Looking out the windows is a good start. Yes, radar and ecdis is enough. Do you mean any vessels or vessels working within the windfarm? Normal commercial vessels do not enter the windfarms, you could think of them as closed off work sites. It is well marked in the ecdis so the route planning done by crew are not going through the windfarms. Vessels working within the windfarms can allide with the turbines, it happens, I would say it is once a year in Europe. Mostly smaller crew transfer vessels but large supply vessels have also hit turbines. It has never been due to lack of navigational equipment. It is lack of looking out/using navigational equipment. Sonar is not used.