Do unpowered sailboats at sea also need documents?

Unpowered sailboats at sea need documents.

Whether an unpowered ship has a grade certificate depends on whether the shipowner applies for classification, and an unpowered ship can also apply for classification and obtain a grade certificate.

Unpowered sailboats, by implication, are all powered fake sailboats. The so-called fake sailboats do exist, that is, they look like sailboats with sails. In fact, the power is driven by the engine, so they are called fake sailboats, which is called "unpowered sailboats"

Tracing back to the source, any sailboat can be defined as a ship that mainly uses sails and is driven by wind, and can be called a sailboat.