Complex sentence: The Admiralty Board also considered that "Brilliant" too lightly armed for her size; measuring an additional 50 tons burthen over a standard 32-gun frigate while carrying only four more cannon.
Split into simpler sentences: The Admiralty Board also considered "Brilliant" too lightly armed for her size. She measured an additional 50 tons burthen over a standard 32-gun frigate but carried only four more cannon.