How Cruise Ships Work

Cruise Ship Criticism

The Monterey, Calif., coastline. Monterey banned the cruise ship Crystal Harmony from the area after it discharged 35,000 gallons of wastewater into the area's marine sanctuary.
The Monterey, Calif., coastline. Monterey banned the cruise ship Crystal Harmony from the area after it discharged 35,000 gallons of wastewater into the area's marine sanctuary.
Briscoe-Knight/Getty Images

A floating resort packed with thousands of tourists and staff is bound to run into some trouble. The cruise industry has drawn the ire of many public health and enviro­nmental critics, not to mention law enforcement and legislators. Let's start with the environmental criticism first.

As you may expect, cruise ships generate several forms of pollution as they lumber through the seas.


  • Black water: Wastewater comprising human waste.
  • Gray water: Wastewater that comes from showers, dishwashers, sinks and other cleaning activities onboard a ship.
  • Bilge water: Water from the ship's bilge tank that contains engine oil and sludge.
  • Solid waste: Trash consisting of plastic and metal containers, usually ends up as incinerated ashes.
  • Hazardous waste: Cleaning chemicals, paints, solvents and dry cleaning chemicals that find their way into the gray water source or the bilge tank.

[source: Herz, IICRC]

An average cruise ship creates an estimated 90,000 gallons to 255,000 gallons (340,687 liters to 965,280 liters) of gray water, 30,000 gallons (113,562 liters) of black water and 37,000 gallons (140,060 liters) of bilge water daily [source: Herz]. Loose environmental requirements allow cruise ships to dump everything overboard except untreated and solid waste. Bilge water, gray water, as well as treated sewage and incinerated solid waste can be, and regularly is, dumped directly into the sea, so long as it is not within 3 miles (4.8 km) of the shore.

Ballast water taken on to stabilize the ship can also disrupt ecosystems. Ships inevitably fill their ballast tanks in one location and purge them in a different area, thus introducing new species of marine organisms into different environments. Much like kudzu when it was introduced to the U.S., foreign microorganisms can infect or kill native plankton, sea plants, coral, and fish.

From a public health perspective, disease outbreaks on ships are also a concern. Most of the major cruise lines -- Carnival Cruise Lines, Norwegian Cruise Lines, Celebrity Cruises and Princess Cruises among others -- have ­reported outbreaks, according to the U.S. Centers for Disease Control. The organism responsible for getting passengers sick usually is the norovirus, a common virus linked to gastroenteritis (the "stomach flu"). Norovirus infections spread quickly on a cruise ship due to the close quarters. To see the cruise ship inspections for a particular ship, visit the CDC Vessel Sanitation program Web site, which posts inspection reports.

Probably one of the most frustrating aspects of traveling on a cruise ship is the lawlessness. Several critics point out that cruise companies are more concerned with protecting themselves from liability. Cruise companies are hesitant to have legitimate security forces onboard ships for fear of lawsuits from the public.

Overcrowding also has become a deterrent for people taking cruises, especially as companies like Royal Caribbean, Cunard and Carnival push the limits of occupancy. Lines to participate in the onboard attractions keep growing as ships like the Genesis hit the water. Slated to arrive sometime in 2009, the Genesis, with a price tag of $1.4 billion, will be 1,180 feet (360 meters) long and will accommodate 5,400 passengers at double occupancy [source: AP]. These mobs of passengers can also overwhelm a port call destination. But cruise ship companies show no signs of stopping their quest to build the biggest ship.

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More Great Links


  • AP. "Royal Caribbean Ships Orders $1.24B Cruise Ship." CBS News. Feb. 6, 2006. (April 29 2008)
  • BBC. "QE2 departs on final world trip." Jan. 6, 2008. (April 22, 2008)
  • Bowman, Frank. "An Integrated Electric Power System: The Next Step." (April 8, 2008)
  • Cunard. "Queen Elizabeth 2 Ship Facts." (April 23, 2008)