 He also participated in the salvage and exploration of the wrecks after "Kronan", "Riksäpplet", "Resande Man", and "Lybska Svan".Franzén studied naval architecture at the Royal Institute of Technology (KTH), but instead developed a strong interest for history and never graduated.He took employment with BP and later changed to the Swedish Naval Administration (which was a single-service forerunner to the Defence Materiel Administration, FMV) where he became an expert on oil and fuels.