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Bimini for better wake?


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Has anyone ever heard of the theory that if you have the bimini up that it creates lift at slalom speeds therefore producing a smaller wake? I don't really buy it but would be interested to see what other people think.

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Has anyone ever heard of the theory that if you have the bimini up that it creates lift at slalom speeds therefore producing a smaller wake? I don't really buy it but would be interested to see what other people think.

In theory, the bimini could create some lift. It is an airfoil.

The challenge would be tuning it so that it created the effect that you wanted.

Depending on the angle of attack and air flow around the cover (it would act like a wing), it could either push the front of the boat down or push the back of the boat down. Think of a spoiler on an Indy car.

However, I think since it is a soft material and will flex with the air, that you could not get a noticeable effect.

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No, not really.

If the whole wing is 8 feet in span and has a reasonable chord length of 1

foot, resulting in a total wing area of 8 sq ft, then you could expect to get

about 26 pounds of lift (at a reasonable lift coefficient of 0.8) at 40 mph.

If the chord length was lengthened the drag would overcome the lift by leaps and bounds.

With 3 identical boats in the same water and temperature, you'll find a closed bow is 1 mph faster than the open bow (Response to RLX), and adding a Bimini will slow it another 1 mph.

On the other hand -

Since water is about 815 times more

dense than air, you'll get 815 times more lift (and 815 times more drag, more

or less).

If you want a couple hundred pounds of lift with the same conditions, then you

can use the same hydrofoil, but with much less angle of attack. You'll have

to experiment here. A hydrofoil that is too big will make the lift very

sensitive to angle of attack changes, and thus hard to control smoothly. If

it's too small you'll need a large angle of attack, resulting in large drag.

And of course, a hydrofoil will disturb the wake. In the late 80's early 90's a company tried a foil on the leading tracking fin with high hopes. The problem was none of them thought about the direction of lift is 90 degrees to the foil. As soon as the skier pulled hard to the side and the boat tilted every so slightly, any lift generated was now pushing the boat that way. It was a driving nightmare trying to overcome the force of the foil.

Peter

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If a Bimini can produce a better wake because of lift than an elephant can use its ears to fly. Just my opinion. Biggrin.gif

I saw a post about this on a Mastercraft forum. Just goes to show that those guys are smokin something!

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Has anyone ever heard of the theory that if you have the bimini up that it creates lift at slalom speeds therefore producing a smaller wake? I don't really buy it but would be interested to see what other people think.

you should have a pretty good wake already with a 20' sunscape. A better wake can be had by ensuring only 3 skinny people are on the boat for ski runs (well 2 in th boat, 1 in the water), never have more fuel in the boat than you need for the ski runs, no extra gear, no tower and hope you have the diamond hull.

seriously, get a bimini for the shade, not for the lift.

Edited by Cervelo
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you should have a pretty good wake already with a 20' sunscape. A better wake can be had by ensuring only 3 skinny people are on the boat for ski runs (well 2 in th boat, 1 in the water), never have more fuel in the boat than you need for the ski runs, no extra gear, no tower and hope you have the diamond hull.

seriously, get a bimini for the shade, not for the lift.

Exactly, if you want the best slalom wake, don't add the weight of a tower to hold your airfoil bimini.

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Exactly, if you want the best slalom wake, don't add the weight of a tower to hold your airfoil bimini.

I actually never thought the bimini would really create any kind of lift I was just interested if anybody had heard anything like that. My sunscape does have a great slalom wake even with a tower and v-drive. One guy i ski with has a DD moomba and he likes mine much better. I would have bought a response but the wife said no way to "that great big thing in the middle of the boat". I have to say i am actually glad she did because i love the room and the wake.

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Start by buying one of these and just tweak it to do what you want.

It should totally work dude. Whistling.gif

That's the most ridiculous thing I've seen in quite a while. I'm an aeronautical engineer and pilot - the speed required to make that have any noticeable effect would be much faster than the boat can go. You'd be better off sealing the front top of the tower with 3/8 to 1/2 Plexiglas sheet creating a wind dam - of course it would look stupid and it would still be debatable how much real effect it would have - perhaps if you were heading straight into a 100 mph headwind. I hope they don't sell many of those or at least if they do it's all Mastercraft owners. Biggrin.gif

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It looks like that tower mounted foil weighs about 2000 lbs. I believe them when they say it makes the wake bigger, just not for any of the reasons they probably claim.

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Yeah,

I think if you just mount it backwards, it should give you lots of lift. Surprised.gif

Wow, that is possibly the most horrible thing I've ever seen on a boat. And the best part, they actually do have it mounted backwards!

"Radical styling"

"A fat wake and good looks, what more could you ask for?"

Is this a SNL skit or something? Really, am I missing something here?

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Wow, that is possibly the most horrible thing I've ever seen on a boat. And the best part, they actually do have it mounted backwards!

"Radical styling"

"A fat wake and good looks, what more could you ask for?"

Is this a SNL skit or something? Really, am I missing something here?

Totally agree. That thing would add more ballast weight than "downforce". Do people really thing an airfoil will work effectively to create a wake at 20 mph while wakeboarding? Better yet 10mph while surfing?!?!Crazy.gifROFL.gif

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It looks like that tower mounted foil weighs about 2000 lbs. I believe them when they say it makes the wake bigger, just not for any of the reasons they probably claim.

2000 lbs? Where does it say that? I'd be surprised if there was a tower made that was rated for anywhere close to that kind of weight. Are you sure they're not claiming 2k lbs of downforce?

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Well,

I've noticed that when I tow my boat (5 hrs. ~150 miles one way) that if I leave the wedge down, I get a lot less tongue weight. I wonder if I mounted this foil on the tower backwards (like I said earlier) if it would create 2K# of uplift. If I keep my transom tiedowns on like M-dude says, that should virtually eliminate half the weight of my boat. Then, I should get like double the gas mileage. Like 8 miles to the gallon instead of 4.

Oh baby, I'm gonna order one right now!

Heck with the fuel savings, it'll pay for itself in my first season of only taking my boat out twice because I'll be towing it 20 hrs. round trip just to do so. I wonder how they'll ship it? Have a big rig pull up in front of my house, driver gets out, climbs on cab of his truck, unbolts his wing, hands it to me?

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Have a big rig pull up in front of my house, driver gets out, climbs on cab of his truck, unbolts his wing, hands it to me?

Be sure to check for smushed bugs before you bolt it to your 'bu.

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2000 lbs? Where does it say that? I'd be surprised if there was a tower made that was rated for anywhere close to that kind of weight. Are you sure they're not claiming 2k lbs of downforce?

hey wg, your new avatar, what is it and is the white part supposed to look like a 6 and is the red part supposed to look, you know, like a 9??

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