Definition of Planing

Even in physics the experts dont get it right or explain properly.. Magnetisim and centrifugal force are similar and not really a force but are an " infulence".

 

Do you have anything to back up your claim that magnetism is an "influence". I have not seen any other reference, anytime in history, that says that. All data up to now shows magnetism to be one of the forces. However, I am open to new information.

 

Wow Tom, where did that come from? Details please.

 

Didn't you see the press release?

The force part of centrifugal force has been deemed an "infulence".

It's an outrage really.

I've heard they're considering reclassifying the force of gravity as well!

 

They already have, it is bent space.

PS do you have to be called Tom to join in?

Regarding this thread, I am none the wiser ..........but better informed.

 

So I guess there's nothing left to be said about planing.

 

It will soon be according to Stephen Hawkings. The unifying theory that will supercede Eintein's theory of relativity.

http://ph.she.yahoo.com/video/whoknew-unifying-theoru-060000128.html

 

Well, I have my own theory...

 

And i have mine that this thread is never going to end and just ramble on and on like coronation street going no where and about as exciting as watching cow dung dry in the winter sun !!

 

Things like this usually happen because someone is anxious to get their name in the news. Fortunately, physics remains physics and we can go on calling things the same as always with no ill effects. Have to say that "influence" sounds wimpy compared to "force", as in, the wrestler influenced his opponent out of the ring.

Having just finished "The Social Conquest of the Earth" by Wilson, I am well prepared for more of this stuff.

 

I think we should get this thread back to planing. It is a concept we all use everyday. A definition would be hugely helpful. Those who think it is a waste of time, please refrain from posting; it is just negative.

 

How about........"a boat is planing if its wetted hull area decreases with speed increases" But I'm sure someone will cite, e.g., a catamaran flying a hull, or other exceptions !

 

I think some of us don't think consider that an exact definition of planing is of any use other than possibly for legal matters. That probably accounts for much of the OT stuff and what you are calling negative. As for me, I use the point where 50% of the static displacement is lift and 50% is buoyancy as an arbitrary "definition" of the transition point between semi-displacement and planing. Probably impossible to determine in a typical dynamic case but that is OK with me. I don't need to know it anyway to design a boat that operates in that range.

 

your math formula than is:

begin
lift + bouyancy = boatwight
----> boatwight - buoyance = lift
if bouyance < lift than boat is planing !
end

boatwight is known we need the exact value of the bouyance to calculate the lift, but bouyance is known only in the case speed=zero (bouyance=boatwight)

the first question is: what is the bouyance if boat is moving?
-A will you take the free (far away-) surface as reference for the bouyance under the boat?
or
-B is it more correct to look at the high of the bow-waves near the hull?

I tend to B but did this mean near the stern is no bouyance under that part of the hull? because the water close behind has the same level as the stern if the boat is moving fast....

as longer I think about this simple question as much more shaky is the ground for me........ if we messure the pressure under any place under a moving boat can we definitiv deside this part of the pressure is static and that part is dynamic?, can we decide what is the reason of the pressure? or can we only messure the sum of static- and dynamic-pressure and maybe not decide if lift or bouance is the higher part at this point under a fast moving boat

 

I know, I know...

It's when the engine speeds up dramatically, my hair flies back and the wind begins to howl in my ears.

Ya, that's when I'm on plane.