DIY SURFGATE

[stoked 1,039]

So first off, thanks for tuneman for the inspiration for this. I used most of his measurements, but show how I got them (his post is here http://www.centurioncrew.com/index.php/topic/6767-finally-surfgate-on-my-enzo-sv230/?hl=%20swim%20%20platform). Second, I'm not making this for anyone, nor am I selling it (in case malibuers are reading this). This is nothing more than a random assembly of lumber demonstrating fluid dynamics.

 

Materials used:

 

2x12x6

2x3x4

1x2x6

3/4x10x4 plywood

2007 Avy

 

So I didn't use pressure treated lumber, my intention is to use this as a mockup to prove it works, then make something out of plexiglas with some hydraulics. So I went on the cheap for now. I think total lumber cost was like $30. This took me about 3 hours to complete.

 

Okay, to start I needed to get the angle of the hull. tuneman had this as 12° but his boat is an Enzo and I didn't want to just assume mine was the same. So I clamped a piece of wood to a level and stood it on the trailer leaning against the boat using the level to ensure I was straight up and down. I then put my protractor against this combination and ran my finger down between it and the boat to ensure the entire length was equidistant from the boat.

 

This came out to 12° on the button

Next, I needed to know how long the bottom piece should be. The bracket for my swim platform means I don't have a lot to play with underneath. I laid my long piece of wood against the boat and measured from the bracket out. This would be my minimal length at the front. I cut this at 14", the top I made 16".

Next I made the 12° cuts. Since I'm making one for both sides, I did this all at once

Next I measured the space between the two boards to see how thick of a spacer I needed. It came out to 2.5". Which, perfectly enough a 2x3 is actually a 1.5x2.5, so there was no need to cut the spacers down.

I clamped a spacer in and measured how long my support pieces would need to be. tuneman had this at about 9.5", mine came out to 10". Basically I measured from the bottom of the hull to the top of my 2x12.

 

Okay, time to cut the spacers and the support strips. I cut the spacers to 11" since the 2x12s are 11.5" wide. And the support strips I cut to 9". I cut both sides at once, here's what one side looks like

 

Next I screwed a top 2x12 into the spacer

Then I stood the boards up with the spacer on a flat surface so that the angled ends would be in line and I clamped in place

This would be a good time to realize your spacer is on the wrong way and dump your drill bits all over the ground. Have fun getting them back into there proper holders in size order...

This is also a good time for your significant other to come out and ask what you're doing. Argue with her for about 15 minutes how it will clean up the wave and making switching sides effortless. Continue to argue with her that there is no way it is "going to fly off and hit someone in the face". Another good time waster is to spill your drill bits yet again, mumbling to yourself you need to put them in a better spot.

Alrighty, now that we're past all of that, put your piece on your swim platform.

 

Add the support pieces so we can get the angle and final position set

 

At this point for some reason my port side platform retainer was getting in the way, so I relocated it to between the boat and platform. It bent like crazy so I had to bend it back. Also, this will now be hell to remove come winterizing. I didn't have to do the starboard side, don't do it if you don't need to

Okay, now is the time to get the angle. According to tuneman and some articles I've read, 20° is the magic number. So I placed my protractor on the setup and again placed my long piece of wood against the boat. I moved the setup until the wood matched my angle (I set the protractor to 160° for this as it got the angle going in the direction I needed)

 

now that I have my angle, I added spacers that will hold this angle against the swim platform. I neglected to take a photo here, But you'll see them in the later ones.

 

Next I cut my plywood to 20" by 10". The 10" we got earlier in our measurements, the 20" I got from googling around on the malibu specs.

 

 

I then proceeded to mount these to the supports. I cut one end of this board at a 45 degree so that it would sit flush against the boat (we can see that spacer here)

 

Finally, I sacrificed a pair of old jeans to keep from scratching the boat and the swim platform. A positive byproduct is a sweet pair of daisy duke jorts!

 

I just had SeaDek make it for me, and I'm not about to scratch it up. I may also use my router to round all sharp edged corners. I stapled the jeans to anywhere that will touch the fiberglass or the platform top. Be careful not to put staples in where it touches

And that was it!

Some extra angles:

The Surf Gods seem to be blessing this.

 

It's still pretty cold here, but once I get it in the water, hopefully this weekend or next, I'll try to post some pictures of both sides in action.

