Water sports in the evening sun

As I was taking the dog for a walk down by the river the sun was just going down but shining brightly on all those still active on the river at 6.30pm. Within a few minutes I saw - at least 5 rowers, over 20 canoeists , 7 paddle boarders, 2 of the Go motorboats that you can hire by Kingston Bridge and 2 chaps on motor powered small surf boards which were raised above the water …not sure what they are called, they were travelling quite fast over 20mph I should think. ( too fast for me to take a photo) I’ve just tried to find something like them and there are products called eFoil surfboards…very expensive….over £2000