Dinghy

The Fifth Doctor kept an inflatable dinghy in his TARDIS. (AUDIO: Eldrad Must Die!)

Earlier on, the Fourth Doctor told Romana II and Adric that he kept a flare pistol in the TARDIS "in case [he] should get into trouble in [his] dinghy", which he kept in case he should get into trouble with the TARDIS. (AUDIO: The Planet of Witches)