The Bibliothèque nationale de France is where the Paris Manuscripts, the manuscripts in which the double hull design appears, currently reside. During the Italian capaign, Napoleon took many of Leonardo's works from Italy and sent them back to France. Although some of Leonardo's works were sent back to Italy after the end of the Napoleonic Wars, for example The Codex Atlanticus, most remained in France.
Source:
“The Strange Vicissitudes of Leonardo's Manuscripts.” UNESCO, 3 July 2018, en.unesco.org/courier/octobre-1974/strange-vicissitudes-leonardo-s-manuscripts.

Da Vinci and the Renaissance is a fully cross-disciplinary study-abroad program that explores the transition from the medieval period to the Renaissance across multiple subjects (art, architecture, engineering, science and more), laying out how much of what we take for granted today about technology or about the human subject were implemented in this rich period, especially in Italy.