Leaders of the Rail, Maritime and Transport Union (RMT) are in the Isle of Man today (Tuesday) for a summit to discuss employment protection for seafarers.
Bob Crow and his number two Steve Todd will speak at tonight's public meeting, along with Mark Dickinson, who is leader of the officers' unions Nautilus, and President of the Isle of Man TUC Angela Moffatt.
It's been organised in response to the threat to Steam Packet jobs posed by the rival Mezeron freight service to Liverpool.
Although that has since shut down, unions want to keep up the pressure, to prevent skilled, local maritime jobs being undercut by other foreign-crewed operations.
Last week, RMT national secretary Steve Todd said unions couldn't afford to take their eyes off the ball:
The public meeting is at the Empress Hotel in Douglas at 7.30pm.