Ships of the line beating frigates was not a surprise

Was it really surprising that ships of the line defeated frigates, regardless of shell ammunition?

No. Navarino had already shown the disparity; shells made Sinop more destructive without making the matchup unprecedented.

The matchup itself was familiar. At the Battle of Navarino, an allied force including ten ships of the line and ten frigates had already devastated an Ottoman-Egyptian fleet. Large Ottoman frigates could carry impressive batteries, but they were not designed to stand against line-of-battle ships. At Sinop, explosive shells altered the character of destruction, while the basic result of heavier ships overpowering anchored frigates followed an established pattern.