Tasmania's Spirit of Tasmania IV ferries will soon start crossing Bass Strait after years of delays. (Chris Kidd/AAP PHOTOS)Tasmania's Spirit of Tasmania IV ferries will soon start crossing Bass Strait after years of delays. (Chris Kidd/AAP PHOTOS) Credit: AAPAfter years of delays and hundreds of millions of dollars in cost blowouts, new Spirit of Tasmania ferries are firmly on track to begin sailing on their revised start date. Their revised Bass Strait sailing start date of October 31 was essentially locked in, a parliamentary inquiry was told on Friday. There was also strong interest from buyers for the existing two Spirit of Tasmania ferries, he said.