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The Hulk

SURF SCOOP ?

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The Hulk

so i've had this idea, any thoughts, comments?

i think it would offer a lot of flexibility for wake-shaping and more dwn force than the wedge while allowing you to do the following:

1. Use them as a wake-Plate / ride plate

2. use them as Trim Tabs

3. use them for downward force

4. use them for downward force different angles between left/right would list boat

5. front foil may be difficult but could also apply down force as well and help with bow rise and down weight/force

a: front foil could adjust with angle of bow rise digitally to minimize bow rise on start up in cruise or wake modes etc.. (similar to wedge 2 lift setting) this could be tied in for back foils to push down as well until surf speed is hit or cruise mode etc.

anyhow i thought it would be an effective setup with more flexibility, now just need to grab and old beater boat !

attached PDF

Surf Scoop.pdf

Edited by The Hulk

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The Hulk

oh and i apologize for the very crude drawings, it makes sense in my head at least so if you need explaining just ask i could spend more time drawing ... just from years ago and keep thinking about it... thought i'd get some crew feedback.

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twitchee2

I thought about this a few years ago and though it would be a great idea. I am a servo controls engineer so this type of stuff is right up my ally. I think it is a great idea just not sure how feasible it is.

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REW

I thought about using "wedge" like devices for pulling one side of the transom down at a time for surfing. I like the concept to be able to trim the boat in all directions or add surf weight without adding even more weight. The forward foil concept is quite interesting.

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mikeo

My question (for someone with a better engineering background than mine) is what amount of surface area is needed to generate a specific amount of force? I'm sure there is a formula, and my point is that while the concept is great can a "reasonable" sized foil generate enough force to list a boat a surf speed? Reasonable size is to be determined based on engineering figures.

If you have to offset 2000 lbs of flotation/displacement and it takes a 9 cu ft of foil at 10 MPH then it's not practical; If it's offsetting 500 lbs of flotation/displacement with 1 cu ft of foil at 6 MPH then it is practical.*

* I have no background in hydrodynamic engineering and don't claim that these numbers even remotely make sense, I'm just trying to get a point across.

I thought I remembered hearing that the original wedge generated 2000 lbs of down force (ballast replacement) at 20 MPH. It's that kind of engineering numbers that can prove out if the concept is viable. The surf gate is "wake shaping" by moving where the water is, not by changing the overall displacement of the boat like the wedge or ballast does. This solution appears to be changing the displacement of the boat.

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Wayne

I'm still thinking if one could come up with with a towable device that is part inflatable, part ballast bag that generated a surf wave you would not be able to make them fast enough. This would make ANY boat that could generate the thrust to move it a surf boat (inboard, v-drive, I/O or outboard) by "filling" it and attaching it to the 2 D-ring tow points. It puts the rider back from the boat so the whole debate with water enforcement officers and tow rope length could be eliminated. The problem is I haven't had the time to think it through, nor do I have the spare time to develop it. So challenge extended to the inventors on the board forum.

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The Hulk

My question (for someone with a better engineering background than mine) is what amount of surface area is needed to generate a specific amount of force? I'm sure there is a formula, and my point is that while the concept is great can a "reasonable" sized foil generate enough force to list a boat a surf speed? Reasonable size is to be determined based on engineering figures.

If you have to offset 2000 lbs of flotation/displacement and it takes a 9 cu ft of foil at 10 MPH then it's not practical; If it's offsetting 500 lbs of flotation/displacement with 1 cu ft of foil at 6 MPH then it is practical.*

* I have no background in hydrodynamic engineering and don't claim that these numbers even remotely make sense, I'm just trying to get a point across.

I thought I remembered hearing that the original wedge generated 2000 lbs of down force (ballast replacement) at 20 MPH. It's that kind of engineering numbers that can prove out if the concept is viable. The surf gate is "wake shaping" by moving where the water is, not by changing the overall displacement of the boat like the wedge or ballast does. This solution appears to be changing the displacement of the boat.

if the wedge provides as much force as it says at 20mph then i'm guessing its around half at surf speeds or so? got me.

i doubt it would take very much angle whether flat sheet or hydrofoil angled to scoop on one side to really pull the boat down, it seems most people try to list at least several hundred lbs more on one side than the other but that makes driving a little difficult when listed and turning around , so when you slow down and are idling you would not have hardly any force or it could retract like SG , i'm guessing 1-2 Cubic feet would be huge difference for simulated weight and listing.

it would just be nice to easily LIST the boat without actual weight and only at surf speeds

one device i thought might be a neat add-on or built into newer boats would be a bow rise degree reading, i mean you can buy a digital level for like $20-40 in fact ive thought about just sticking one on the side window. The reason is that when we have different numbers of ppl in the boat and or weight set ups sometimes its 1-click up on wedge sometimes its 2 sometimes its 3 to get the wave to be the same and bow rise to be the same, it would be nice to have a digital reading that tells you the angle so you can get it close each time. again a simple digital level stuck to the window would work but i think newer bus should build a bow rise degree reading into the dash somewhere. it would also be nice to have a horizontal one so you could measure LIST angle as well so you could calculate bow rise and listing angles as desired

Edited by The Hulk

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The Hulk

if you just did flat plates to scoop i wonder if there would be spray or not at surf speeds, it would obviously depend on the angle and how deep it is,

they hydrofoil concept would be deeper down in the water and require less angle for the same down force and or less "angle" to make the same forces as a flat plate at angle etc..

