Sunderland combat power versus Catalina availability

Which was more effective for Coastal Command, the Short Sunderland or the PBY Catalina?

The Sunderland was the tougher combat aircraft, but the Catalina could be obtained in greater numbers.

The Short Sunderland was a formidable aircraft to fight, while the PBY Catalina could be acquired in larger numbers. Those strengths answer different parts of the maritime-patrol problem. One concerns the capability of an individual aircraft; the other concerns how much ocean a force can cover with the fleet it can actually field.