The underwater hull is designed to fit the hull of the Navis model of Viribus Unitis. but should fit 1/1250 scale models of any of the first three members of the class (Tegetthoff, Viribus Unitis & Prinz Eugen) with 4 Parons turbines and four shafts. (Szent Istvan had different turbines and a two-shaft installation). These battleships were designed for service in the warm waters of the Mediterranean Sea and had a copper anti-fouling coating.