CharterWave Special Report

Date posted: February 2008

It is difficult to define “the environment” in the context of cruise ships and charter yachts. There are the world’s waters, where cruising of course takes place. There is also the air, which captures exhaust that ships and yachts “spit out” as they make their way.

For the purposes of this CharterWave Special Report, we took a look at both. As you read each of the following sections, we hope you will agree that chartering a yacht does far less environmental damage than booking a week onboard a cruise ship.

The World’s Waters

We want to be clear right up front and say that we do not know how much of the waste generated by ships and yachts actually gets dumped at sea, versus pumped out for proper treatment. All we are able to say for sure is how much waste is being produced, and thus how much it is possible for cruise ships or yachts to dump into the world’s waters.

The average cruise ship generates about 210,000 gallons of sewage each week. That’s according to Green Daily, a website that reports exclusively on environmental issues.

A typical cruise ship holding 3,000 passengers, according to Green Daily, also produces about a million gallons of gray water each week from showers and laundry facilities, as well as about 25,000 gallons of oily bilge water.

That’s a total of about 1.23 million gallons of “wet waste” being produced by each typical cruise ship, every week.

CharterWave compared these numbers against charter yachts by looking at sewage and gray water holding tanks, which are designed to hold at least a week’s worth of material. We chose a motoryacht from the largest segment of charter yachts available, 150 feet and larger, because they have the biggest holding tanks and are thus likely to fare the worst in our comparison. We don’t want to be accused of giving the yachts an unfair advantage.

Our “test boat” was the 164-foot motoryacht Mine Games. Its sewage holding tank can store about 300 gallons of waste. Its gray water tank has the same capacity. This means that when the yacht’s “wet waste” tanks are full, there is about 600 gallons of material onboard. We assumed that those tanks would fill up once a week, to make an even comparison against the cruise ship figures.

At that apples-to-apples rate, Mine Games would have to do 2,050 weekly charters to generate as much wet waste as a single cruise ship does in a single week. If you factor in oily bilge water, you might knock a bit off that number, but certainly not enough to make a dent in the figures.

Since yachts typically offer about a dozen weeks of charter each year, this particular motoryacht would have to offer charters for more than 170 years in order to produce as much wet waste as a typical cruise ship does in a single week.

That’s right: It would take almost two centuries for one of the world’s larger charter motoryachts to generate as much waste as a cruise ship does in a single week.

You might argue that cruise ships carry more people, and thus make more waste faster, so we looked at those numbers, too. When we divided the average amount of cruise ship waste by the typical number of passengers and crew (3,000), we came up with about 410 gallons of waste being generated per person, per week. The same calculation for our sample yacht, with the maximum 12 passengers plus nine crew, yielded just 29 gallons per person, per week.

And we would remind you that our sample yacht is one of the bigger motoryachts available for charter anywhere in the world. The comparison of “wet waste” generated by a cruise ship to, say, a 50-foot sailing yacht would be almost laughable.

The Air We Breathe

The Telegraph of London ran an article last month titled “Flying Three Times Greener than Cruising.” The focus of the story was on emissions of carbon dioxide, which cruise ships reportedly emit three times more of than airplanes.

As an example, the Telegraph cited statistics from a Carnival cruise ship. The long and short of those numbers was that on a per-passenger basis, cruise ship passengers were leaving a carbon footprint more than 36 times that of people flying onboard a Boeing 747 jet.

We here at CharterWave tried to put those figures into context in comparison with charter yachts. We leaned on the research of charter company Camper & Nicholsons International, which has been working for some time with the CarbonNeutral Company to help charter clients offset the amounts of carbon dioxide burned during yacht charters. We also stood on the shoulders of research done by CharterWave sponsor BoatBookings.com, which has an entire section on its website devoted to helping charter clients offset their vacation’s carbon emissions.

What we found is that even onboard the largest motoryachts available for charter, those larger than 150 feet that require the most energy to run, charter yachts dispel less carbon dioxide into the air than cruise ships do.

Here are the hard data.

Carnival Cruise Lines says its ships release an average or 712 kilograms of carbon dioxide per kilometer. That’s about 2,300 pounds of carbon dioxide per mile.

We took a typical, six-day itinerary advertised by Carnival, running round-trip from Fort Lauderdale with stops in Key West, Grand Cayman, and Jamaica. That’s a total of about 1,677 miles, producing about 3.85 million pounds of carbon dioxide emissions.

Then we looked at another of the world’s larger motoryachts, the 153-foot Flinders. We assumed that it would cruise four hours per day for six days, which is about the most hours per day that any charter yacht typically cruises. We punched those numbers into the carbon-emissions calculator on the BoatBookings.com website and determined that during a six-day charter, Flinders would emit 21,702 pounds of carbon dioxide.

Thus, the same number of days spent chartering onboard this 153-foot motoryacht would emit just one-half of one-percent as much carbon dioxide as six days' worth of cruising onboard a typical cruise ship.
To be fair, we also looked at these numbers one other way, by taking into account that the cruise ship carries about 3,000 people while the yacht would carry no more than 21, including crew. For those same itineraries, the cruise ship would emit about 1,280 pounds of carbon dioxide per person, while the motoryacht would emit about 1,085.

That’s not as large-scale a difference as the wet waste numbers, and it in fact shows that on a per-person basis, chartering larger motoryachts can do almost as much damage to the air as cruise ships.
But it is difficult to ignore the cumulative effect of multiple cruise ships dumping close to 4 million pounds apiece of carbon dioxide into the air every week, especially when compared with the fraction of that amount that motoryachts produce on a cumulative level. Even with similar per-person emissions, Flinders would have to charter a dozen weeks a year for close to 15 years to do the same carbon dioxide damage as that typical cruise ship does in a single week.

Also, according to the BoatBookings.com calculator, the entire week’s worth of carbon dioxide emissions produced by the motoryacht Flinders in our scenario could be offset by a purchase of about $150 in carbon credits. As the yacht’s weekly base rate is $125,000, this is a negligible expense.

Further to that point, Camper & Nicholsons International advises its clients that for the largest motoraychts in the world, guests can offset their carbon footprint by purchasing $2.60 in credits for every nautical mile traveled. Onboard small sailing yachts, the cost is just 37 cents per nautical mile.

That last point bears repeating. The yachts in our examples, Mine Games and Flinders, are among the larger charter motoryachts in the world. If you book a sailing yacht or one of the new-to-market hybrid catamarans, your per-person carbon dioxide and "wet material" emission rates will drop even further beneath the cruise ship norms.--Kim Kavin