A question was recently asked about how Britain would have defended herself against a cross-channel invasion by Hitler. A key element in the British defense would be the Royal Navy. At the beginning of the war, it included (among other ships), something like 15 battleships and battle cruisers, 66 cruisers, and 184 destroyers.
One of the main concerns of the British army was that it had lost most of its artillery, and other heavy equipment at Dunkirk.
The Navy's first priority was to sink the German landing ships and covering naval forces. After fulfilling this assignment, the Navy could have been used as "artillery" to bombard (surviving) German land forces. If the above-mentioned ships were performing this "bombardment" role, how valuable would such support be?
Put another way, how much "artillery," or "firepower," would the Royal Navy represent (in batteries, divisions, or whatever other equivalent units of firepower might exist)? And if were being fired from the sea side, so that German ground forces were caught in a "cross fire" between British land forces and naval firepower, would such firepower be more or less effective than an equivalent amount of artillery supporting British troops from the land side?