This was interesting and may well have impact for cruise ships in the general vicinity of the activity.
"To clear its path and reduce risks, scientists set up an exclusion zone for ships around the volcano. Recreational ships must stay at least 5 kilometers (3 miles) away from the summit of the volcano. Underwater or submarine volcanoes release intense amounts of gas into the sea during eruptions -- and at times in between eruptions during a process called degassing. Such gas bubbles lower water density and can cause ships to lose buoyancy and sink."
I'm not sure about anyone else but buoyancy is a top-of-the-list issue for me when it comes to cruising. What do you think?