"English School, 18th century" looks to be by Johann Baptist Bouttats

Jackson's, from the United States, sells on 19 November 2019 an "English School, 18th century" naval scene, estimated at $300 to $500.

The painting is "Indistinguishably signed and dated 1745 lower left", but luckily they provide a decent image of the siganture and date.

It looks to me as if it says "J. B. Bo...tt... 174 (1?)". The most logical name is probably Johann Baptiste Bouttats (1680s-1743), last major painter from the Bouttats family, who migrated to England (Hull) in the 1720s. 

Different marine scenes from his hand are known. While they are comparable in general, they seem to be generally more detailed; considering that this work comes from his very final years, while his better works were ten or more years older, this may be understandable. 

As a signed, attractive work (that needs cleaning)  by a known artist, it should be worth 10 times the estimate probably.