In the early morning hours, a navy frigate was underway in darkness and good visibility at about 17 knots. Its navigation lights were on, but the AIS was in receive mode only and therefore was not transmitting own AIS information – as is sometimes the case with military vessels.
The bridge was manned with an OOW and another six crew including two lookouts and a helmsman. The OOW called the local VTS by mobile phone, informing them that the frigate would enter the VTS area from the north and...
https://www.marineinsight.com/case-studies/real-life-incident-symphony-of-errors-lead-to-collision/