Tom..
You're right that many recreational vessels are NOT required to have a VHF but if you DO have one, the way I read it, you are required to maintain watch.This is the last line of that paragraph. "Voluntary vessels equipped with VHF–DSC equipment MUST maintain a watch on either 156.525 MHz (Channel 70) OR VHF Channel 16 aurally whenever the vessel is underway and the radio is not being used to communicate."The " or VHF Channel 16 aurally whenever the vessel is underway and the radio is not being used to communicate." is the clincher here. You still MUST monitor if your vessel has a working VHF on board and the law is very clear on this. If you have DSC it's 70 or 16 if you don't have DSC it's preferably 16 but 9 is an alternative you can use to monitor.. Still how do you use DSC on most hand held VHF's? As of yet there are very few available DSC capable hand held VHF's and the question pertained to use of a hand held device? If you do have DSC on a fixed mount radio get one that meets the Class D international spec of IEC 62238. Radios that do not meet this spec only have one receiver and using the scan feature could result in missing a DSC call! I'm guessing that the term "maintain watch" means just that "maintain watch" and not set your radio to "scan mode". If in scan mode and Joe the tuna fisher starts bragging about the big one, on one of your scanned channels, you could miss an important DSC broadcast... Still what I initially said was directly pertaining to a hand held device and if you own one the law is clear in that MUST monitor either ch9 or 16 which to my original point requires a way to charge or LOTS of batteries. Of course you are NOT required to own one......but if you do!!