Thank you all for the replies. Interesting idea to use interlocking foam mats that you can slide around! Presume you get them in blue? 
I looked at the Navwar site, and they deal in 1/3000 scale ships and seem reasonably priced, so may go for that scale. It depends a bit on how many ships I need to get for a good battle for 4 players. I haven't bought the rules yet, as doing my research before biting the bullet. How many ships and of what types would I need to have in my supply to be able to run a good number of different scenarios playable by 2-4 players? I am thinking about 3-4 ships a player, but not sure what breakdown of types i might need.
As an example, Navwar sells fleet packs which consist of 6 capital ships, 4 cruisers and 8 destroyers. If I bought one of these packs for each side would that give me enough ships of the right kinds?
Also, what other bits and pieces do I need to get to play the game e.g. blast markers, airplanes and so on?
Basically, just trying to sort out what I would need to purchase to get what I need to see if I want to go for it and order the rules and the other things I need, so advice very much appreciated.