A report into the capsize of the Easy Rider fishing boat, in which eight people died, says the vessel was overloaded, the skipper was unqualified and there were not enough life jackets and rafts to save those on board.
The Transport Accident Investigation Commission's findings are critical of the skipper and say drugs and alcohol were used by the crew.
The stability of the Easy Rider was a major factor in its demise. Commissioner John Marshall, QC, said the skipper did not understand how people and equipment would effect the vessel's stability.
The Easy Rider went down in Foveaux Strait in March last year, with one survivor, while en route to the TiTi Islands, south of Stewart Island, for the start of the annual mutton bird season.
The TAIC report says at least one member of the crew had been drinking heavily and there were high levels of cannabis in another crew member and some of the passengers.
Too few life jackets were carried and a raft, which became entangled in the wreckage, could carry only half the people on the boat.
TAIC chief investigator Tim Burfoot said the Easy Rider sinking is one of the worst cases he's worked on.