You seem to use a lot of ducted propellers, also known as Kort nozzles, on your ships. Just so you know, they're rarely used on high-speed vessels because beyond very slow speeds, the drag the duct produces outweighs any advantage they provide, so it winds up making the propeller less efficient. Wikipedia has a short and easy to understand article on ducted propellors that explains their advantages and disadvantages. Here's the link for it:
http://en.wikipedia.org/wiki/Ducted_propeller
There are a lot of other issues with your designs, but I'll let others nitpick at them.