Re: U.S.S. Yorktown
None of the 3Ds in this thread so far really show off angles that expose the saucer's topside. The underside angles are very interesting. Have you considered taking the "nosecone effect" of the 2ndery hull's bow and also applying it to the tips of the nacelles? I think all three of those caps are going to need more color and texture treatments to make them more visually interesting and realistic-looking.
"The way that you wander is the way that you choose. / The day that you tarry is the day that you lose. / Sunshine or thunder, a man will always wonder / Where the fair wind blows ..."
-- Lyrics, Jeremiah Johnson's theme.