Ship Hull Design - Bulbous Bow and Aft section


#1

Hi,

I am designing a ship hull and having problem in creating the surfaces. I have created a bulbous bow, tip of the bow, and two separate stern sections along with the rest of the ship hull. Now I am not sure how do I connect these surfaces together to form a smooth hull.

Ultimately I will use this hull for hydrodynamic calculations using WAMIT and AQWA software. So I need an IGS and GDF file.

I have attached the file I have created so far. I appreciate any help in creating the final hull form.

Best,
Amitava

surface_v1.3dm (2.1 MB)


(Pascal Golay) #2

Hi Amitava - it is pretty hard to loft a lot of polylines together and get clean surfaces. I would probably split the bulb surfaces up- I cannot tell if the bowline is meant to be a hard crease in this model but I’d guess not- in that case I would make this highly curved surface a separate surface, probably. It looks to me like there is a fair amount of work here, making new clean curves over the polylines- (not so great as surface input usually) , it may be that you do not need to actually work from a curve at every point there is a polyline- that might be over defining the shape- not sure yet. I’ll have a try at it if I have some time, to see if I can suggest a good way to proceed here. Someone else may jump in as well.

-Pascal


#3

In addition to what Pascal says, I think it would be wise to split the hull at the cl and shrink the resulting surfaces, trim the curves too and work on one side only, as the hull does not appear to be truly symmetrical.

Also, you may get a better feel for fairing the hull if you scale the 3d model and its geometry to full size and if you plan to produce fewer new curves then you could lock up the existing polylines and surfaces on colored layers to use as your guide.

If you check out this link to Gerard Petersen’s informative blog, and click the link to the PDF tutorial, you’ll get some very helpful tips on how to keep the input curves to a minimum to end up with clean surfaces and there are also tips on how to form a bulbous bow and manipulate control points.

Edit: link fixed

Rhinocentre