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jklein

An adjustable wedge

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jklein

Since Malibu came out with two types of foils, one flat and one angled, it begs the question of how might a wedge that had the ability to change the foil shape create new ways to shape the wake not only at boarding speeds, but at surfing speeds too.

I think it's generally accepted that different angles on the wedge will cause more or less downward force and thus hull displacement in the water.

the foil itself would have to be two pieces with a hinge in the center or something similar mounted to the bronze cross beams in a different way to allow for adjustment. Maybe slots with set screws at certain fixed positions would work.

Of course you would also need a way to make the foil rigid once you got it to the angle you wanted. A set of differently angled brackets that recessed into the bottom of the foil with set screws might again work.

This isn't something that you would adjust on the water, but you could "tune" it to your liking and then just leave it or change it depending on how your tastes change.

I wouldn't get too hung up on the mechanical engineering part of the system, that part is likely very doable, and could be made reliable and safe I'm certain.

Just an idea...

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Boomer

Do you mean something like the Session Whale Tale?

Here's their description of it:

This optional adjustable hydrofoil allows positioning from 0 – 12 degrees,

redirecting the prop wash up and applying the transom force downward

for precise wake control. The Whale Tail is switch activated with preset

memory functions. The preset settings can be accessed from a panel

located next to the dash. This allows you to create huge wakes without

excessive amounts of ballast (available as option for both the 22Si and 22Xi).

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Sunsetter95
Do you mean something like the Session Whale Tale?

Here's their description of it:

This optional adjustable hydrofoil allows positioning from 0 – 12 degrees,

redirecting the prop wash up and applying the transom force downward

for precise wake control. The Whale Tail is switch activated with preset

memory functions. The preset settings can be accessed from a panel

located next to the dash. This allows you to create huge wakes without

excessive amounts of ballast (available as option for both the 22Si and 22Xi).

That is very interesting. I wonder what ever happened to this venture?

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mrothwell

If I understand what John is saying, it's not like the Whale Tale. The WT is adjustable on the angle of deflection only. John is looking at changing the shape of the foil from a nearly straight (Wedge vI) to a V shape (Wedge vII). But be able to achieve various angles of "V". This is somewhat intriguing to me as a "tinkerer". Not being a boarder, unless the skiing sux that day, I wouldn't be a good judge of what was good vs what isn't.

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tvano

i still wonder if you reversed the angle of attack (to lift) if the slalom wake would get flatter?

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We bent our wedge on a stump and increased it's angle of attack to the water. The result was a super surfing and boarding wake on a RLXi. I would have kept it like that only it wouldn't fold up und er the swim platform. I wonder if putting some shims between the arms that come down and the wedge plate would do the same thing?

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mrothwell
i still wonder if you reversed the angle of attack (to lift) if the slalom wake would get flatter?

That's the test I would like to try - been thinking about it ever since I got a boat equiped with a Wedge.

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Waterbuggy

Ever try riding a foil (Skyski, Airchair) at 34-36 mph. WHOA! Too much surface area on the wedge blade to make it anywhere near stable at that speed. Hate to think of the stress on the transom too.

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jklein

Isn't that what the scarpa plate does?

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Waterbuggy

No. the SSP is just an extension of the hull with just enough hook to lift the stern higher. It's a trim tab

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motoring

the new power wedge will be adjustable. Not sure how. But they said 400-1200LBS

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brazosvet

Doesn't the Scarpa plate improve the wake for slalom also? It seems that footers and slalom skiers would be looking for similar wakes.

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Are you wanting to improve the wake behind a RLxi? If so, why? If you are talking about improving the slalom wake of a wakesetter then I can understand. Realize this though, anything you do to raise the stern will drop the bow and increase the wetted area of boat. It takes tons more HP to maintain the same top end.

One thing you could do is to put some "hook" on the back of you boat. This is a more permant solution though. You can take body puddy and form a small "hook" or dip at the very back of your boat- .060"-.125". At slow speed that hook doesn't have any authority but, at high speeds it will lift the back end up more.

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jklein

I was just proposing that the inverted "v" aka "^" of the wedge be adjustable from flat "-" to some angle "^".

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brazosvet
Are you wanting to improve the wake behind a RLxi?  If so, why?  If you are talking about improving the slalom wake of a wakesetter then I can understand.  Realize this though, anything you do to raise the stern will drop the bow and increase the wetted area of boat.  It takes tons more HP to maintain the same top end.

One thing you could do is to put some "hook" on the back of you boat.  This is a more permant solution though.  You can take body puddy and form a small "hook" or dip at the very back of your boat- .060"-.125".  At slow speed that hook doesn't have any authority but, at high speeds it will lift the back end up more.

I think the wake behind a RLXi is fine, just was asking what-for about the Scarpa plate.

I don't think that body puddy will be anywhere near my Bu..... I hope.

Edited by brazosvet

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