It's estimated that more than 10 million Americans will go on cruises every year.
Now after complaints of onboard assaults, thefts and even mysterious disappearances, Congress is investigating how safe these vacations are. A House Transportation subcommittee is holding hearings on cruise safety this morning.
Two hundred cruise ships dock in the United States, 198 of which are registered in foreign countries, exempting them from abiding by most U.S. laws and regulations.
This morning, Congress will hear testimony from passengers with stories about poor security and little accountability in this $30-billion-a-year industry.
Testifying will be Angela Orlich of Springfield, Mass., who with family and friends, went on a Royal Caribbean cruise in January 2003.
"We just thought that was the perfect thing to do, to see all the islands," Orlich said.
Aboard the ship, Orlich bought a scuba excursion in Cozumel, Mexico.
But once her instructor got her alone underwater, she says he started to sexually assault her.
"I started going towards the rope and I started to pull myself up on the rope, and he was pushing me down," Orlich said. "I started going up the rope again and at this time he started taking my bathing suit off, pulling it down."
She said he proceeded to shut her air tank off.
"I don't know if he was trying to murder me or what. But I got back up, I got to the top."
Orlich says no one at the cruise lines seemed to care. Royal Caribbean did not respond to ABC News' requests for comments.
In one three-year period, 178 cruise passengers reported sexual assaults and 24 passengers disappeared — like George Smith, who vanished during his honeymoon.
"We can't hold a funeral, and as, you know, as far as Royal Caribbean is concerned, they would merely have another drunk falling in the water — 'nothing we could do about it' — and that's not good enough," his sister Bree Smith said.
In March, Terry L. Dale, president and CEO of the Cruise Lines International Association, testified before Congress that "the cruise industry has a zero tolerance for crime. Our industry takes all allegations and incidents of crime onboard seriously."
But since that testimony, four Americans have disappeared and 41 have reported sexual assaults.
So Orlich has taken it upon herself to change things.
"I'm here in Washington," she said, "to help out other women, to make sure it doesn't happen to them."
Other victims testifying today will discuss a daughter who went missing, a son who went missing and a father who died in a fire on the ship. In every case passengers allege inadequate security and poor treatment by the cruise ship industry.