Re:how to connect a sent fin keel to the hull.

[otaku]

You’re welcome.

I noticed that too, that moving the hull up or down makes some difference. In my case, since i’m designing cruiser/destroyer hulls (my hobby), and i have a sonar dome in a semi-bulbous bow, they hydros are automatically impacted. A bad shape really detracts. Depending on your model, if you really move the hull too far down or too far above the baseline in the interface, you may get the Design Hydros, but you will get an error message and no appearance of the plain Hydros (resistance/speed) report. I got that with a Carderock 5415 model someone put on the Internet. For maybe a year i had not a clue as to what was going on, and in frustration i cursed the model maker and set it aside. Only a few weeks ago i serendipitiously noticed and changed the model position and could then make comparisons of that hull compared to mine. The perils of not knowing…. hehehe…

Don’t forget that you can use the Add Flow Lines tool to visualize what happens when you modify the hull shape. You have to press (IIRC…see the manual… if you have pdf, search on just flow or flow line) ctrl+ click on a waterline or submerged featured. The flows will, according to Marven, pretty much pattern CFD, even tho he has not intended nor asserted that this IS CFD. So, if you intentionally detract from your hull to see bad flow lines, they should appear. Optimize (manually or automatically) and the flows should restore or reimprove/improve.