Peter - right from the USCG Aux website - Item 4 - Visual Distress Signals (VDS):
Recreational boats 16 feet and over used on coastal waters or the Great Lakes are required to carry a minimum of either 1) three day and three night pyrotechnic devices, 2) one day non-pyrotechnic device (flag) and one night non-pyrotechnic device (auto SOS light) or 3) a combination of 1) and 2). Recreational boats less than 16 feet on coastal waters or the Great Lakes need only carry night visual distress signals when operating from sunset to sunrise.
It is recommended, but not required, that boats operating on inland waters should have some means of making a suitable day and night distress signal. The number and type of signals is best judged by considering conditions under which the boat will be operating. Alternatives to pyrotechnic devices (flares) include:
Night Day
Strobe light Signal mirror
Flashlight Red or orange flags
Lantern Hand signals
Note that they do not specify handheld or gun launched.
as for bells - Item 8 - Sound Producing Devices / Bell:
To comply with Navigation Rules and for distress signaling purposes all boats must carry a sound producing device (whistle, horn, siren, etc.) capable of a 4-second blast audible for ½ mile. *Boats larger than 39.4 ft. are also required to have a bell (see Navigation Rules.)
*Under a recent change, a vessel 12 meters (39.4 ft) to less than 20 meters (65 ft) is no longer required to carry a bell on board.
The Coast Guard said: "The bottom-line, a bell is no longer required on a vessel less than 20 meters in length. That of course means a bell is not required for those same vessels for successful completion of a VSC."
this is right from thier website on vsc's:
http://www.safetyseal.net/what_is_vsc.asp