Surf Tabs - Trim Tabs to enhance Surf Wake

[brad]

Visited the Boat Show the last couple of years and looked at the Surf Tabs/Trim Tabs that most manufacturers are putting on their wake/surf boats.

Has anyone explored the options to add this concept to their Epic?

[tryme]

no I have not. but as I walk around the boat show I look at the other ski boat, nautique, mastercraft, Moomba,  and then I realize how crazy expensive they are.  until I go to the higher end pontoons.  with 300hp outboards and granite top bars selling for 95,000.  who has that much disposable income?

[JIMBO]

i am planning on putting these on my s22 soon. I figure ill mount them on 5" x 5" angle brackets that fit in the notch of our sterns secured by bolts through the floor of the trunk.

here are a bunch of threads all in one place about other guys doing retro fit surf gates

http://www.themalibucrew.com/forums/index.php?/topic/42305-the-diy-surf-gate-thread/

here are the lenco actuators to control the gates

http://www.ebay.com/itm/Lenco-9-x-12-Standard-Trim-Tab-Kit-w-Standard-Tactile-Switch-Kit-12V-15104-102-/191505086922?pt=LH_DefaultDomain_0&hash=item2c9697b9ca

the actual part number for the malibu ones they use on 2014 and newer boats (3 seconds to switch sides instead of 7) is

 15129-001, 102F Actuator

[brad]

Thanks for the links.  NSS, Surfgate or trim tabs.  Curious which approach works best with our hulls.  Keep us posted on your results.

[Supraman]

Very timely post... I've been thinking about the same thing... Any ideas? I'm considering building a new swimdeck this spring. I wonder if I can incorporate some sort of manual surf system into the new platform?

[cyclone]

Unless you have a machine shop or something it seems like tabs would be a better idea, they aren't super expensive.

Has anybody put tabs on an Epic? When I thought about it years ago I remember coming to the conclusion that the transom shape is weird, wasn't sure if there was room for the actuator. I should do a search

[JIMBO]

i had an idea to unscrew the swim platform rails from the underside of the trunk (notch in our transom)and replace them with one big piece of metal scribed the the same shape and size as the underside of the trunk (width of the boat long and 11inches wide which is the trunk overhang)

anyone follow me ?

this will enable me to weld on brackets and hinges and actuator mounts for "test surf tabs"

once i am happy with the performance i can use the metal for lower profile brackets ill bolt to the transom permanently and also replace the swim grid.

has anyone ever unscrewed these rails before ? I'm assuming they are machine bolts threaded into a receiver bracket encapsulated in the trunk floor fibreglass. i.e. the bumped out thicker area where they are mounted.

i know the swim deck is meant for vertical force and not horizontal pressure of about 300 lbs max from the side but tons of guys with other similar boats are mounting temp wood surfgates to their swim grids for the same reason with no problems.

comments and input please

brad and supraman , have you guys been working on anything ?

[brad]

I'm still just in the brainstorming stage, no prototypes begun as of yet.

I like your idea but don't have any feel for the removing the rails.  Others may have input here.

Keep us posted

[toyotafreak]

Jimbo, you got me looking yesterday, and believe it or not 'prototyped' something out of cardboard last night.

Findings:
 - All that reading says either NSS or gates make a really big difference by allowing you to weight less, not tilt the boat with weight, and weight more aft than before (which is great for us because our trunk is huge and out of the way).
 - NSS style appealed most to me, but won't work because we've got so little space under the step (doubt even six inches at the side).
 - Gates would have to extend well above the level of the swimstep to be useful considering the waterline is so high on our boats when even modestly weighted.
 - Gates mo betta solution for us.
 - There are manual, electrical, and automatic approaches out there for deployment.
 
Below is a graphic that shows what I was thinking.

The coolest thing is that I think we could fab a mount that picks up existing through holes. You'd remove the tow eye and the swim step mount from the hull and slide in a sheet that extends up the back to the tow eye and warps underneath to the swim step mounts, and itself mounts the vertical pivot for the gate. Due to the way the hull's done in those two areas, the mount would only touch glass in those two very local areas. Reinstall the tow eye and swim step mount.

Originally thinking the mount could be stamped stainless sheet that's bent into shape, then have the pivot welded or bolted on. There's a need for some reinforcement, but not much. Perhaps the same for the gate, but not worried too much about its construction.

Note there is a 'leading edge extension' on the gate under the step. Not sure how far forward we'd need to extend that, but my thought was it at the very least needs to cover the outlet of the lengthwise steps under the transon step (something like 8 inches in fro the side of the upper hull). Puts more/different stress on the pivot and bracket, but reduces the actuation force. The pressure from the flow on the gate forward of the pivot pushes the gate aft of the pivot into the flow passing the side of the boat.

Regarding actuation...I hear you really like to have them retract for picking up the rider if you can. This leads guys towards actuators and even speed-based automation and automatic deployment. I keep coming back to the concept of car parking brake handles and pedals, where you press them down (or pull them in old Toyota fashion), and there's ratchet function that allows you to stop and hold at different depths. To release, you fully depress (pedal) or rotate (handle) or press the button (lever) to release. A sheathed cable run from there through the hull in the back to the gates. Gates themselves spring loaded to return to inboard stowed position if cable's release (or broken).

