drawing needs scale

I think you can get a rough idea of design sizes. However, if the OP wants accuracy, the best thing is to contact the manufacturer of a dealer. They are usually helpful if it means they may make a sale.

 

Hi everybody,
If on the photo there are some sizes then can Tansl be right, but if there are no sizes then would be very silly to take measurements from a photo and to evaluate scale coefficients on a length, breadth and height if there are clever programs.
I remember that when I was the student did in hand-operated just so, but the computer engineering explicates and there are newer and improved programs. The concurrence is ruthless to those which not can to understand in new programs.

 

Rabah, as always, I can not but admire the accuracy of your statements (although I do not understand them, as often happens to me). I think, humbly, that if there is no dimension in the pictures, it is impossible to scale the plane. I entirely agree with you.

 

Dear Mr. Tansl,
I did not write that when in the image there are no sizes it is impossible to make scaling. On the contrary, it is quite possible. Here is how it is done:
The explanations in the Tutorial are too long, but it is made for precision. Approximately if you want to restore completely contours of a historical vessel. In our case when the question is for sailing yacht, likely our friend has two images of the prototype - the Profile view and the Plane view without deck and he wants to pattern precisely arrangement of sails and arrangement of accommodations under deck.
1. The first step - it is necessary to make model. There are two alternatives: you do it on the familiar program and then with IGES file you export model in program Free Ship +/ I already has said that she is free /. The second alternative - straight in Free Ship + you create new model with yours L, B and draft. Thus there is no meaning that contours differ from desirable.
2. The second step -With the Right button of the mouse it is necessary to click in Profile view of the model and to call Background Image, then Load Image file.
3. The third step - Again with the right button of the mouse it is necessary to click in Profile view of the model and to call Background Image, then select Origin. We move the image so that the point of the lower edge of the transom from the image has coincided about this point on the model.
4. The fourth step - we put the cursor on the cross point of the stem with the deck at the model and we note coordinates X and Y.
5. The fifth step- Again Background Image, then Set Scale. Must select in the image too most cross point of the stem with the deck and it is noted in the table the coordinate X and Y, received from model in the Fourth step.
Dimensions of the image are superimposed with dimensions of model with an absolute accuracy.
Too most it is necessary to make and for the Plane view. It is desirable to have images of the prototype with possible most proximal ship dimensions from our model for the demand of the necessary sanitary minimum for dimensions of accommodations.
Cunning of this method is in the possibility with the cursor of the mouse you can receive coordinates of absolutely all desirable points from the image.
And if all this has made in program Delftship Professional then there is and more one possibility - To use coordinates of points of the image from Profile view for making the Silhouette. The program automatically evaluates the windage area for the specified draft and centre of gravity of this area.

 

Rabah, too much text and too deep to read.
Thanks for your efforts.

 

For sure, I totally agree it would be out of his skillset - which is why I volunteered to try it for him. Photocopying and manual methods like scale rules would be just too fraught, as you said.

We may never know, the original OP has probably been scared off by the influx of data - it probably seemed so simple originally.


Rabal
"Dear Mr. Tansl, I did not write that when in the image there are no sizes it is impossible to make scaling. On the contrary, it is quite possible."

On behalf of Tansl, may I say that your excellent step by step instructions omit one VITAL step - how will you know the ORIGINAL DIMENSIONS, not "coefficients "
"if there is no dimension in the pictures, it is impossible to scale the plane"

Scaling is never a problem, and the ratios or co-efficients of the plan or elevation of the hull are easy as you point out, but unless you know the original dimensions, you have no starting point to scale to.
1/5 of Unknown = Unknown
Unless you can find some feature or fitting of a know size ( Porthole, Door, Antennae), you are starting with Unknown.


The only thing that can be done, is to prepare drawings and then take them to the required *final* size. They can be stretched or shrunk to a required final size, irrespective of the starting dimensions. of course, that may mean a totally unworkable design like a door too narrow, porthole too large.

 

This is a good start, as you've reduced the unknown by 80% . . .

 

Dear rwatson,
I disagree with you. At each advertising brochure for sailing yachts there is a text part except for images. And in her always there are published data on principal dimensions. So that which is selected the prototype he does not do it in blind and can be guided very well.
Certainly after scaling it is not necessary to accept absolutely all sizes as the fixed. It is necessary to observe rules of Classification organization about passes and coamings of the doors. It is necessary to have in mind standard sizes of outfitting producers like doors, windows and so on.
It is not necessary to pattern all from the prototype. He should serve only as a landmark. It is necessary to have the design approved by classification bodies before to make the yacht.
-------------------------------------------------------
Clever people speak that the Devil too can read the Gospel!

 

As you very well know, because you have more than enough experience to know it, the dimensions shown in an advertising brochure can almost never determine exactly what they mean or where they are measured. Therefore, in my opinion, if the OP needs a drawing with exact dimensions to make some calculations, it will be very unwise if he follows your instructions.
Think about, do not do as you did when you were a student (before yesterday) and try to be strict in what you say to others to do. Note that, at last, after all, you're only naval architect, nothing else. Therefore, you should review carefully.
You should also know that you can build yachts without being approved, their designs, by classification bodies.

 

Images in a brochure can also be distorted, stretched in just one direction or other wise made to fit the allotted space available, sometimes for security reasons, though more often to "stretch out" her look and make her aesthetically more palatable. Think of this as the airbrush job they do on models in advertisements.

 

Once there was a draughtsman who drew the hull lines on paper. Someone copied it on sheet rubber, streched it sideways, stretched only the middle, stretched the width. A NAVAL ARCHITECT was born!

 

Then he got access to the internet, and boats started sinking.

 

You guys need to grow up.

PAR only stated a simple fact.

And Naval Architects are people too.
Doesn't mean everyone of them are good, or that anyone throwing stones make any sense.

 

upchurmer. There, I have added a lot of smilies in my post. Satisfied?

 

Dear Tansl,
It is not my instruction. It is Manual of Delftship Pro and FreeShip +. Principal Delftship Pro it is Mr. Van Engeland - Holland, and the author of program FreeShip + is Master of Tech.Sci., the senior lecturer in Institute in city Nikolaev - Ukraine, engineer Victor Timoshenko.
Before to enclose on destructive criticism created by them software, think how much you far of the position of these respected people.
About the sizes L and B you is right, but it is important only for a choice of the prototype. You can is simply accept what is it out-to-outs of the hull. After the choice of the prototype you already work with his image instead of with digits. See once again that I have written - first of all it is necessary to make our model, with our L, B and T!
_______________________________________
Always it is necessary to remember as the Devil read the Gospel!