In a straightforward gunnery duel between a ship and a fort, within the effective range of each, the former stands no chance. In these days, however, such duels savour little of the old-time broadside fighting between ships. Even the largest and most modern coast guns are of comparatively small avail for defensive purposes unless the attacking ships are visible, or unless the firing can be controlled satisfactorily by such indirect means as the use of aircraft for observational purposes. At night the attackers must be illuminated by star-shell, flares, or searchlights. Under the ordinary fog conditions--i.e., when the whole locality is obscured by fog--aircraft cannot observe the results of firing nor can the attacking forces be illuminated. Under exceptional fog conditions--i.e., when a fog (natural or artificial) lies between the shore guns and the attacking vessels, the latter being in clear weather--good co-operation between the batteries and aircraft in daylight enables the fire to be directed so accurately as to ensure destruction to vessels which remain in the danger zone. [Illustration: A portion of Chart 1406, showing the Dover Strait, the waters between Dover and Zeebrugge, the shoals, the extent of the German minefields, the section of fortified coast (shaded), and the danger zone of the German batteries.] {37} The only alternative to directed firing is that of barrage firing, such as is used so greatly in modern land warfare. The defence guns can establish a shell barrage, for a limited period, across any zone which the attacking ship is attempting to penetrate _en route_ to her objective. The vessel which steams into an efficient heavy gun barrage from modern guns is unlikely to survive. [Sidenote: German Coast Defences] I afterwards visited one of the large German batteries near Ostende, called the Jakobynessen battery, which mounted fifteen-inch guns and fired projectiles weighing nearly one ton each--seventeen hundredweight to be precise. They were mounted in specially constructed gun-pits amongst the sand-hills close behind the shore, and were so well hidden that they could not be seen from a distance of little more than a single gun's length. The projectiles stood over six feet high and were murderous-looking instruments of warfare. These particular guns, and there were others of a like nature, could probably have ranged up to sixty thousand yards (over thirty-four land miles).