Yes, that is true. When you use two engines on a boat, if they spun the propellers in the same direction, the boat would also go a bit sideways.
By having reverse spinning engines/propellers, the side forces cancel each other out and go straight, instead of adding up and going a bit to the side....
I knew a guy that used to work for a local public works department who told us about the reverse spinning marine engines. They had some where he worked. One day one of the "reverse spin" engines disappeared. He was waiting to hear about someone who tried to put it in a car and it didn't work....
