Vernon Sewell is a B-movie film writer / director of the 1950's who seemed to have an obsession with making films in Shoreham, that included the harbour, boats and often his own boat (which was berthed at Shoreham).
His films to look out for that were filmed in Shoreham are:
Ghost Ship (1952)
https://www.reelstreets.com/films/ghost-ship/and Dangerous Voyage (1953 / 54).
Rogues Yarn (1957),
The Battle for the V1 (1958),
Also see The Flaw (1955)
Here's a curious still from Dangerous Voyage - recognise the spy's secret notes (and featuring a building on the spit with 2 chimneys)? The story was a bunkum about radiation, a bomb and missing stowaways from a salvaged ship in the channel.