Ronald is right. As a naval architect I know a lot about this subject. The centre of gravity can almost be anywhere you want it to be.
Like Ronald said, you want to make sure that your CoG ends up exactly below the CoB (Centre of Buoyancy).
It`s always a good thing to make some calculations of the CoB and CoG before you place everything in, so that you`re sure it is pretty close when you start trimming.
If you need any advice how to do this, please send me an E-mail, and I`ll explain it to you.
Greetings from the Deep,
Edited By Captain Bergevoet on 1050040403