Abstract: A submersible inspection drone used for inspection of liquid cooled electrical transformers can include a number of separate cameras for imaging the internal structure of the transformer. The submersible can be configured to communicate to a base station using a wireless transmitter and receiver. The cameras on the submersible can be fixed in place and can be either static or motion picture cameras. The submersible can include an input/output selector capable of switching between the camera images, either through commanded action of a user or through computer based switching. In one form the input/output selector is a multiplexer. The base station can be configured to display images from the cameras one at a time, or can include a number of separate viewing portals in which real time images are displayed. The base station can include a demultiplexer synchronized to the multiplexer of the submersible.