New Urban Mobility Model
World Cup 2014 and Olympics 2016 visitors will be able to sail between venues on a fleet of seven new 2000-seat ferry catamarans designed specifically for Brazil’s upcoming international events by Holland’s CoCo Yachts. The new high-speed ferries are to be built by the Afai Southern Shipyard in China.
Henk van Herwijnen, General Manager of CoCo Yachts, says the ferries may carry 100,000 passengers every day, increasing to 150,000 during the international sporting events. They are scheduled to carry passengers between Rio and Niterói
The contract value of the whole project is said to be about US$110 million, including design and construction. Six of the ferries will burn standard marine diesel oil (MDO), and the seventh is to be equipped with dual-fuel engines capable of using MDO or liquified natural gas (LNG).
The ferries can travel at up to 18 knots, and the first ferry is due to be delivered in November of 2014.
Urban mobility on this scale demands a well-proven propulsion system that for the sake of the passengers is relatively noise-free, provides precision maneuverability, and takes up as little space as possible. Veth Propulsion, also of Holland, came closest to meeting these demands at the right price and landed a contract to deliver four counter-rotating Z-drive type engines for each of the new ferries, adding up to a total of 28 propulsion units.
It’s well-known that the Z-drive engine eliminates the need for a conventional rudder, replacing it with an underwater pod able to rotate through 360 degrees, which gives it the excellent maneuverability needed for a ferry.
Apart from a standard yet flexibly-mounted Z-drive design, Veth Propulsion’s unit has a counter-rotating system (CR) which combines high efficiency with small propeller diameters. Within a CR unit, both propellers rotate in opposite directions, so that the second propeller compensates for the turbulent flow of water caused by the first propeller. In combination they significantly reduce noisy and inefficient propeller cavitation. The manufacturers say that the optimum number of revolutions is about 20 percent less than a single propeller or two rotating in the same direction. These Veth Z-Drive propellers will be mounted on opposite sides of the hydrodynamic streamlined underwater gearbox, creating a more solid bearing and secure sealing system.
[This article was written by George Backwell and appeared on the Maritime Propulsion website. It was edited by CIE.]