The Union of Naval Architects

This group is intended as a collective of gh users who have a marine background.

Despite the name you do not have to be a Naval Architect to join. Whether you are a budding Optimist Sailor or Admiral of the Fleet please feel free to share and discuss any topics relevant to Grasshopper and the Maritime Industry.

Also acceptable "Off Topics" of conversation include "How will l'Hydroptere fair on her Transpacific Record attempt?" Or "Should Juan K have been appointed the VOR one design, or is he to arrogant to toe the line?".

However I would like to point out that the level of decorum should not descend to that of Sailing Anarchy and there will be no Fridays here! 

Hull tuning with Octopus

HI EVERYONE AND HAPPY NEW YEAR!

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I gave a try at the new Octopus multi-objective solver.

5 objectives :

1 : Prismatic coefficient

2 : Position of main area section

3 : Wet surface

4 : Waterplane inertia

5 : "Finesse" f = WLL/(V^1/3)    _ f stands for "frog" also, I think you use WLL^3/V in the English speaking world. I could have used WLL directly because the hull is set at the desired displacement before analysis - no use to test at random displacement indeed!

---First try on a 40' cruiser with jittery control points and bad volume repartition, a 30-seconds-work to a tee.

Red dots are original points, white mesh is current surface control polygon.

INPUT

After just a few steps I was able to find good candidates. Check the video.

OUTPUT

---Second try on an Open 60' hull. This was an rhino modeling exercise for students, so it's clean and realistic already, and I gave the same objective values as the original to see if it would fall on its feet. In this case I blocked the edges points.

I was amazed to see that It works!

INPUTOUTPUT

See the nice diagram! All points closest to the wet surface axis have good CP and position. On the left, very round hulls with poor stability (purple) and short WLL (big), on the right, wide hulls with higher water resistance (cyan) and longer WLL (small).

This is only one generation. with a few steps more it zooms in where the two sides meet. The two surfaces actually cross and I found very quickly an individual dominant on both wet surface and stability fronts.

I LIKE IT :)))

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    Robert Vier

    I like it too, very nice application!