Same X and Y scale

[Sailboats]

Hi! My question is about “Same X and Y scale” command, available on the last versions of Delftship free. Is this command a SWITCH (On/Off)? If so, how do you know when it is On or Off?
Thanks

[Schuchardt]

Hi queqen,

it is a switch. When it is on (Same x and y scale), the Set-scale-command uses only the first value (for the horizontal axis), the second value is ignored and derived from the first value.

For a test, just modify only the second value in the Set-scale-command. If there is no change of the background image, the toggle is on. Otherwise it is off.

Regards
Klaus

[Sailboats]

Thanks Klaus, finaly I learned how to use it. Perhaps Martijn could add a cross box to this switch and make it easier to understand and use.
Regards

[Petter Blix]

I can’t get this to work. It won’t toggle. Its in constant “same X & Y” toggle OFF.

[Francesco]

good morning
After much research I managed to find
I read your article on the 747.
I am not a naval architect.
I’m trying very hard to design a hull class IOM – 1 m with the theories expressed by David Raison.
I saw his drawings and cards produced by delftship.
Much data seem forced, but I’m not a naval architect.
I’d love to work on designs developed by her.
frcalc@gmail.com

[Sailboats]

Calcagni, I don’t understand how can I help you…
I’m not a NA also, by the way, so don’t take my thoughts as accurate info…
What data seems to be forced for you?
When scaling down to 1m you will not find the same behavior because of the different incidence of water viscosity in total resistance, basically to reach the same Froude number you will need:
-more sail area
-more weight on ballast to stand the bigger sails
-bigger fin area to compensate the bigger side-force
-all this leads you to a bigger total displacement
Check the Doug Lord’s scow models, he has a lot of experience in scaled down RC models.

[Francesco]

I apologize for the inconvenience.
I read a review of its boatdesign.net of 15.07.2012 on the 747 by David Raison with some attached images produced from SW Delftship and some attachments with hydrostatic calculations.
I thought that they had produced her.

What I found interesting is that the idea of ​​raison has designed a multi-hull tankers to be rigged.
actually have two hulls joined by a central third.
As the images attached to her.

I simulated with Navaldesigner the hull of Raison and the wet surface decreases with between 25 ° and 35 ° while maintaining good coefficients, and above the waterline substantially longer than with a sailing center that advances and retracts when sailing upwind downwind.

I would like to play the same concept of an IOM hull – FIS 1m.
not a copy.

Sorry for my horrible English

THE IOM class rules of the class are:

C.4 BOAT
C.4.1 DIMENSIONS
With the boat floating in fresh water:
minimum maximum Draught ………………………………………………………………….. 370 mm ….. 420 mm

The depth of hull from waterline …………………………………………… …….. 60 mm

Hull length …………………………………………………………………………. …. 1000 mm

C.4.2 WEIGHT

minimum maximum
The weight of boat in dry condition excluding wind
indicator if used …………………………………………………………. 4000 g
C.4.3 CORRECTOR WEIGHT(S)
Corrector weight(s) to achieve compliance with C.4.2, if used, shall be fixed in/on the hull and not be altered or moved during an event.

C.6.4 WEIGHTS
Keel, excluding fasteners to hull …………………………………. 2200 g ……. 2500 g

minimum maximum Rudder, including stock …..

Attachments:

• Schermata07-2456135alle16.51.57.png

[Sailboats]

Calcagni, the files that you saw at boatdesign.net were made by myself using Delftship (based on Francois Chevalier drawings), they are not original files from Raison. As so, they are just speculations, anyway they show the essence of the concept as mentioned and detailed on that post.
What Raison has done is just a scow, an old and very fast concept used for a long time in sheltered and flat waters all around the world. Raison’s originality resides in using it in open waters, where a scow is supposed to be slow because of his poor capabiliy to cross big waves without bouncing, and his big resistance to manage chop.
I don’t see this hull as a tank trimaran, but just as a tall scow.
I don’t see any problem on scaling down the 747. If you forget the idea of doing a “true” model with his true LOA/DISP, rig, sails, keel and rudders, and if you take care of the IOM rules, certainly you will achieve the same advantages and disadvantages as the 1:1 boat. It will plane easily and fast, but will perform a bit poorly against the wind.
Good luck!

[Author]

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