Mapping Second World War ships onto the sailing-navy rating system

What ships in the major Second World War navies were closest to fourth rates?

Light cruisers are the closest general equivalent, but the sailing-era rating analogy is necessarily approximate.

The sailing navy's rating system works here as a functional analogy rather than a literal technical match. Heavy cruisers sit closest to third rates, while different levels of capital ship fill the first- and second-rate positions depending on circumstance. That leaves light cruisers as the nearest Second World War equivalent to fourth rates across the major navies. The analogy helps explain relative fleet position, though ships from such different eras cannot line up exactly.