Marine signal flag: Letter "U" (Uniform) Size:3' X 5' British Admiralty Nautical Chart 3937:

British Admiralty Nautical Chart 3937: Ports in Kepulauan Riau is a standard nautical chart

British Admiralty Nautical Chart 3942: Ko Lanta Yai to Ko Tarutao is a standard nautical chart

such as the English Channel

1    Example Hose Lifting Method

Porto de Natal and Approaches is a standard nautical chart

Marine signal flag: Letter "U" (Uniform) Size:3' X 5' British Admiralty Nautical Chart 3937:International maritime signal message: "You are standing into danger" Marine signal flags are international signals used by ships at sea to spell out short messages, or more commonly, used individually or in combination they have special meanings.