By law if the boat is equipt with a Marine VHF radio, channel 16 must be monitered at all times. see: FCC 47 CFR §§ 80.148, 80.310, NTIA Manual 8.2.29.6.c(2)(e), ITU RR 31.17, 33.18, AP13 §25.2
http://www.navcen.uscg.gov/marcomms/watch.htm
In many parts of the country there are other channels which commercial or charter boats frequent, and there is very good reason to moniter these radio channels also. For example channel 13 is the tug channel. In the Seattle area(including the the VTS is on channel 5A or channel 14 Although a boat under 65 feet is exempt from the VTS, "Passive listening of the appropriate VTS frequency for your area is highly encouraged! ".
I always moniter VTS when I am in the Puget Sound area--"The traffic lane network in the Puget Sound begins at buoy J -"Juliet" north of Cape Flattery and continues all the way to Tacoma's buoy TC -"Tango Charlie" with Rosario Strait, and Haro Strait bound branches stemming from buoy SA -"Sierra Alpha."
The problem with monitering only one radio with a scan--which has a priority on 16, is that you can miss an improtant call during the scan. For example--there is a section called the "Rock pile" on the Atlantic ICW, all vessels are to give securitee on channel 16 (and 13 for commercial). I gave Securitee calls on both channel 16 and 13, and a tug was giveing a call on 13 when I was calling on 16 and visa versa--so we both missed each others call, and met in the middle. Since I was the burdened vessel, Ihad to back a 62 foot motor sailor about 100 yards, until I could put the boat on the bank, and let the tug and barge inch by.
The point is that it is important to moniter the safety channels. I find that it is very important for me to have a second radio dedicated to channel 16--then you can use another radio for 68, 69, commerical traffic etc.
In Scott's case, I suspect that for some reason that the other C Dories had their radios turned down or on some other frequency. I would suggest that at a niminum that a hand held vhf--which every boat should be carrying-- be used for the second radio to either moniter channel 16 full time or to be used to communicate on another frequency. In an area as crowded as the Puget Sound, I suspect that there is not much "chatting" going on with the Marine VHF radio. We try and keep our traffic on ship to ship channels pertintant to boating and brief--ie. "Wetneck, what is your position and are you catching any fish?". " Thataway, we are at 87.57.09, 29.58.56 and the bite is on for red snapper". Wetneck--roger, we will be at your position in 20 minutes Thataway clear and monitering 16 and 68".
