What grammatical error does the phrase "Working far into the night in an effort to salvage her little boat" contain?

The phrase "Working far into the night in an effort to salvage her little boat" is considered a fragment because it does not express a complete thought. A sentence needs to include a subject and a verb to stand as a complete idea, and in this case, while there is a participial phrase commencing with "Working," it lacks a main clause that would provide it with a subject and a verb.

For example, if it were restructured to include a subject, such as "She was working far into the night in an effort to salvage her little boat," it would become a complete sentence. Understanding the concept of sentence fragments is crucial for writing clearly and coherently, as fragments can lead to confusion in both spoken and written language.