4th Workshop on Maritime Computer Vision (MaCVi): Challenge Overview. - Benjamin Kiefer; Jan Lukas Augustin; Jon Muhovic; Mingi Jeong; Arnold Wiliem; Janez Pers; Matej Kristan; Alberto Quattrini Li; Matija Tersek; Josip Saric; Arpita Vats; Dominik Hildebrand; et al. (CoRR, 2026)