There are several incidences in Theodore Roscoe's US Submarines in WWII of IJN DD's pinging for "no reason" other than that was the way they were performing their escort duty. Even read where a couple of the subs followed the pings to the convoy.
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"There are only two types of ships- submarines...... and targets" Unknown
"you wouldn't catch me on a ship that deliberately sinks itself"- comment to me from a surface sailor. 
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