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  1. #1
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    May 2013
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    Default The basics of Surf Systems (and platform modifications)

    I've had some questions from people that are newer to the surf system game, so I'll start a thread here to hopefully answer some questions and help out more than just one person.

    What is a surf system?
    A surf system is any device that's added to your boat that operates on the non-surf side to delay the convergence of the two wakes coming off the back of your boat. By delaying the convergence, it cleans up the wave on the surf side and lengthens the pocket. It also has the tendency to allow you to weight your boat evenly (or more evenly) as opposed to slamming the rear corner. When you add a surf system device, there's an inverse relationship between the angle to the hull at which it deploys and the length of the blade/tab. (for example, a surfgate is easily a foot an a half with a shallow angle {~20 degrees} while the NSS is only 3" but is at a 90 degree angle to the hull)

    Why would you want a surf system?
    The ability to evenly weight the boat allows for a more comfortable experience for the driver and passengers. It also allows for quick changes from regular to goofy because you're not having to drain ballast, move ballast and refill ballast. Often a surf system will allow you to run less overall weight and still maintain a clean, surfable wave. Sometimes a surf system is used to clean up or lengthen the wave.

    What are the drawbacks of a surf system?
    Many people are adverse to making permanent modifications to their boat. If you're going to do the direction of a temporary system, then you've got something that you have to figure out how to attach and stow when not in use. You've got to have a little DIY knowhow and be willing to fabricate and EXPERIMENT.

    Most will attest that to get the absolute BEST wave period, that there's "no replacement for displacement". Simply put, MORE WEIGHT is typically hard to beat when it comes to getting the BEST wave you could get. That said, life is about tradeoffs and those of us with surf systems are using them to get a good/great wave while simultaneously making things better as far as boat drivability, fuel consumption, convenience, etc.

    What surf systems are out there?
    There are a handful of surf systems out there, and most of them have been copied or retrofitted in some way or another.

    1) Malibu/Axis Surf Gate.

    This is the original. it's a gate on the side of the boat that deploys at around a 20 degree angle. They are powered by a Lenco trim tab actuator and are basically functioning as a sideways trim tab. in the most recent 2014 versions, they have been upgraded with faster actuators so the gates will deploy/retract in about 3 seconds, allowing transfer tricks from regular to goofy and back.

    2) Natique Surf System (NSS) {also used by Pavati}

    The NSS is a blade that is deployed on the edge of the hull. It extends about 3" out and about 3/4" to 1" down. It had varying levels of adjustability to change the wave from surf to skim. It is likewise power actuated and enables on the fly side to side transfers.

    3) Supra Swell (Also MB Switch and sort of Mastercraft Gen2 surf system)

    Supra stepped into the game by putting special shaped trim tabs on each side of the BOTTOM of the transom. Supra and MB systems will actually deploy a trim tab fully horizontal on the opposite of the surf side. Mastercraft does the same type of thing, but I don't think their tabs go as far down (so they're accordingly longer).

    4) Moomba Flow

    Moomba is kind of unique in that they stepped up with a manually actuated surf system. It's a blade that can be deployed in 4 different settings from more outward to more downward. It pivots with a spring loaded locking pin.

    What system is the best?
    Honestly, all of the systems have their advantages and disadvantages. Each manufacturer will praise their own system. Some offer adjustment of the wave, some offer simplicity, some offer a price advantage. But all of them are attempting to do the same thing: Delay convergence of the wakes coming off the rear of the boat.

    What DIY systems have been created to mimic/retrofit what the new boats are getting?
    Keep in mind that some of the boat manufacturers have filed for patents on their systems. And many of the boat manufacturers have copied other people's systems or made knockoff's anyway. I am not a lawyer and can't advise what's okay and what's not okay when leveraging someone else's ideas. But I guess I will say that you're less likely to encounter problems if you don't try to sell retrofitted surf systems that greatly resemble something one of the boat companies has a patent on.

    The first system to be retrofitted was of course the surf gate. There are many iterations of this that have been done. You can search on these terms and find lots of write-ups that have been done on these. The first two are automated and permanent, the last two are manual and able to be taken off when not in use.
    • Poor Man's Gate
    • Teak Gate
    • Cornrickey Surf gate
    • Ghetto Gate (note, there are versions of this that come out at an angle to the hull like the Malibu surf gate, and versions that come straight out as an extension of the hull. Both work but the straight ones tend to be longer)


    A few of us have retrofitted an NSS style system onto our boats. I chose to go this way because the rear hull of my boat is basically flat and it would allow me to have something that's out of the way when not in use that I DON'T have to take on or off. This is a manually actuated system with blades that slide out sideways from the hull. It's made from HDPE and stainless bolts. The install on this is more time consuming than some and materials aren't too bad but are more than some of the basic designs. It's most certainly permanent and required drilling quite a few holes in my hull.
    My write-up: http://www.moomba.com/msgboard/showt...-after-the-NSS

    There are always going to be critics about the extra force/strain that's being put on your hull. All I can say is think it though and install things as robustly as you can. Obviously, if you wreck your hull, it's not my fault and I take no responsibility! Ha!

