# Amidships Chain Storage

Discussion in 'Sailboats' started by Ted Royer, Jul 20, 2018.

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1. Joined: Aug 2002
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### gonzoSenior Member

You can't have fundamental or harmonic frequencies unless this is an oscillatory system, which you state it is not.

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GGGeeesss...this is like pulling teeth.

The response from Mike was thus:

Pleaseeeee...... if you're going to wade in, show some comprehension of the subject and the topic at hand.

Your statement above shows you cannot do either. One is the boat one is the wave, understand???...it is child's play to follow ..!!!!!

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### TANSLSenior Member

Amazing. Could you prove in some way these curious theories ?.
The ship does not rotates around its center of gravity. The dynamics of the floating bodies, not totally submerged, does not say that the rotation occurs around the CoG. I do not think basic mechanics says otherwise.
In a rotary motion in space the movement can not be perpendicular to the axis of rotation.
And finally, what does the seakeeping have to do with the way in which a floating object revolves around its axis of rotation?
Thank you, in advance, for the master class you are going to give me. I ask only one thing, try, please, do not attribute to me animal attitudes or behaviors to explain why I am wrong. I am sure that a naval architect with so much experience, and with education, knows more kind and educated ways to demonstrate my mistakes.

Last edited: Aug 7, 2018
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### gonzoSenior Member

You quote Mike as saying "If that new frequency is close to a fundamental or harmonic of the wave spectra ". Can you explain what the "new frequency"is, if it is not of a system vibrating (ie the boat and anchoring system)? He claims that adding weight to the bow will change it. In a vibratory system there can be three components: mass, spring, damper. Only two are necessary: mass and spring.

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Geesss.....

Just hopeless. Try doing a course on naval architecture before posting!!!!...or better still, read a book!

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Good god. You really have no idea about seakeeping do you....yet you keep posting such erroneous information.

So, since you think you the subject.....please explain what is a natural frequency!

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### TANSLSenior Member

Dear professor (LOL), with a drawing of the last century you will not show that I am wrong and more seeing that this drawing refers to movements around the ship's CoG. I refer to the movements of an object floating, not submerged, in freedom in the water. I have explained it in previous interventions but, as I was saying, I believe that your prejudices are clouding your intellect.
The movements that you explain are not those of an object floating freely, I'm surprised you do not know it, a technician of the category that you think you have. Unless you are saying falsehoods, knowingly, with the sole purpose of discrediting myself in front of those who do not know about this topic.

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Oh dear, so you don't realise that image above is a ship. Now I understand your ignorance on the subject...pictures are difficult to 'read'.

So, let's look at it in words then since you don't understand pictures of floating objects:

and

I could go on..but hey.. seriously why bother.??? You don't understand words or pictures nor known and accepted theories on seakeeping....why..no idea.
Utter nonsense....just nonsense... what a waste of bandwidth.

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### TANSLSenior Member

The composition of movements seems to be a discipline that you do not master at all. All movement can be decomposed into translations of a certain point and rotations around axes that pass through it. Turning in space around a point is an incorrect way of expressing oneself. I think you are trying to discover America, to show my ignorance, and I am sorry to tell you that it is already discovered. You do not need to thank me for the lesson, for you it's free.

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### gonzoSenior Member

I would appreciate for you to moderate your tantrums.
I told Mike that if he is talking about frequency, then the system has to be vibratory. It doesn't matter what the system is or does; if it has a frequency it is vibrating.

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### TANSLSenior Member

Maybe it is oscillating with a certain frequency, which is not the same as vibrating with a certain frequency. My God, science gets more and more complicated. I do not know if I will be able to master it all.

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### gonzoSenior Member

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### TANSLSenior Member

Gonzo, I think you're talking about vibrational movements so delete post #57 and look deeper into Wikipedia.

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Ok...so your university degree course final exam has a question is asks:

Now, i wonder how many marks you would get for that one liner....??
But let's be honest, you do like your one liners - in the vain attempt that it explains all and satisfies those that do not know any better and go away all rosey and glowy someone replied to them.
Mind you, I was expecting the unified theory of everything quote, as that seem to be one of the favorites lately

So, if one is unable to describe what is natural frequency, it clearly suggests a lack of knowledge and understanding of vibration.

And even your google translating friend trying to chime in again, ...but of course google translate can't translate pictures.

The level of technical argument, reasoning and discourse on this thread is shocking. It is an embarrassment to any qualified engineer to read such utter nonsense and should be to any university educational system.

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### MikeJohnsSenior Member

You keep trying to define it as a vibration which I've told you is wrong. I used the term oscillatory. That's the closest it gets to vibration.

You need to you understand what a Response Amplitude Operator is. How the characteristic equations are derived and what they are functions of. And you need to understand what terms like Jonswap mean as excitation inputs before you can comment sensibly.

You will have oscillatory effects driving the peaks of the RAO but you can't sensibly model any complex dynamic system as a spring mass damper.

That's how we ended up here Vibratory System https://www.boatdesign.net/threads/vibratory-system.60751/

Last edited: Aug 7, 2018
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