The sky?s the limit

With growth rates of 8% per year being predicted, the current slump in cruise ship orders could only be short term ? but what direction is design heading in?

When asked what would be next after Queen Mary 2, Gerry Ellis, director of new builds for Cunard Line, told The Motor Ship: “I think the future of cruise ship design will follow two routes ? one is the successively growing trend for mega cruise ships in which larger and larger ships will be produced up to a yet to be defined limit, but possibly constrained by drydock and port facilities. The other is that of the platform base so successfully implemented by Carnival Corporation.”

However, there could be a third limit ? that of passengers willing to travel on ever larger ships. Christopher Wright, president of The Mariport Group, points out that “the urge by shipowners to try and reduce unit costs has been a common theme for the last 40 years, but it is interesting that those companies that have recognised that bigger is not necessarily better have done very well in most areas of shipping”.

He explains that when the company developed the Great Northern concept, with the Great Lakes in mind, it was also driven by the survey work that showed 92% of cruise passengers preferred ships under 1,000 pax capacity and, 60% preferred vessels in the 200-600 pax range. He told The Motor Ship: “It is this disconnect between cruise management, to whom a lower unit cost is everything, and the passenger that is looking for a cruise experience rather than a floating convention, which prevents them seeing opportunities.”

However, will passengers be willing to pay a premium to go cruising on smaller ships? Probably not. The one thing that lower unit cost has done is to bring cheap cruising to the masses. While there is room for the specialist smaller ship, the big players are only likely to try to drive down unit costs in an effort to get greater numbers cruising.

While ports are likely to keep expanding facilities in an effort to make sure that the cruise ships don?t take their business somewhere else, the limitation on drydocking facilities could really become a hindrance. The Grand Bahama Shipyard, which currently has a number of cruise ship visitors, has a lifting capacity of 150,000t in its floating dock no 2, which it claims is one of the largest in the world. The current Voyager class is already over 140,000t, the Queen Mary 2 150,000t and the new Ultra Voyager class 160,000t. Yards such as A&P?s Southampton yard, which has drydocked the QE2 in the past, will find the Queen Mary 2 too wide for its King George V dock and even Lloyd Werft will not be able to dock this new breed of Leviathans.

One of the biggest things affecting cruise ship design and that of other ship types for many years has been the width of the Panama Canal. The maximum beam of 32.2m allowed in the locks has made ships long, narrow and high and has restricted the space on board. However, the Panama Canal Authority is now investigating the construction of a third row of locks, with impressive dimensions. The increased size is not being introduced because of the needs of the cruise industry but to enable the large container vessels built today to transit. With the new lock dimensions of 425m long, 60m wide and 18.3m depth compared with the current 294m long, 33.5m wide, 12.5m depth, very large cruise ships could transit from the Caribbean to the West Coast. The new locks are scheduled to be completed by 2010. This could open the door for a number of wide body cruise ship designs.

Stay at home

However, size is not all and Kvaerner Masa Yards has been putting forward a number of new concepts, such as the vacation at home. In this concept customers are offered a number of alternatives as even a short cruise of three or four days might be too long away from work or other obligations. The vacation entertainment could come to the customer instead of the customer having to travel. A floating entertainment centre with theatre, large performance shows, circus, games, food and dining services could visit the passenger port terminal and offer a vacation while staying at home. Kvaerner Masa Yards explains that the ship is like a cruise ship, but has no passenger accommodation, only public spaces. The crew and staff live onboard and travel with the ship from port to port. However, the entertainment onboard must be something not found ashore in most cities.

The need for speed

While fast cruise ships are not new as Blohm + Voss built two fast monohull cruise ships, making a Panamax vessel capable of 30 knots is something completely different. Kvaerner Masa Yards explains that to reduce the time needed for the transfer from a cold weather port, more machinery power is needed.

In addition to the typical diesel-electric or gas turbine-electric propulsion with twin pods, a booster power plant with two additional gas turbines directly coupled to water jets could be used. The total propulsion power would then be 75-80 MW, which gives a Panamax cruise vessel a service speed of 30 knots. The transit time from New York to the Bahamas would then be about the same as from Miami to Hispaniola or San Juan in a 20-knot vessel. However, to reduce fuel costs, the lower power pod propulsion would be used on the inter-island legs.

In this concept, the added cost to the cruise ticket will be roughly the same as for the flight ticket to Miami. However, if a faster transit is needed the passengers must be prepared to pay a premium rate.

Cruise ships use a full displacement type hull form, which can operate at speeds corresponding to Froude Numbers below 0,35. For example, a cruise ship of Panamax size with a waterline length close to 300m could operate at well above 30 knots. Kvaerner Masa Yards says that several high-speed RoPax ferries with a length of 200m have been built for operation at a speed of 28-30 knots. However, the increase in speed demands more propulsion power. The relation between trial speed and power for cruise ships of different sizes is shown (in diagram). A service margin of between 15-20 % should be added for wind and waves in normal service conditions.

Another market that the Finnish shipbuilder sees opening up is that of the cruise ferry. The cruise ferry concept is well established both in northern Europe and in the Mediterranean.

The ships operate on short international overnight routes with many of the passengers on a round trip returning on the same vessel. The cruise ferries can also carry private cars, mobile homes and lorries. This kind of service has been proposed for Cuba, if and when the trade is open for Americans. However, Kvaerner Masa Yards believes that these ferries could also operate to San Juan carrying “snow birds” in mobile homes south for the winter and back north in the spring.

Visitors from South America are likely to want to bring their own cars to Florida, as it will enable them to bring larger and heavier goods back home.