Ship: [url=http://4.bp.blogspot.com/_L-deInbQA9c/SzrxcQVaLEI/AAAAAAAAFoo/23qNh1mFRJY/s1600-h/ship16.jpg]This [/url] (but a slimmer version of it)

Flag: [hider] In this case the smiling skull[cause we're pirates of course] nestled between two lotus flowers, but have the petals long and curved, like scythe blades for some extra flare. 

The flower pointing left would have all its petals curved upward, and the one of the right downward, to give the flag kind of a 'spinning blade' look to it with the skull in the middle.

Oh and just add two crossbones to the bottom of skull in an elongated cross pattern since pirates have to have those somewhere.

Like the Lotus Flower image but there are two, one to the bottom left of the skull with crossbones, the other to the top right of the skull and have the petals curve like blades clockwise.  

That or have them symmetrical so they are at the same height and sandwich the skull between them, but with this formation it would be better to have one with the petals clockwise and the other counterclockwise to keep it symmetrical. [/hider] 
For reference: 
[url=http://orig04.deviantart.net/6f82/f/2009/024/7/9/794b573d7a9eabec564fc06a1585b52a.jpg]Lotus Flower[/url]  

[url=http://pre06.deviantart.net/caa7/th/pre/f/2008/105/9/a/whitebeard_flag___white_cross__by_zerocustom1989.png]Whitebeard Flag[/url] (this image is in reference to the elongated cross pattern)

Crew name: Twin Lotus Pirates.