Illustrated (yes) guide to the fog signals you should make at ahcnor, aground, underway but stopped, and underway and moving.
Subtitled "More than you ever wanted to know," this article covers 26 two- and three-flag codes that you might someday use, and one that you will definitely use if you enter a foreign port.
There are a dozen or more recognized distress signals you can use if you can't get help by radio. Here's a run-down on pyrotechnic devices.
Nautical bells in brass, cast bronze, and chrome.
Orange plastic ball-type whistle and enameled aluminum fog horn with nylon mouthpiece.