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 PostPosted: January 9th, 2014, 8:52 pm   
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good points Dave...as we agree on the weight forward of the CG and yes no two boats alike...at the speed you guys are already pushing these V's I would be pretty happy...but yes rolling would be nervey at speed... but I think is also a function of the aero ....;)

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 PostPosted: January 9th, 2014, 9:19 pm   
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Hey Anthony hope the family is doing well! I hope to do some boating together next year. Been Way too long.

IMO ....
Yes aerodynamics are a significant contributor to handling at the speeds these guys are talking about, however the significant foot pounds being applied at 100mph+, it takes a lot more than some weight distribution to correct. Now we're talking about moving the CG, typically forward to have the boat less sensitive to lift or reducing/changing the pad surface area/shape or reducing the tunnel lift(for MVP/Tunnels). All of which are significant boat changes, which for lake fun I'd rule out.

If the lift is off balance due to a aerodynamic characteristic of the boat (pushing to one side) very little can be done, but since most boats are aerodynamically symmetrical for our purposes "static boat balance" more often than not will address the issue.

There are exceptions:
An example, on my STV, my rear openings for the rigging are open on both sides. An experienced MODVP racer I know used to have a problem near 100 where his STV would drag the left side sponson due to the pressure of the left rear being higher then the right, due to the 3 inch hole,for the rigging on the right.

Now this is for a light boat with one person and no interior. Soon as you start adding weight near the CG the effects of air pressure like this become less significant toward the overall balance of the boat.

The closer you get to the edge the more the little things matter. Sounds like my marriage!

Man the game is terrible tonight if I typed this much

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 PostPosted: January 9th, 2014, 9:58 pm   
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MOTOboat wrote:

Cost beer! We'll actually I need some help building a dock this summer :)


count me in!! ;)

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 PostPosted: January 10th, 2014, 8:48 pm   
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Dave... yes I agree...Its been too long....hopefully in 2014...all good here...just VERY busy ;)

Yes I completely agree that these boats are at thier threshold already and that adding the weight for ballast may not correct the lean-to...

I completely agree with working on the CG...however lets not forget that the MVP hull has a dynamic CG...which is why they all porpoise to get over the hump in the 70mph range...the CG starts at the transom and then once it burps the air out the tunnel the CG is basically at the seat of your pants....so for the V guys thats what I would do to correct the CG...adding weight mid-ship and fore.... however again that only assists the CG and most likely won't overcome the aero lean-to....but certainly a boat with the CG more forward will be a much nicer ride and more freindly on deceleration than the CG bang on the transom

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 PostPosted: January 10th, 2014, 8:59 pm   
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time to get some spoilers boys ;) :mrgreen:

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 PostPosted: January 10th, 2014, 9:03 pm   
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JC bolt this sucker to your deck. :mrgreen:

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 PostPosted: January 10th, 2014, 9:50 pm   
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AnthonySS wrote:
Yes I completely agree that these boats are at thier threshold already and that adding the weight for ballast may not correct the lean-to… I completely agree with working on the CG...however lets not forget that the MVP hull has a dynamic CG...which is why they all porpoise to get over the hump in the 70mph range...the CG starts at the transom and then once it burps the air out the tunnel the CG is basically at the seat of your pants....so for the V guys thats what I would do to correct the CG...adding weight mid-ship and fore.... however again that only assists the CG and most likely won't overcome the aero lean-to....but certainly a boat with the CG more forward will be a much nicer ride and more freindly on deceleration than the CG bang on the transom


Thinking along the same line for my particular application… I would like too try moving a couple things forward. A side steer V bottom lake boat has its challenges and needs the movable weight… i.e. running solo or with a boat full…
Would be real easy if were a centre steer with tandem seating. As far as the aero lean I don't know but that's what the steering wheel is for ;)lol. Just a lot more fun to run that a modified tunnel lake boat whether you are going 50mph or a 110 mph… jmo

Keep the info coming …always need the input and advice from informative knowledgeable guys like yourselves... God knows we can all use a bit… thank you... Great post's Boyz :mrgreen:

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 PostPosted: January 11th, 2014, 9:17 am   
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I was just thinking that my battery is I the center of my boat right now... I could relocate it to help.


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 PostPosted: January 11th, 2014, 9:54 am   
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OneCycle wrote:
I was just thinking that my battery is I the center of my boat right now... I could relocate it to help.


that may not be enough JC ,

what i wonder, is there any deck or hull mods we can do to correct this high speed lean, without bothering the low speed handling characteristics.

:idea:

look at an f1 hull, tons of little adjustable wings all over it to keep it flying properly. im sure we can take advantage of wind pressure to help us, even tho out boats dont ride on air. ther is tons of pressure flying by not being used.

what about a small torque tab on the starboard side pad. ?

im just brain storming, hopefully Dave and Anthonyss can help sort out my confusion. :lol:

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 PostPosted: January 11th, 2014, 1:14 pm   
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So the first event at my cottage this summer will be a the "Ballast Blast", get off your rocker. Hum that could go bad!

Bring your two sets of 1,2 and 5lbs soft weights and industrial Velcro and we'll figure out where it needs to go. The principals are the same for vbottom, modv and tunnel. The difference is where you put the weight. I have the most experience, with tunnels then MODv.

The variables on a vbottom are fewer so we'll have it figured out in an afternoon before beer.

Yes the "CG" moving forward is a redistribution of the balance point since a tunnel boat has pressure building (lift) in the stern, more prominently that non tunnels(it's a more significant variable). If you drew a force diagram of the boats CG(mass and gravitational centre point) it would be the same, the difference is a new force (lift) which is variable with speed has been added to the stern. In the end yes this needs to be considered when balancing the boat.

I agree the boats balance centre of force moves forward. Since gravity is constant and the boats weight is constant thus the CG does not change, but now I'm being an ass and playing with words, It's winter I'm bored ..:)

Tunnels don't really transition through a hump, they are a step function, they are packing air or not.


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