why does my euro bounce at 70 mph?

[MARCSOTO]

i have a 93 euro with a 260 and im runing an et 30...... what is happening that the boat starts to bounce around 65 or 70???

[stokernick]

nature of the beast,just drive through it!

[MARCSOTO]

so its not trim???

[chrislopez1313]

Its 0 to 100+ forget everthing inbetween.
A slight porpoise is normal, Mine did it too.
Chris

[Dave Strong]

All tunnels have a point where this happens, some more pronounced than others. Go to www.aeromarineresearch.com and look for articals written for magazines, I believe Jim did one for Hot Boat mag. His book Tunnelboat design is worth getting and explains it well.


Dave

[Speed Jr.]

In short; Bernoulli's principle's. If you understand these principle's, you will understand WHY your boat or anything on water does what it does. I find it amazing that this 18th century mathematician understood fluid dynamics that boat companies dont care to study.....When people start building boats according to these principle's and Bernoulli's equation, these bad characteristics will dissappear and boats will be going a lot faster.

Jr.

[STV_Keith]

Basically this is the point at which your boat is generating enough lift to start to free the boat up, but as soon as it comes up, it spills the air from the tunnels and now doesn't have enough lift anymore, to keep it flying. Depending on the weight of the boat and the weight in the boat, this will shift around by up to 10mph. Pointing into or away from the wind will affect it too. As mentioned, drive faster or slower to avoid it, but it will always be there if you try to cruise or slowly accelerate through that range.

[STV_Keith]

In short; Bernoulli's principle's. If you understand these principle's, you will understand WHY your boat or anything on water does what it does. I find it amazing that this 18th century mathematician understood fluid dynamics that boat companies dont care to study.....When people start building boats according to these principle's and Bernoulli's equation, these bad characteristics will dissappear and boats will be going a lot faster.
Jr.

Your post infers that the STV isn't properly designed - is that what you meant to convey? The STV design is one of the most stable, high performance pleasure boat designs you can step into. I'm not aware of any other Mod VP style hull that has gone as fast as an STV (please, someone correct me if I'm wrong here) - 151.5mph on GPS in a 18'6" long boat. WOW.

[Speed Jr.]

No, Im conveying that the reason it bounces is very simple and can be explained. Thats all. It can be corrected. Not a big deal. Dont be so defensive, doesnt matter if an STV is designed wrong or right. It is ignorant to think it cant be improved on, cause eventually it will. I put that post up for someone who really wants to educate themselves to truly understand fluid dynamics. Sorry you took it your way.

Jr.

[Dave Strong]

No, Im conveying that the reason it bounces is very simple and can be explained. Thats all. It can be corrected. Not a big deal. Dont be so defensive, doesnt matter if an STV is designed wrong or right. It is ignorant to think it cant be improved on, cause eventually it will. I put that post up for someone who really wants to educate themselves to truly understand fluid dynamics. Sorry you took it your way.

Jr.

It will always be there, there is way more than just hydrodynamics causing the hop. Aerodynamics as Keith said gearcase drag, weight ballance, etc. Just be glad it happens at 65-75mph and not 95-100mph.

Dave

[Speed Jr.]

It will always be there

Im sorry you feel this way. I never said anything about hydrodynamics.

MARCSOTO,

You asked "what is happening" referring to the bounce you are experience. It is easily explained according to these fluid dynamic principles. PM me your phone # and I will gladly read then explain to you these principles. Knowledge is power. I personally dont accept the "Nature of the beast" answer. Thats not an explaination. Does it do it? Yes it does. Can it be explained? Yes. It can be explained in books from the 1730's. Im not trying to offend anyone here, which always seems to happen when explaining something people dont understand.

Jr.

[Dave Strong]

You may change it some but it will always be there just the facts of life all of them do it.

Dave

[Dave Strong]

Im sorry you feel this way. I never said anything about hydrodynamics.

MARCSOTO,

You asked "what is happening" referring to the bounce you are experience. It is easily explained according to these fluid dynamic principles. PM me your phone # and I will gladly read then explain to you these principles. Knowledge is power. I personally dont accept the "Nature of the beast" answer. Thats not an explaination. Does it do it? Yes it does. Can it be explained? Yes. It can be explained in books from the 1730's. Im not trying to offend anyone here, which always seems to happen when explaining something people dont understand.

Jr.

Go to www.aeromarineresearch.com get a reprint of the artical from Hot Boat called "HUMP zone", think you will find it an intresting read.


Dave

[MARCSOTO]

What I'm worried about is blowing over. I don't have a trim gauge and just didn't know if it was on the point of it happening. What speed will the boat be in the "blowover zone", thanks guys.

[FrenchPhil]

Download the STV Euro report on http://www.aeromarineresearch.com/