No, what the "BOLD" did, was it contained certain chem's, inside of it... was perforated so that water could get into the decoy container... & once water hit those chem's... started a chain reaction... that created a crap ton of bubbles... (If you've ever watched "The hunt for Red October", is a couple of times in that movie, that decoys were used, by modern subs.
2 times, that I recall of... once with 1 scene with the Red October & another time with the... "U.S.S. Dallas" aka the famous sub broaching the surface scene.)
Think that some later versions had some... recorded sound that was to make the enemy DD or DE think they had a lock on to the sub... that started not long after the chem reaction started... iirc... has been some time, since I looked at the particulars on them, to be frank about it.
The basis for it, is not in mimicking a DC explosion, but... to actively decoy the hunter from its true prey... the U-boat (or later on, any submarine... for that matter... but, those are way more... sophisticated than the early on decoys used by the Kreigsmarine, were...
)
M. M.