Sure, all valid issues. It for sure would expose the general vicinity. In terms of noise, keep in mind that submarines have all sorts of concessions already. A

Sure, all valid issues. It for sure would expose the general vicinity. In terms of noise, keep in mind that submarines have all sorts of concessions already. A diesel-electric sub is quieter than a nuclear sub, but it has to surface every two days or so to get air to run its very noisy diesel generators. I think a battery powered electric drone should be far quieter than any sub technology we have (steam/nuke is loud, diesel is louder). The quiet systems we have are all electric and therefore have limited energy capacity.