The Race to the Sea was not, in fact, a race north to the coast, but a series of manoeuvres by both the Allied and the German forces attempting to envelop the northern flank of the opposing army. The Germans were hoping to capture the northern ports, and cut off the British supply lines. The British were particularly worried that if the Germans had control of those ports, the German U-boats (submarines) could pose significant threat to the Royal Navy. They too, saw strategic advantage in disrupting the German supply lines.
Neither side was successful, and as the opposing forces tracked north, battles were fought in Picardy, Artois and Flanders. By the end of the year, the ‘Race to the Sea’ had ended in a draw, and two lines of trenches had been dug, stretching more or less from the Belgian coast to the Swiss border.