Designing surf tabs out of auto trim tabs

[trayson]

Very cool. keep us updated.

[kirkman]

Awaiting to see this in action, Im needing a better surf wake also...

[wolff supra21v]

Not real happy this week had a good wave with plenty of push but wanted a little more length. I tried to length the wave by adding additional 400lbs to the nose of the boat and the wave looked real good but lost all its push. I am going to try and change the plates this week. Going to work on two types one to match the Moomba flow and one with a fins on the bottom to hopefully delay the water a little. Hoping to do some testing next weekend.

[icemanftr]

Not real happy this week had a good wave with plenty of push but wanted a little more length. I tried to length the wave by adding additional 400lbs to the nose of the boat and the wave looked real good but lost all its push. I am going to try and change the plates this week. Going to work on two types one to match the Moomba flow and one with a fins on the bottom to hopefully delay the water a little. Hoping to do some testing next weekend.

Any updates since May? Been pondering this Idea myself on my LSV.

[GT Canada]

Well shoot! I read through this whole thread in anticipation of some great results only to see it ends abruptly.

Does anyone have any further info on this? My guess is with the addition of some fins on the bottom of the plate it would have worked great!

[Leebo]

GT - I feel your pain, it’s like reading a great book only to find someone tore out the last 10 pages!

There’s probably more info on WakeGarage.com about retrofitting tabs/gates. Someone pls correct me if I’m wrong but gates are easier to dial in but are harder to install on an LSV hull. Tabs are easier to install, but need lots more ballast and then there’s the question of tab shape/dimensions.

A couple people there have built GSA-like tabs with success but are afraid to share the dimensions bc it’s patented…which is odd bc patents are in the public domain and the violation occurs when you reproduce for commercial gain.

It’s on my list to try to get these done this summer and my plan is to use the patent to get the dimensions- the big assumption is that they are drawn to scale. *some* of the angles are given and one of the dimensions. The text of the patent describes the optimal deployment at 10* but I believe most had better results at 5*

Here’s a link to the patent 9,545,977. If you build it first, pls let me know!!!

[sandm]

leebo,
I don't blame them for not putting stuff out there as so far every boat manuf. AND gsa have caved to lawsuits by 'bu and are paying patent royalties for every set used except skiers choice(afaik theirs is still pending and they haven't given in yet GO SKIERS!!!!) so not sure I'd want to be the little guy on the interwebs tossing out info on this.
I've read that patent before and can't say I remember it giving dimensions, only guides.

[Leebo]

sandm –

I hear ya, but we are talking about the opposite ends of the patent system. You’re referring to the commercial implementation of a patent and I totally agree – that is protected by a patent.

What I am referring to is the sharing of ideas surrounding a patent – ideas are in the public domain. Said differently, talking about the specifics of a patent is not protected, and for good reason. In order to be awarded a patent, the applicant needs to demonstrate their idea is non-obvious and contains no prior art. Sharing of ideas is the whole point of a forum – and talking about those ideas will help clarify whether something is non-obvious and/or help prove there may have been prior art. And as a side benefit to us, we *might* just advance the ball on these ideas and make a better system that isn’t protected by a patent (not holding my breath )

Now, whether you choose to take these ideas and implement them for personal use…that may or may not be protected. So the guys that said “Hey, I built my own GSA tabs” may not have avoided legal problems by saying “ but I can’t share the dimensions.”

As far as dimensions vs. guides, agree that what they give is pretty general, but I understand that’s there to protect someone from changing angles by a degree or two (or dimensions by a few mm) and calling it different (and circumventing the patent protection.)

For specific dimensions, this is what I read/interpreted and would love your feedback:

• They list the end of the tab that mounts to the piano hinge as 17 ¾” with the inner angle as 81˚ and the outer angle as 99˚ (in the patent, column 7, rows 16-18 ).
• Also, the critical part of the GSA tab – the fins at the end (referred to as a “hydro-thruster assembly” or “hydro-thruster diversion fins”) - are all 17˚ from the centerline of the boat and the tab deploys 12˚ from the centerline (column 12, rows 47-54).

Yup, I had to read 1400 lines of the patent to get the info contained in 11 lines… The rest of the dimensions/angles would need to be inferred from the drawings and you have to assume it was drawn to scale.

My guess is that the exact size of the tab is probably not as important as the angle the tab deploys and the angle of the hydro-thrusters (and the venturi effect of the volume change.) The amount the tab deploys is important but I would think you dial that in after adding ballast, and adjusting boat pitch/roll/speed.

