One of those "blockbuster" bombs went off accidentally in Frankfort, once again in a river.*
I'm thinking maybe they don't necessarily go off when they hit water.
In any case, I guess if possible, we should follow the firecracker rule "lay on ground, light fuse, retire quickly" instead of trying to defuse them. In other words, set them off with an external charge, where they'll either explode on cue or be blown apart into smaller manageable pieces.
Terry, 230RN
*ETA According to the original reports and video of the event that I saw.. Later versions indicate it was a smaller bomb and was set off deliberately. = ? ? ?