the coasties did get there before she went down but was along time i did just stay in area to do what i could which was nothing.was surprised not more boats would try to help
Boaters are supposed to monitor channel 16. Often they only monitor the local chat channel. Most don't use or know how to select dual channel scan.
Morally and to an extent legally you are required to render assistance of course without putting yourself in danger. What you did was exactly correct. If you monitor the radio you may hear the authorities ask some questions about number of passengers, adults and children, whether they are wearing or have vests and the nature of the distress. If possible and you can approach without putting you or the other vessel in danger, you can do so just to let the vessel know you are there to help. Have your PFDs handy in case passengers on the vessel in distress decide to abandons ship. I have seen that happen purely due to panic.
On the other extreme, if the distress situation was not life threatening and you could approach nearer without risk to either vessel, do so slowly and ask from a distance if everyone is OK. Decide from there if you can offer assistance or perhaps just stand by.
Now for my pet peeve comment not directly related to the posted situation. I monitor my local chat channel and 16. When I hear a radio check request, I don't often know what channel it was sent on. Yes, you are not supposed to ask for a radio check on 16 but people do that often. When I request a radio check, I state the channel I am transmitting on. For example, May I get a radio check on channel 68?
I will not respond to a request if I am not sure what channel it was sent on.