Very nice ship! Great work so far.
I recommend the following thread http://boringmordheimforum.forumieren.com/scenery-and-terrain-f4/mordheim-scale-ships-for-sartosa-t1459.htm?sid=ba73d65de6f76705783eca444fcbfdb6
There are a bunch of links to research and other ship builders work.
I would recommend adding a lighter color of wood work either as the deck or a band of lighter boards on the hull.
Actual ships also had painted hulls and railings as well. Your ship could benefit from something as simple as a quick dry brush with a lighter brown.
Keep in mind that sails and details like lanterns and bells will add color as well.
Here's a photo of my first completed ship the OS Ferlangen
Again great work!
And then I remember that you want help with a ship for Undead Pirates. Your ship has risen from the depths! It needs lots of aging and damage and barnacles and the like.
Here's a toy ship for research
Hope this helps,