Beast Wars: Transformers - Season 3 Episode 3 Changing of the Guard
Overview: Unable to jury-rig defenses using parts from the Ark, the Maximals send Rattrap down under water in a small capsule to retrieve Sentinel from wreckage of the Axalon. But Megatron wants to lay his hands on it too, and Rampage and Depthcharge fighting it out in the area, nobody's safe.