    I know there have been a handful of retrofits of surf tabs. I mean, all you really have to do is get a trim tab kit and mount it up. I think the most effective designs are those that deploy fully downward like Supra Swell, and not many people have been able to fab up the extra bracing/reinforcement for the trim tab actuators... yet.

    Which system should you try to retrofit?
    • Really, I can't answer that for you. Again, you have to determine your goals.
    • What is the shape of your hull that you'll be installing the system on?
    • Do you want adjustability?
    • Do you want it automated?
    • Is cost of the project a big factor?
    • Are you okay with something permanent?
    • Do you want quick side to side changeovers?
    • Do you want something that doesn't require being taken off and stowed when not in use?
    • How handy are you at fabrication?


    Swim platform effects
    I'll briefly touch on the effects of swim platform on the surf wave. In short, if your platform is dragging in the surf wave as it comes off the back of your hull, that's typically bad. The worst is when you have a fiberglass platform with a big lip that's cutting into the wave. This will typically rob the wave of power and make it less clean.

    The solution is simple. Have a platform that is smooth on the bottom and best case scenario, NOT dragging in your wave.

    If you have a teak platform, you can trim it. If you have a fiberglass platform, you'll likely just replace it. Some have made them out of teak, or wood coated in fiberglass, or out of HDPE, or even textured HDPE (Like Grip-X). the basic shape needed is a trapezoid where the corners of the platform that would ordinarily drag in the wave are cut off. (like cutting the corners off the rectangle of the platform).


    I hope this article gives some overview and insight into why a surf system might be attractive and the things you need to start thinking about when deciding if and how you might put one of these on your boat.

    Happy Surfing!
    2008 Moomba Mobius XLV. Monster Cargo Bimini, and more mods to come...

    1992 Supra Sunsport. **SOLD** 2k pounds ballast, Surf System, Blue LED's everywhere, decent audio system.


    Tow Rig: 2009 Honda Ridgeline RTL (wife's rig) Other money pits include:1998 BMW M3 Cabriolet, 2000 Jeep Wrangler rock crawler), 1999 Audi A6 Avant, 2005 Kawasaki ZX-6R 636.

  2. #2
    Join Date
    Mar 2014
    Location
    Park City, Utah
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    250

    Default

    This is perfect. I am looking at all my options now to determine what way to go. I have a good pocket but it is not long. Trying to add more weight, but the wife needs to be comfortable driving. Thanks!
    2006 Mobius LSV
    2004 Stingray 190LS - Sold
    2013 RAM 2500 Diesel - Tow Rig

  3. #3
    Join Date
    Jan 2008
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    Tallahassee, FL
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    11,347

    Default

    Nice writeup Trayson. It would take hours to track all of that down. Filled in some holes for me.
    My Mom said I'm not allowed to get wet!
    2008 LSV
    2000 Outback LS (sold)
    Exile Tunes
    PWI
    LLTR!!!!!!!!



  4. #4
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    May 2013
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    Vancouver WA
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    Quote Originally Posted by sivs1 View Post
    This is perfect. I am looking at all my options now to determine what way to go. I have a good pocket but it is not long. Trying to add more weight, but the wife needs to be comfortable driving. Thanks!
    From a "try it before you buy it" perspective, the recent "ghetto gate" creations seem to be the quickest, easiest, and cheapest to do and are also temporary.

    Personally, I was able to leverage someone else pioneering the NSS style system so I just jumped in and committed. But for someone just wanting to try it out, I'd say Ghetto gate seems the most straight forward.





    2008 Moomba Mobius XLV. Monster Cargo Bimini, and more mods to come...

    1992 Supra Sunsport. **SOLD** 2k pounds ballast, Surf System, Blue LED's everywhere, decent audio system.


    Tow Rig: 2009 Honda Ridgeline RTL (wife's rig) Other money pits include:1998 BMW M3 Cabriolet, 2000 Jeep Wrangler rock crawler), 1999 Audi A6 Avant, 2005 Kawasaki ZX-6R 636.

