Early helicopters and naval air roles

What changes if workable helicopters arrive in the early 1930s?

Early helicopters would reshape anti-submarine warfare, ease some escort-carrier conversions, and replace seaplanes for battleship spotting.

Early helicopters are treated as a plausible acceleration because workable concepts already existed. They would make submarines harder to operate against and simplify some escort-carrier roles. They would also displace shipboard seaplanes. Battleships could lose catapults and recovery gear while retaining organic airborne spotting for longer.