We really have two bags. One is a true "ditch bag" by ARC--it has an extra EPRIB and a bunch of flares, (flare gun and hand held) the air horn etc in it.
The one I carry with me in the dinghy and anywhere off the boat has:
Submersiable VHF
Submersiable GPS
Combo Strobe/flashlight by ARC
at least a dozen AA batteries
Hand bearing compass (hockey puck type)
cigarette lighter
Gerber multipurpose tool
Swiss army knife (large with most of the "tools")
Small Pair Vise Grips
Two space blankets
Bright Red plastic tarp
6 Small hand held launching flares
Duct tape (small roll)--electrical tape
First aid kit (bandaides, polysporin ointment, betadine swabs, telfa pads,
gause pads, triangular bandage, ace bandage 2", adhesive Bonine tabs)
Small air horn
whistle
signal mirror
small pad and pencil
copy of credit card, drivers license, and passport if in foreign country.
Small fishing grear pack--line, couple of hooks and lures.
Dinghy spark plug
Dinghy shear pin x 2, cotter pin x 2
Spark plug wrench for dinghy spark plug
All of the above in a reinforced scrim clear plastic waterproof bag (fold over the top, with a strap to carry--it is about 6" diameter and 12" long.
Both of these are right by the helm and can be grabbed in a second.
We also carry personal EPRIB's and Personal submerciable VHF radios and strobes clipped to jackets or life vests if we are wearing the inflatables.
Bob Austin