THX!

[SONIC]

sandm –

I hear ya, but we are talking about the opposite ends of the patent system. You’re referring to the commercial implementation of a patent and I totally agree – that is protected by a patent.

What I am referring to is the sharing of ideas surrounding a patent – ideas are in the public domain. Said differently, talking about the specifics of a patent is not protected, and for good reason. In order to be awarded a patent, the applicant needs to demonstrate their idea is non-obvious and contains no prior art. Sharing of ideas is the whole point of a forum – and talking about those ideas will help clarify whether something is non-obvious and/or help prove there may have been prior art. And as a side benefit to us, we *might* just advance the ball on these ideas and make a better system that isn’t protected by a patent (not holding my breath )

Now, whether you choose to take these ideas and implement them for personal use…that may or may not be protected. So the guys that said “Hey, I built my own GSA tabs” may not have avoided legal problems by saying “ but I can’t share the dimensions.”

As far as dimensions vs. guides, agree that what they give is pretty general, but I understand that’s there to protect someone from changing angles by a degree or two (or dimensions by a few mm) and calling it different (and circumventing the patent protection.)

For specific dimensions, this is what I read/interpreted and would love your feedback:

• They list the end of the tab that mounts to the piano hinge as 17 ¾” with the inner angle as 81˚ and the outer angle as 99˚ (in the patent, column 7, rows 16-18 ).
• Also, the critical part of the GSA tab – the fins at the end (referred to as a “hydro-thruster assembly” or “hydro-thruster diversion fins”) - are all 17˚ from the centerline of the boat and the tab deploys 12˚ from the centerline (column 12, rows 47-54).

Yup, I had to read 1400 lines of the patent to get the info contained in 11 lines… The rest of the dimensions/angles would need to be inferred from the drawings and you have to assume it was drawn to scale.

My guess is that the exact size of the tab is probably not as important as the angle the tab deploys and the angle of the hydro-thrusters (and the venturi effect of the volume change.) The amount the tab deploys is important but I would think you dial that in after adding ballast, and adjusting boat pitch/roll/speed.

THX!

As one of "those guys"...
IMO if you have the skills to build them you can certainly drive over to a dealer with a tape measure and get some dimensions.
I'm not willing to risk having someone at sue-happy malibu or GSA throw a lawsuit at me, baseless or not.

To me "I built my own tabs" is one lost customer for them (potentially)
"hey entirety of the internet here are the dimensions and the step by step processes to make your own GSA tabs" is a potential loss of a lot of sales and a much bigger deal than "I built my own tabs"

If you're familiar with any type of patent law (or just law in general really) then you know that at the end of the day it has a lot more to do with who has more money and who is going to give up in order to quit hemorrhaging money first vs who is in the right.

If one of them did decide to file a lawsuit you're already out minimum 10k just to have a good lawyer write a response, none of which you're getting back unless you go to court spend 500K+ and win and then get your court costs covered. God forbid you lose, or run out of money somewhere along the line then you're just screwed while 'bu sits back and counts their pandemic profits lol.

To answer some of your questions:

The size is really not that important, people have had success with different sizes, GSA is a one size fits all job which is almost never the right fit for every application.

The correct size depends on your hull and your weight. You want to create just enough lift to cause the correct list angle without lifting so much you negate your ballast.

The deflector wings do create a nice wave but they are not the only way. Tige has moved away from the GSA tabs (likely didn't want to pay royalties to malibu and gsa at the same time after gsa lost their suit to bu) and their new tabs arguably make a better wave then the gsa they replaced, lots of people think so.

Supra swell waves are widely regarded as some of the best and they are using a very simple trim tab with a bend in it that would take 5 minutes to make.
Obviously the hull makes some difference as well but my point of there's a lot of ways to skin a cat and you likely won't go wrong if you wing it and build something that's based on any of the major systems.




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[Leebo]

SONIC -

Thank you for the information. I did not see myself finding a boat w GSA retrofitted and out of the water for me to measure (at least nowhere close to me.)

Agree the fabrication is not the hard part, but to your point “the correct size depends on your hull and your weight.” I was pursuing the GSA size/style bc of the broad range of boats that have been successful with it.

If I understand it correctly, Tige used GSA in 2020 only. Is that right? There’s a dealer a little more than an hour from me. I’m guessing the GSA-style tabs will be obvious vs the newer tabs. THX!