VANCOUVER - The Transportation Safety Board's final report into the deadly capsizing of a whale-watching vessel off Vancouver Island is expected to be released next month.

An email from the board says its investigation report into the October 2015 incident involving the Leviathan II will be issued June 14.

Six people died and all 27 aboard were thrown into the waters off Plover Reef north of Tofino when a large wave hit the side of the vessel.

Safety board investigators have said most passengers and crew were on the top deck of the vessel's port side when the 20-metre vessel rolled and capsized.

Survivors described being thrown into the ocean without life jackets and grabbing hold of a single floating life ring while others reported swimming through oily water and rough seas to get away from the boat's rotating propellers.

At least 15 survivors and several family members of the six victims have filed lawsuits against the vessel's owner, Jamie's Whaling Station.