One I like is the phrase "the tell-tale signs", which refers to a sailing boat's tell-tales. These are small strings attached to the sails to indicate if the sail needs to be trimmed for optimal performance.
>also tell-tale, "discloser of secrets," 1540s, from tell (v.) + tale. As an adjective from 1590s. Phrase tell a tale "relate a false or exaggerated story" is from late 13c.
Is it maybe that the nautical term comes from plain English?
Quite a lot of folk etymology tries to, incorrectly, assign nautical origins to common words and phrases. I used to read a column by an etymologist that jokingly referred to this using the term CANOE - the Committee to Assign a Nautical Origin to Everything :-)
