Does anybody know any movies or stock footage with 1800's docks?
so I wasn't able to find any footage from the 1800s (probably because video was very new and not too common back then) but I have found some old footage of docks which I think might be of interest.

London's Lost Docks DVD clip (1980s)

                
             
This is about a minute of a Documentary about the London docks and may be of use.

Britain's finest hours: The battle of Trafalgar 

                
            

This is a recreation of a battle between the UK, Spain and France overseas in 1805.

Another video on the battle of Trafalgar and is using a game to try and recreate the visuals: 
                
            

Lastly here is some footage from Liverpool docks in 1950

                
            

I hope this footage can help and if it doesn't I am sorry and I fully agree that finding the footage is hard XD

Have a nice day.