For all the entertainment and recreational options a cruise ship might offer, its passengers tend to spend inordinate amounts of time eating, drinking, and resting up for the next meal. But when a stomach virus strikes aboard one of these boats, it’s like mutiny on the Bounty, but with intensive visits to the W.C. and no Tahitian backdrop.

So it was last week on the Ruby Princess, which set sail for the Caribbean from Fort Lauderdale on Jan. 29 and returned as scheduled on Sunday. Ninety passengers and 13 crewmembers on the boat contracted Norovirus, a contagious bug that can cause vomiting and diarrhea for one to three days, a Reuters story on the voyagers’ tribulations points out. The seafaring misery in this case, however, likely was shared by those ashore at Princess Cruises, Ruby Princess’s operator and a subsidiary of Carnival (NYSE:CCL), operator of the Costa Concordia, which shipwrecked on Jan. 13 off the coast of Italy, killing 17 people. Fifteen Costa Concordia passengers are still missing.

As maritime nightmares go, this obviously is among the worst, and, as Reuters notes, it is expected to impact the operations not only of Carnival, which said the disaster in Italy would trim profits this year by $155 million to $175 million, but also of competitors such as Royal Caribbean Cruise (NYSE:RCL), which warned last week that it would face a sharp drop-off in new cruise bookings.