is that I've seen it on older boats.
One thing that you should check on your transom is if the swimdeck is screwed to the transom or thrubolted. if it is just screwed i wouldn't try it.

http://i497.photobucket.com/albums/r...d/GOPR0018.jpg

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Originally Posted by 2500HD

I beg to differ on the transom strength. from what i have seen, the lateral forces that the surfgate creates are not out of control. in fact i saw a post some where that said between 80-100kg. not sure how true that is but is does sound reasonable. Another reason is that I've seen it on older boats.
One thing that you should check on your transom is if the swimdeck is screwed to the transom or thrubolted. if it is just screwed i wouldn't try it.

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I agree. One of the threads they did the calculations and estimated only ~200lbs of force put on the entire plate. With backing plates it should not be a problem at all.

Curious to see what happens when we get the chance to do some experimenting. I'm def. going to try some things out and if it helps with our boats, hopefully the Teakgate electronics package will come up for sale and we can all add it to our boats without too much fuss!

Quote:

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Originally Posted by wspeedin

you WILL need to strengthen your transom to mount a system like this. Both Mautique and Malibu's setups are only able to be installed on their newer built boats because they have restructured the transoms. You CANNOT install these setups on older models because of this reason.

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Simple math...

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It also seems like there's not a whole lot of pressure added onto the teak. There's a couple guys that bootyfabbed a setup over on the Malibu forum, where they have have the paddle clamped to the teak. One Mastercraft guy reported maybe 80-100kg of force on the paddle itself. Makes sense since 5psi = 20mph, 11 psi = 30mph, 19 psi = 40mph, 30 psi = 50mph (Taken from a Airguide Speedometer writeup). So We'll say that the PSI at 10mph is 3psi. A paddle that is 10X20 at a 45 degree angle will roughly have 100square inches of surface area, equaling 300lbs of force. They're not at a 45 degree angle, more like 20 degrees, so the force is probably somewhere around 150lbs. The teak and transom is more than capable of holding this

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I understand everyones point. However, I made my post based on the Manufacturer's warning. Both Malibu and Nautique have both stated that they cannot install it on older model year boats due to the strength required of the transom.
By all means, go and try it, but I will stick to listening to what manufacturer's have said about their products.

Quote:

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Originally Posted by wspeedin

I understand everyones point. However, I made my post based on the Manufacturer's warning. Both Malibu and Nautique have both stated that they cannot install it on older model year boats due to the strength required of the transom.
By all means, go and try it, but I will stick to listening to what manufacturer's have said about their products.

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I hear ya.....but if it makes my saltares goofy side a good wave then its worth it in my mind.

Quote:

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Originally Posted by wspeedin

I understand everyones point. However, I made my post based on the Manufacturer's warning. Both Malibu and Nautique have both stated that they cannot install it on older model year boats due to the strength required of the transom.
By all means, go and try it, but I will stick to listening to what manufacturer's have said about their products.

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That is probably due to the legal department and the engineering department trying to do some major "CYA." I get what you are saying as well and have no intention myself of surfing the comp so I don't really have a dog in this fight.

Quote:

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Originally Posted by wspeedin

I understand everyones point. However, I made my post based on the Manufacturer's warning. Both Malibu and Nautique have both stated that they cannot install it on older model year boats due to the strength required of the transom.
By all means, go and try it, but I will stick to listening to what manufacturer's have said about their products.

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This is a game changer and they know it will sell new boats. I'm not surprised that they don't offer it as a retro-fit.

Quote:

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Originally Posted by wspeedin

I understand everyones point. However, I made my post based on the Manufacturer's warning. Both Malibu and Nautique have both stated that they cannot install it on older model year boats due to the strength required of the transom.
By all means, go and try it, but I will stick to listening to what manufacturer's have said about their products.

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Of course they can't, because that would mean they don't sell new boats with the new technology. It's the idea that why buy a new boat when you could just retrofit your old one...

They didn't come up with the design to retrofit old boats, they came up with it to help sell their new boats. Look at the new Tige with the Convex VX. All this new technology that's coming out is revolutionizing surfing. Every manufacture has to come up with something to stay ahead of the game...

Remember back in the day when towers couldn't be retrofitted to older boats because the hull was too weak? ;)

This is the exact reason till aftermarket catches up.