This is slightly off-topic, but the effectiveness of depth charges is partially derived from the displacement of water next to the hull of a submarine. The hull of the sub is designed to withstand the slow, steady pressure of the sea. When a depth charge detonates close enough to the hull, the force of the explosion displaces a large volume of water, and if the resulting (temporary) vacuum comes into contact with the hull, the sudden decrease in pressure can cause the hull to rupture. Needless to say, that's bad news for the submarine crew.
Considering how depth charges capitalize on the added pressure in water to be more destructive to submarines even if it is not an actual hit, I don't think explosive force is an issue.
EDIT: So I guess I'm not following your argument here. How is explosive force not going to be an issue here?
I'm not seeing how being a droid stops the shrapnel from damaging them? They'll need to be out of the potential line of effect drawn from the blast center regardless, or they might get perforated since the fragments won't slow down or be affected by gravity as they would in a planetary environment.
Now concerning shrapenal, that could be an issue, on the other hand they aren't exactly organics either, so it's not like they will experience explosive decompression (which is why I specified the attackers be droids).