A Singapore-registered passenger ferry and a Marshall Islands-registered tanker collided off Singapore’s Southern Islands, the Maritime and Port Authority of Singapore (MPA) said, adding that all passengers and crew were safe.The ferry, Horizon 9, was en route to HarbourFront Centre when it collided with the tanker La Digue at around 5 pm local time, the MPA said.A patrol craft was deployed to escort and guide the ferry back to port, where all 165 passengers and seven crew disembarked…