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mikeo

if the wedge provides as much force as it says at 20mph then i'm guessing its around half at surf speeds or so? got me.

i doubt it would take very much angle whether flat sheet or hydrofoil angled to scoop on one side to really pull the boat down, it seems most people try to list at least several hundred lbs more on one side than the other but that makes driving a little difficult when listed and turning around , so when you slow down and are idling you would not have hardly any force or it could retract like SG , i'm guessing 1-2 Cubic feet would be huge difference for simulated weight and listing.

it would just be nice to easily LIST the boat without actual weight and only at surf speeds

one device i thought might be a neat add-on or built into newer boats would be a bow rise degree reading, i mean you can buy a digital level for like $20-40 in fact ive thought about just sticking one on the side window. The reason is that when we have different numbers of ppl in the boat and or weight set ups sometimes its 1-click up on wedge sometimes its 2 sometimes its 3 to get the wave to be the same and bow rise to be the same, it would be nice to have a digital reading that tells you the angle so you can get it close each time. again a simple digital level stuck to the window would work but i think newer bus should build a bow rise degree reading into the dash somewhere. it would also be nice to have a horizontal one so you could measure LIST angle as well so you could calculate bow rise and listing angles as desired

Hulk: A controller like this would be perfect:

http://waketouch.com

It's just getting a manufacturer (Malibu) to put it in the boat. With the 7" computer there is enough "horsepower" for the logic, it just needs an accelerometer to sense pitch and yaw.

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Kalamazoo

why dont you simply install two power wedges port & starboard? independently adjusting them will list/unlist as needed, right?

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Bill_AirJunky

The front foil has been tried at least once that I recall. Unfortunately it was already patented & the patent holder was uncooperative with allowing it to be used.

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The Hulk

why dont you simply install two power wedges port & starboard? independently adjusting them will list/unlist as needed, right?

Yes similar but the power wedge needs the foil to pivot IMO

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The Hulk

The front foil has been tried at least once that I recall. Unfortunately it was already patented & the patent holder was uncooperative with allowing it to be used.

Bummer I'm sure there is a way to modify around it

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The Hulk

Hulk: A controller like this would be perfect:

http://waketouch.com

It's just getting a manufacturer (Malibu) to put it in the boat. With the 7" computer there is enough "horsepower" for the logic, it just needs an accelerometer to sense pitch and yaw.

I've seen this a while back but it appears mostly a concept not developed fully? Or no boat mfg has incorporated it yet?

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formulaben

My question (for someone with a better engineering background than mine) is what amount of surface area is needed to generate a specific amount of force? I'm sure there is a formula, and my point is that while the concept is great can a "reasonable" sized foil generate enough force to list a boat a surf speed?

http://www.ajdesigner.com/phpwinglift/wing_lift_equation_force.php#ajscroll

(a coefficient of lift of 1.5-2 is attainable with a cambered foil; density of water is 1000kg/m3 for fresh water)

Per the calculator, it will be 4 square feet at 10mph to get 1000+ pounds of either lift or downforce...depends on foil, aspect ratio and other factors, but that's a conservative number. At 11.5mph 3 sq ft gets you 1500+lbs. Either way, they will be relative big.

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The Hulk

http://www.ajdesigner.com/phpwinglift/wing_lift_equation_force.php#ajscroll

(a coefficient of lift of 1.5-2 is attainable with a cambered foil; density of water is 1000kg/m3 for fresh water)

Per the calculator, it will be 4 square feet at 10mph to get 1000+ pounds of either lift or downforce...depends on foil, aspect ratio and other factors, but that's a conservative number. At 11.5mph 3 sq ft gets you 1500+lbs. Either way, they will be relative big.

formulaben! good info for the lift with a foil/wing, the foils coudl add a decent amount of simulated ballast with much less DRAG than a scoop or wedge...

is there a calculation that can determine the "digging" force of a flat plate at specific angles and mph in water? It might get more complicated trying to calculate the foil's lift at a digging angle. as the foil would create less lift in the digging position so thats why i'm not sure if a foil is worth it or just flat plate that is "digging" s, essentially as mentioned above similar effects of 2 wedges, but my concept also allows you to use them as trim plates or ride plates when the front is pulled up even with the hull.

my "thinking" is that a digging scoop would have a TON more force than a hydrofoils downward Lift, obviously more drag as well. but i think it would be easier than a foil design for mfg. the question would be if you get a rooster tail of water in the surfers face or not? that would probably depend how far below the water level you could deploy them

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The Hulk

basic scoop concept

post-28204-0-68946500-1442011123_thumb.p

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