The maritime example of EPIRB+VDR was just for comparison. In terms of SAR the required device would be best equipped with a radar transponder (SART). As CJ pointed out, having the exact GPS distress location at sea will give you an exact idea of which SAR unit to scramble but not necessarily exactly where to look. Without either continuously updated GPS coordinate transmission or a SART the search is less likely to give a positive result.
In the maritime field such equipment exists but there would need to be extensive engineering research to ensure survivability and operation in such a case as we have here.