This video brings back memories of when I raced my first r/c model boat in the sea in the late 1960's.
It was an Aerokits Swordsman fitted with a Merco 61 Twin Spark 10cc glow engine that I made from the Aerokits kit.
This event was held in the sea off of Torquay and was "round one" of the off-shore series being held that year.
The boat survived for many years after that, but I sold it when I got married and moved to Exmouth in 1971 (cash flow was a bit tight then - and surprisingly there was not much interest in model boats in the East Devon seaside town!).
I often wondered what happened to it - hopefully somebody else had as much fun with it as I did.............