Fifty extra Sunderlands against U-boats in 1940

How much difference would 50 additional Short Sunderlands make to Coastal Command in 1940?

They could cover important passages and force the small operational U-boat force to spend more transit time submerged.

The scenario adds 50 Sunderlands against roughly 20 operational German submarines at a time. More aircraft could cover water and watch passages into the North Atlantic. For the earlier submarines, extra time submerged during transit would reduce effective operating range. Their character as submersible torpedo boats makes pressure on surface movement especially relevant.