Fishing Boats off Brighton, 19th century

It’s the West Pier.

The Palace Pier didn’t open until 1899 so it only just made an appearance in that century.

The Chain Pier survived until 1896 but it had a distinctive set of towers that aren’t visible here.

Further confirmation can be seen on the right of the painting. The entrance of the West Pier is directly opposite Regency Square. Follow the line of the pier across the painting and you can see it meets the land at a point where we can glimpse the recessed square between the buildings.