I might be crazy for trying this but I thought it would be cool to practice some 3D modeling with the Chinese Ning Hai. Oddly enough, the issue I have ran into is marking the water line. The math (with the density of water) says that the max displacement for the current scale is 1.35lbs. However, the ship list states 2.7lbs. Any ideas on what I am missing? Or I could scale the ship by 130% which I can't do either.
I guess I have cut away too much? Bodies (1) Area 317.666 in^2 Density 0.578 ouncemass / in^3 Mass 21.536 ouncemass Volume 37.257 in^3 Physical Material Water Appearance Water - Clear Bounding Box Length 3.271 in Width 29.977 in Height 2.54 in Center of Mass 0.00 in, 14.175 in, -1.513 in Moment of Inertia at Center of Mass (ouncemass in^2) Ixx = 1251.794 Ixy = -0.111 Ixz = -0.003 Iyx = -0.111 Iyy = 30.112 Iyz = 24.231 Izx = -0.003 Izy = 24.231 Izz = 1261.834 Moment of Inertia at Origin (ouncemass in^2) Ixx = 5628.559 Ixy = -0.22 Ixz = 0.008 Iyx = -0.22 Iyy = 79.419 Iyz = 486.151 Izx = 0.008 Izy = 486.151 Izz = 5589.293
Alright, I think I got myself straitened out but my original question still stands. I can't make the Ning Hai to a weight of 2.7lbs as listed in the ship list.
Class 2 and below get an extra pound which is how ships that size end up with a large % difference in max weight vs scale. To add an extra pound, you’ll need to increase the depth of the hull. You can calculate the added depth by taking the plane area at the scale waterline, then convert the added weight to a volume of water, and divide the volume by the plane area. Based on my experience with a vessel about the same size, you’ll need about 0.6” of extra freeboard. I usually stretch the hull sections in the middle so you don’t have a non-scale bottom shape and the deck is also a scale shape
It looks like you have already cut out the middle of the hull shape? If so, then afaik, the system is providing you the water displacement of the hull walls and is not including the inner section you have already cut out. Put differently, try rolling back the time line to a point where the hull was completely a solid chunk & try again.
So, couple things. You should really move a rib to the step. That's a weak point as it sits. Angle the shaft down till you can fit at least a 1" in prop. I doubt you will be able to get to speed with anything smaller. Looks good though!
What kind of down angle are we talking about here? This is 5 degrees. That puts a 1" prop, 1" away from the hull. Does that seem right?
Admittedly, I’m a big gunner… but… It’s a 3lbs cruiser….. does it really need 1” prop to make speed? I would think 1/2” that would get that feather to 22speed.
im unclear at which step in the modeling I do this. Should I model the hull, mark the water line, scale the lower half?
