Golden ratio - Irrational Mathematical Constant

Discussion in 'Boat Design' started by Frog4, Oct 23, 2011.

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Frog4Proletariat

The Golden Ratio - How many designers use this in their designs?

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daiquiriEngineering and Design

No golden ratios in naval architecture. Physics, not alchemy, is what governs a ship design.

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keroseneSenior Member

it is not _bad_ tool for certain styling proportion choices but really - in most cases trained eye does a better job. It is one of those things that when analyzing has been afterward forced to fit many successful designs/artwork.

Similar to the kind where you add Hitlers birth date and death date multiply by this and divide by that and you get 666!!!! or something. or those silly facial proportion pentagram things you might have seen in documentaries about beauty.

Certainly the same ratio and Fibonacci sequence 1,2,3,5,8,13,21...(consecutive numbers have same ratio as golden section) do show up a lot in nature. Interesting but wouldn't let it make very big decisions.

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Navy

Dear All,

We observed, that on Navy Ships the General Dimensions (Monohull-SemiDisp/Displ - round bilge)
appears a strong relation between LOA and Beam that based in a function (regression 0.97)
where the constant ϕ is involved:

LOA= (B^F) /ϕ where F=ϕ^ϕ and for ϕ=1,61803398874989
then F= 2.17845756793758
.

We have to note that as Frog4 put the subject on the table.

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Diagram

Regarding the matter please see the attached.

Attached Files:

• Navy Ships GD.pdf
File size:
552.7 KB
Views:
468
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Frog4Proletariat

was also thinking about the 80-20 rule (Pareto Principle), 10% Rule and the 3's and 5's rules within design ...

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rwatsonSenior Member

Which Navy - how many ships ?

Did you include Aircraft carriers ?

8. ListerPrevious Member

Lister

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Round bilge:

Patrol Boats - Torpedo Boats (Lurssen Schnellboote) - Frigates - Destroyers - Battle Cruisers

with LOA up to 180m.

The Aircraft carriers is a combined ship + platform that has completely different
purpose of design.
Actually strikes with her Aircrafts and not by her arms and has no ability to hunt.

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rwatsonSenior Member

The Pareto Principle isn't a design rule like the Golden Ratio, its a statistical principle that may apply to aspects of design

eg 20% more HP will give 80% better fuel economy.

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daiquiriEngineering and Design

Total and complete nonsense. Looks like you didn't even bother to check your theories against data of existing ships.

Here is a capture of a spreadsheet with LOA and B data of several ship classes from various navies around the world, together with a graph where these data are shown as points. In the same graph there is a line given by your mystic formula. Now you tell me what relationship can you see between that line and the data from real ships?

Your attachment lacks the connection with the real world - see the above graph.

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rwatsonSenior Member

Well done Daiquiri - I suspected that it was all too neat, hence my questions.
There is no such thing as a simple solution in this complex world.

For a more thorough discussion on the Golden Rule, the thread at

http://www.boatdesign.net/forums/boat-design/placement-spacing-frames-38717-2.html

might apply.

Do you know the user CaptBill, Adler ?

Last edited: Oct 23, 2011
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Frog4Proletariat

I think you should have asked;

"where" the data came from?
"Which" navy?

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rwatsonSenior Member

We did !!

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daiquiriEngineering and Design

The data in my spreadsheet come from existing ships from 4 actual navies and they clearly show that the "rule" and the following claim
"We observed, that on Navy Ships the General Dimensions (Monohull-SemiDisp/Displ - round bilge) appears a strong relation between LOA and Beam that based in a function (etc...)"​
has no basis in the real world, where physics and SORs (and not mystic ratios and formulas) are what determine the shape of a ship.
If it's the form of my reply, and not the substance, that bothered you, then I'm sorry it has bothered you. Sometimes a person feels a need to double-underline his disapproval of unbacked and misleading claims.

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