If there are none available then the missile can either hit or miss. The other ship will deploy one anti-missile volley that can only intercept one missile at a time. It will fly over the top of the ocean and it will move towards the target.
These can be used in ship to ship combat… but will not fit into a proper defense. There are a few ships that have mortars, howitzers, and rocket artillery. When choosing ships for naval combat remember that you will need to have one or both of these on each ship to be effective in ship to ship combat. Not all ships will have both of these… or either of these. To counter these you have Anti-missile defense which can be seen in the tag… and most often these are area of effect weapons or
Most of these are ASMs or Anti-Ship Missiles. Any weapon that reads on it is used to destroy ships.