The tell-tale compass is a type of magnetic compass that has been around for a long time. Historically, it was used by the ship's captain to keep an eye on his vessel's heading, when he was belowdeck–for instance, when he was bedded down for the night. Thus it was that the tell-tale compass was designed so that it could be mounted overhead–usually above the captain's bunk–and was read from underneath.

Today, the tell-tale compass may still serve that same function on extended trips. More commonly, however, it is used at night to monitor wind and current changes when at anchor.

Many boaters like the idea of using antique tell-tale compasses. These can be quite beautiful, but they are also inclined to be pricey if their condition is good. Alternatively, there are new models on the market. Some of the more recent designs include markings on both sides of the compass card, so that they can be read from above and below.

- Linda Hoff