Motoring a catamaran on a single engine

If you sail a cat, you probably already know that most of the time you only need to run one engine. This is because cats are quite efficient motor boats with just one prop running. If you're motoring or motor sailing on two engines, you're wasting a lot of fuel.

Here's why:
blog.arribasail.com/2015/01/tech-on-yaw-torque-prop-helm-and-froude.html

Only with both mains running!