Bosun's Pipe.

I bought this old bosun's pipe made of brass from a maritime antique shop (I've forgotten where). I hooked a length of chain on it so it'll look useful! The modern pipes that are used in the navy are silver ones. The 'pipe' can be tuned by tapering the end of the 'gun' - the part where air flows out over the spherical bowl, or 'buoy'. This can be adjusted to be wider or narrower. The pipe is also commonly called Bosun's Whistle. When used, it emits a highly audible tone which can be heard over any crew's activities and bad weather.