SOLAS requires a radio watch on 16, if you have the radio...
From Transport Canada:
From US CG web site on Radio watch keeping:
ITU:
I believe that under international treaty that all vessels which are quipped with VHF Radio should monitor it...is someone going to arrest you? No, but how would you feel if you were near a vessel in distress and did not help when you could have?
From Transport Canada:
Radio Watch
Vessels that must carry VHF equipment must begin radio watch on 156.8 MHz (channel 16) at least 15 minutes before getting under way, and continue until at anchor or moored. If you choose to carry MF (medium frequency) and VHF equipment, you should try to keep watch on both 2182 kHz (MF) and 156.8 MHz (VHF) (channel 16) when at sea, to ensure that distress, urgency or safety communications will be heard and answered by as many stations as possible.
From US CG web site on Radio watch keeping:
Radio Watchkeeping Regulations
In general, any vessel equipped with a VHF marine radiotelephone (whether voluntarily or required to) must maintain a watch on channel 16 (156.800 MHz) whenever the radiotelephone is not being used to communicate.......
Sequential monitoring techniques (scanners) alone cannot be used to meet this ...
Source: FCC 47 CFR §§ 80.148, 80.310, NTIA Manual 8.2.29.6.c(2)(e), ITU RR 31.18, 52.244
ITU:
International Telecommunications Union (ITU). ITU regulates all use of radio spectrum by any person or vessel outside U.S. waters. ITU rules affecting radio, which have treaty status in the U.S. and most other nations, are published in the ITU Radio Regulations. The ITU has established three VHF marine radio channels recognized worldwide for safety purposes:
• Channel 16 (156.800 MHz) - Distress, safety and calling
• Channel 13 (156.650 MHz) - Intership navigation (bridge-to-bridge)
• Channel 70 (156.525 MHz) - Digital Selective Calling
I believe that under international treaty that all vessels which are quipped with VHF Radio should monitor it...is someone going to arrest you? No, but how would you feel if you were near a vessel in distress and did not help when you could have?