Answer: "Hung about a suspected" means to remain or stay in the general area of a location or place that is suspected or believed to be relevant or significant in some way.
Explanation: In the context of the passage you provided, the phrase "the Wasp hung about a suspected tanker rendezvous point" means that the Wasp remained in the vicinity of a location that was believed to be a possible rendezvous point for a tanker and the Prinz Eugen, a German warship.