What was an Age of Sail razee?

What was a razee, and how did it differ from a purpose-built heavy frigate?

A razee was a ship of the line cut down by removing a deck, retaining the heavier hull structure and weight-carrying strength of its original construction.

Removing an upper deck turned a ship of the line into a frigate-like vessel while preserving exceptionally thick timbers and structural rigidity. That strength allowed a razee to carry heavy guns and absorb punishment beyond the expectations attached to an ordinary frigate. American heavy frigates pursued some of the same combat effect, but they had been designed from the outset to sail as frigates and could not simply copy ship-of-the-line construction weight. The two categories can be compared without treating them as the same design solution.