Better suited for use against naval targets were the four heavy naval batteries installed by mid-September: "Friedrich August" with three barrels; "Prinz Heinrich" with two 28 cm guns; "Oldenburg" with two 24 cm weapons and, largest of all, "Siegfried" (later renamed "Batterie Todt") with a pair of guns. Fire control for these weapons was provided by both spotter aircraft and by DeTeGerät radar sets installed at Blanc Nez and Cap d’Alprech. These units were capable of detecting targets out to a range of , including small British patrol craft inshore of the English coast. Two additional radar sites were added by mid-September: a DeTeGerät at Cap de la Hague and a FernDeTeGerät long-range radar at Cap d’Antifer near Le Havre.