  5. #5
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    Quote Originally Posted by kaneboats View Post
    Nice writeup Trayson. It would take hours to track all of that down. Filled in some holes for me.
    Thanks. I've been obviously researching this from the beginning and have followed it pretty closely. I tried to cover it as there's a lot going on, and things continue to be invented every week.

    In some respects the people that wait tend to have the best opportunity for results because they can leverage the trial and error of others. Myself, like others will typically implement a system and stick with it.

    In hindsight, there are some things I'd do differently with mine (like make my blades out of black HDPE so they disappear more visually). But overall, I'm quite satisfied.
    2008 Moomba Mobius XLV. Monster Cargo Bimini, and more mods to come...

    1992 Supra Sunsport. **SOLD** 2k pounds ballast, Surf System, Blue LED's everywhere, decent audio system.


    Tow Rig: 2009 Honda Ridgeline RTL (wife's rig) Other money pits include:1998 BMW M3 Cabriolet, 2000 Jeep Wrangler rock crawler), 1999 Audi A6 Avant, 2005 Kawasaki ZX-6R 636.

  6. #6
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    May 2013
    Location
    Fairfax, va
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    Trayson thanks for putting this together! I have done a lot of searching around but haven't come up with anything that really explains things from top to bottom. Glad you have been at it.

    I am guessing the wake convergence is trying to keep the wake created by the side of the hull from converging with the wake created by the bottom of the V hull for as long as possible? That is what I am gathering from the Ghetto Gates you are showing in the pics.
    2007 XLV Gravity Games
    1,100 in each rear locker
    1,180 in front ski locker
    OJ 1435 prop, 325 EFI Indmar Assult.
    Racks added for surfing and kneeboarding.
    Rack for hydrofoil

  7. #7
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    Quote Originally Posted by 5:00 View Post
    Trayson thanks for putting this together! I have done a lot of searching around but haven't come up with anything that really explains things from top to bottom. Glad you have been at it.

    I am guessing the wake convergence is trying to keep the wake created by the side of the hull from converging with the wake created by the bottom of the V hull for as long as possible? That is what I am gathering from the Ghetto Gates you are showing in the pics.
    Well, the wave is created from forces coming off the bottom and side of each corner. so for simplicity, we'll talk about it as coming off just the sides of your hull. if they're coming off the hull equally, they meet in the middle and create a lot of turbulence. it looks like a big giant mess of whitewater with no gates/blades. When you put out a gate or a blade on the non-surf side, you're slowing that wave down and it's meeting the centerline of the boat farther back from the stern.

    What this does is allow for the surfside wave to develop more fully and in turn be longer and cleaner/smoother. to some extent delaying the non surf side wake will actually send it under the surfside wake and boost it up and make it a little bigger. (I'm not 100% sure of that theory, just seems to be my observation).

    I'm not an expert in hydrodynamics, but that's my understanding. basically delay one of the wakes so the turbulence is farther back and the surf side is as long and smooth as possible because it's not getting affected by the other wake as soon.
    2008 Moomba Mobius XLV. Monster Cargo Bimini, and more mods to come...

    1992 Supra Sunsport. **SOLD** 2k pounds ballast, Surf System, Blue LED's everywhere, decent audio system.


    Tow Rig: 2009 Honda Ridgeline RTL (wife's rig) Other money pits include:1998 BMW M3 Cabriolet, 2000 Jeep Wrangler rock crawler), 1999 Audi A6 Avant, 2005 Kawasaki ZX-6R 636.

  8. #8
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    May 2013
    Location
    Fairfax, va
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    That makes sense once you picture everything going on from the transom on back. That really ties things together. I really can't wait to give this a shot. Unfortunately it will be next spring at this point but it will give me time to think and watch what others are doing.
    2007 XLV Gravity Games
    1,100 in each rear locker
    1,180 in front ski locker
    OJ 1435 prop, 325 EFI Indmar Assult.
    Racks added for surfing and kneeboarding.
    Rack for hydrofoil

  9. #9
    Join Date
    Nov 2008
    Posts
    263

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    Great write-up. Personally, I'm torn between the flow, and a gate like Boonjeepin did. I like my wave when I'm listed, but would like a little longer pocket for more area to play. The convenience of easier driving is also nice. I just haven't seen enough evidence of the flow for LSVs, so leaning towards a gate.
    '13 Mobius LSV
    '05 Mobius LSV - Sold

  10. #10
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    May 2013
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    182

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    I haven't come across any system that improves the pocket specifically. Pocket appears to be a result of front to back weight distribution and more specifically, the setting of the wake plate. At least this is what I have experienced with my gates and it appears that the other versions are experiencing the same. Using less weight in the stern enables you to use less weight in the front.

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