Edited April 7, 2014 by stoked

[Nick213 583]

How are you keeping them attached?

[Audionly101 39]

After playing with my own vertical tab setup I have a few tips for you. First, your tab is far too high up on the hull. Since your Avy will want a decent amount of list either way you essentially will be forcing that tab up even higher and out of the water. Second, I think you have too much of an angle outward. The first time you drive with it out that far you will notice how hard your engine is working to offset all the extra drag and your boat is going to handle horrible. Give it a try with your setup but I recommend making some adjustments and seeing how they turn out. Good luck!

[stoked 1,039]

Thanks for the tips Audioonly101! From what I saw with all of the Malibus, the tabs go down only to the where the hull meets the bottom. Do you recommend I go past this point? If so, how far? Isn't the point of the tabs to run without list, keeping the ballast and thus the boat exactly even? Do you know what angle you ended up with? I'm going to try and get out this weekend and play with some different angles.

 

@Nick213: I'll run a strap through the eye, around, and back up to it.

[RhuntIII 555]

Stoked,

The Malibus with surf gate are designed to have the rear of the boat weighted equally. Your Avy needs to be keeled over. This would cause the tab on the opposite side to come up out of the water like Audi was saying. I'm thinking a lower tab as well.

 

Get that boat in the water and post up how she does.

[stoked 1,039]

Will do!!

 

I guess I'm not understanding why the Avy needs to be keeled over. In tuneman's videos he did something very similar with equal ballast and it really cleaned up and lengthened the wave. Everything I've read is a level boat.

[RhuntIII 555]

You are now deep in a custom modification project which will require lots of testing and tweaking. I think you on the right track but that Avy's gonna want to lean over to throw a good wave.

[shawndoggy 49]

You are now deep in a custom modification project which will require lots of testing and tweaking. I think you on the right track but that Avy's gonna want to lean over to throw a good wave.

 

so you are saying that surfgate won't work at all and he will have to list the boat? Isn't the whole point of "delayed convergence" (i.e. surfgate/nss/flow) that you DO NOT have to list?

[shawndoggy 49]

Stoked,

The Malibus with surf gate are designed to have the rear of the boat weighted equally. Your Avy needs to be keeled over. This would cause the tab on the opposite side to come up out of the water like Audi was saying. I'm thinking a lower tab as well.

 

Get that boat in the water and post up how she does.

 

There was no design change to the malibus before or after they slapped gates on the back. the 2012 hulls (no surfgate) are exactly the same as 2013 hulls (surfgate).

[WakeDoc 471]

Yes the point would be to sink the boat evenly and for it to work as intended the flap/gate would only be extended on one side. Do you have it set up where you can easily take one side or the other off?

[RhuntIII 555]

There was no design change to the malibus before or after they slapped gates on the back. the 2012 hulls (no surfgate) are exactly the same as 2013 hulls (surfgate).

Shawndoggy,

Lets think about this for a second. Picture the back end of a Malibu and sink her straight down (evenly weighted). Now picture the Avy's back end with a V-Hull list her over on the port side. See the similarities under the water. I know the gates work on the Malibu because I've ridden behind one and I know the listed Avy works because I own one. I think the tabs stoked is working on will work, just need to be deeper in the water. The boat also needs to be listed for optimum wave and the opposite gate deployed. Then when switching from port to starboard riding he will need to chillax with drink, transfer weight and gates for the best results. That is my opinion and I would like to hear Stoked's results after testing.

So what kind of boat do you own?

[shawndoggy 49]

I own an MB, which is shaped a lot more like an Avy at the transom than a 'bu (MB is probably an even more exaggerated V to be honest). I also surf listed and the boat works great. But the fact that the boat surfs well listed doesn't mean it cannot surf well flat too, with some sort of delayed convergence tech.

 

Surely you've seen this thread about an aftermarket/homebrew gate install on an MB, right? http://www.wakeworld.com/forum/showthread.php?t=799766 He runs the boat flat, not listed.

 

What works on a flat hull like a malibu appears to work similarly on a v-hull (MB) and by extension I'd hypothesize it'd work on an avy too.

[stoked 1,039]

That is more inline with all of the forums I've read and research I've done. Everything points to level, albeit with ballast. The mockups are easily removed by undoing one side and hooking the other up, takes about 30 seconds which is way faster than a ballast swap. The end game is to make them out of plexiglas and have them controlled by hydros so the swap can happen in about 3 seconds while under power allowing a surfer to switch sides. And no, I will not be hooking up a horn and turn signals like the new bu's...

