Three Japanese minesweepers have been named No.7 minesweeper (第七号掃海艇, Dai Nana Gō Sōkaitei, "W-7"):
References
Japanese minesweeper No. 7 Wikipedia(Text) CC BY-SA
Three Japanese minesweepers have been named No.7 minesweeper (第七号掃海艇, Dai Nana Gō Sōkaitei, "W-7"):