well, here we are at an interesting point. to make your design correct and loose all the work you did on it, or keep it incorrect. the latter is easier, the first is more satisfactory. it's an choice we all make countless times.......
anyways, especially on this ship you lack a lot of freeboard
http://img534.imageshack.us/img534/4029/b1dc.png
the other carrier,
http://img441.imageshack.us/img441/3390/bcv3.png, has enough freeboard but lacks hangar height.
note that you should compare with the US carriers when you have 'open' hangars and to the british if you have 'armoured' hangars. every aspect of the designs comes from those simple design starts.
also, obsydian shade, please note that the freeboard is not the height to the flight deck on a carrier, but the height from the waterline to the main deck, which is the first deck which is 'open' and thus is no longer part of the hull over at least part of the ships length. freeboard can thus be calculated by the hull depth (height from keel to main deck at midship) minus draft (at the keel, with 0 trim).
on the Roanoke, this might mean that the main deck is even the deck with the casemate guns on them, but even when it is the deck on top (which I suppose is the maindeck, which it is if the casemate guns are enclosed watertight) you have an very low freeboard for a ship this size, especially an carrier. this ship also seems to be underpowered, if we take in account the speed requirements for carriers and the single funnel (but 4 props!) of this ship.
on the non carrier ships, note the lack of sheer, which might require you to have a bit more freeboard then comparable ships with more sheer. the destroyers look a tad top heavy to me.