I fly at Bong every summer & have been in the ponds more times than I like to remember.
I use the the 2B , just wrap it with electrical tape to make it fully waterproof.
Mine have been in the water for hours and still keep beeping no problem!
Most of my rockets that fly at Bong now have foam in the NC with a space for tracker & antenna.
I landed in the pond by the RC plane field. When I got there the only thing visible was the NC bobbing like a cork, just a beeping away. Rest of the rocket was sitting on the bottom!
L-3 Tripoli 9693 Tap
ICBM Orangeburg SC
QCRS Princeton ILL
MDRA Price Maryland
Woosh Bong Wisconsin
"Made" member of Chicago Rocket Mafia
Rocketry...........an exact science.......but not exactly !!!