Would obviously need to play with the pivot angle (how much lift, if any, in the angle), gate height, length, deployment angle and of course boat weight & balance.

The other bummer is I don't think there's a way around having to chop the swim step. I really really don't want to do that. I read that an awash swim step causes loss of 'push', not just shape. Lots of options, including dudes making their own replacement ones out of starboard, etc. That's 12 screws to remove the teak and install a surf deck.

[toyotafreak]

Didn't show bracket in bottom right pic.

Bottom left shows gates stowed and extended.

Pivot looks great right at the forward corner of the stock swim step.

[brad]

Derek, great ideas and prototype drawings!

[JIMBO]

once i have made the bracket i want to make a few different types on interchangeable tabs to try all in one outing. With a go pro mounted to my tower i can compare waves later and share with you guys.

i like your idea of an upward angle at the end of the bracket to incorporate the tie down eyes for added strength

the gates should be about 12inches high by 22 inches long and deploy out at 22 degrees

lenco 102s are 4.25 inch stroke and are what malibu uses. my plan is to have them on standard stroke indicating trim tab rocker switches i can play with at will and will be manualy controlled

the new 2014 and 2015 malibus have faster actuators I'm working on sourcing that will enable jumping the wake and surfing both sides with a transition time of around 3 seconds opposed to 7-8 but cost about 370 each !!!!

less weight + even boat + larger surf zone + further back surf zone = awesome

i have plans to mount a wedge that will equal 1300 lbs of ballast to the same bracket as well .

[toyotafreak]

So sick! Git er done!

[cyclone]

I know a guy with a machine shop that restores B17's and P40's. He was machining a ball gun turret base last time I visited. He can make anything out of aluminum, probably be glad to do it.

[wakejunky]

Hi All,

It's been a couple years and I told myself to stay off the forum now that I'm not an epic owner anymore, but reading through this topic made me feel like my experience may help. Its just my opinion, you can disregard it if you like. I've owned an epic e22 and the sx, I've done more modifications than I care to explain. I've now owned a 2014 Axis A22 with surfgate and manual (floating ) wedge.

I love projects but please consider this, there are some assumptions in these posts and some grossly inaccuracies.

surfgate does not allow you to weight less- in fact it requires much more!!! as you have to weigh both sides evenly. the weight on the opposite side does not help its simply there for when you switch sides and that side needs to be weighted. Not sure where you read this but I would recommend doing more research. Don't look for opinion that back up what you want to do, you can always find someone who thinks the opposite of 99% of people. Look for the overall feedback.

the wedge - does NOT equal 1000 or 1300 lbs. of ballast. no matter what a dealer may tell you. It simply shapes the wake or wave.

 no wedge = rampy transition,
 wedge = peak at the top of rampy transition.

 The wedge WILL create drag, lots of it. maybe 1000 lbs. of drag. which will keep the engine from getting on plane.

2014 proved to be interesting year for Malibu, axis  with surfgate and wedge and surfing. The crazy amount of weight needed to make surfgate work combined with the wedge to properly shape the wave to your liking created a huge demand on the engine. Most people who bought the 350 hp/ 380ft lbs torque engine had to buy the most aggressive prop they could. And that was not at elevation. Most buyers who found out about this started ordering the ls3 corvette engine option inorder to get the performance needed, some even had to prop the crap out of it( especially at elevation).
This led to two things in 2015 axis switched from indmar to pcm and adopted a super aggressive trans 1.75 to 1 instead of the 1.5 to 1 indmar used. (this is helping power issues) Malibu stuck with indmar and redesigned the wedge to position in a way that lifted the boat to get it on plane, then it moves to a neutral or downforce position once on plan. This has been a great improvement also.

You may disagree with me and that is fine but the epic engine will never produce the torque/power needed to make this work. I know even I used to  love the lexus engine but, its EFFICIENCY was outdated back in 2007 when indmar and the rest of the industry adopted catalyst and o2 sensors for feedback it greatly improved their fuel economy I saw no difference in fuel consumption between my sx with 2000 pounds of ballast and my axis with 3000 pounds of ballast (not using wedge , for wakeboarding)not to mention the huge increase in torque and power.  It is what it is, the lexus engine lacks torque and honestly so does my 2014 axis with first engine upgrade and the 1.5 to 1 trans. Mine struggles to surf and wake board when heavily weighted. I will be upgrading my prop. My sx had the 2nd most aggressive prop on it (I think ryan upgrade to the most aggressive because he is running on Tahoe with super high elevation). I had even played with the idea of supercharging my sx (yes its possible , but its not simply bolt on)

If your going to attempt this I would highly recommend building a "poor gate" as it called. its manual, doesn't cost  much and will prove what your wave will look like and if the engine will handle it. Please don't spend thousands of dollars and countless hours without a proven outcome.

check out this link for lots of info on poor gates, lots of examples and one guy even started his own company building them
http://www.axiswakeboardboats.com/viewtopic.php?f=16&t=1997

Im not posting to pimp axis or bash Toyota. Every boat has different areas they excel in. just make sure the boat can handle your needs. Don't buy a 3/4 ton diesel truck to drag race Honda's. don't buy a Honda and think it will pull your 40 ft toy hauler.