 

I hope to get out this weekend to do some testing and take some videos. I'll post results here.

[RhuntIII 555]

I own an MB, which is shaped a lot more like an Avy at the transom than a 'bu (MB is probably an even more exaggerated V to be honest). I also surf listed and the boat works great. But the fact that the boat surfs well listed doesn't mean it cannot surf well flat too, with some sort of delayed convergence tech.

 

Surely you've seen this thread about an aftermarket/homebrew gate install on an MB, right? http://www.wakeworld.com/forum/showthread.php?t=799766 He runs the boat flat, not listed.

 

What works on a flat hull like a malibu appears to work similarly on a v-hull (MB) and by extension I'd hypothesize it'd work on an avy too.

I have not seen that thread, very impressive. Good find.

[Audionly101 39]

That MB on wakeworld is exactly how my setup is as well. I still have not had the guts to mount it on the hull so it is currently on some ugly wood blocking. My Elite V can run level but the wave is better with a fair amount of list. Too much list and the tab comes out of the water sometimes and the whole wave just turns into a mess for some reason that I have not figured out even with the tab in the water. For the most part I still prefer my ballast only wave but the adjustability of having the tabs works great to shape your wave for different conditions, weights, riders and boards.

[adambomb2000 35]

To add one more lil piece of info to the puzzle...check out this article regarding lake tests of various boats with "surfgates" from Wake 9:

 

http://wake9.com/community/content.php

[mancho 85]

That was a good read AdamB... I also liked the boat and surf porn link at bottom of article that had it all.

 

I feel slightly more educated. I saw a red centurion hiding on the ramp... but did I miss the write up??

[tuneman 6]

Hey Stoked, thanks for the recognition! It's been a while since I've been on the forum. Got distracted with snowmobiling. Gotta play year round, ya know.

 

Nice job on those gates. I haven't progressed beyond what you've got, but I do have some good findings:

 

- The wood swells when wet, so make certain that you have a small gap where it slides onto your platform or it'll be tough to get back off.

- I've found the best wave is to list the boat, not weight it evenly:

Even weight will flatten the wave, nice for skim but no steep kick for surf

The boat works waaaay to hard to haul around all that unnecessary ballast. You'll go thru about twice the gas with even weight.

- your tab isn't up too high, it's just fine. Even the opposite side is low in the water when weighted and listed.

 

I hope to get Lenco actuated gates on this year, but it's lower on the list of upgrades. I highly recommend the gates, however.

[stoked 1,039]

Okay everyone, just got back from the trial runs! My friend Damien was kind enough to get in the 54 degree water with me. He lost half a thumb to wake surfing acouple of years back, pro-tip DO NOT coil the rope!! Also, we're regular surfers and spend a chunk of the winter out of the country surfing, so he's a little rusty on the little wake surf board, so don't expect anything crazy in the videos.:

 

Here's my variables:

 

10.5 speed

8-10feet deep (I'm on the Chesapeake Bay, this is about as deep as we can get with flat water)

My ballast: 250 Stock Center, 750 Port, 750 Starboard, 150 Brick on the platform.

 

So here are the different videos, some of you may watch them and and say "big whoop, those waves suck". Please keep in mind we're in 8ft of water. we have never been able to surf the darkside, and it's pretty rough on the regular side. I'm very very stoked to get this to the lake in about a month and a half to see what it will really do in deep water. I'll most likely have the permanent setup by then!

 

Here are the videos!

 

250 lbs center, 750lbs port, 150 lbs Brick on the platform, no SURFGATE:

So you can see, not so good in the bay

 

250 lbs center, 750lbs port, 150 lbs Brick on the platform, with SURFGATE:

We see the same kink tuneman saw, but if you watch the first again, its there too. Overall WAY BETTER! Cleaned up the wake, stood the wall up a bit

Edited October 14, 2015 by WakeDoc

[stoked 1,039]

Looks like I can only do 2 yourtube videos per post, so breaking it up:

 

Here is Damien riding heelside, this is the best we've ever seen

250 lbs center, 750lbs port, 750lbs starboard, 150 lbs Brick on the platform, with SURFGATE:

This was sick. The wave was so large it was getting a barrel at the end. This was huge for only 8 feet of water! Hands down the best wave we saw for the day