The largest Aquastrada

Italian fast ferry builder Cantieri Navale Rodriquez has received a $42 million order for an Aquastrada TMV 114 monohull, from Spanish roro ferry operator Armas.The largest in the builder`s range of 65-150m Aquastrada designs so far to be ordered, the 113.45m loa vessel will enter service in the Canary Islands in early 2000, carrying 800 passengers and 220 cars at a cruising speed of 44 knots.

The owner has specified six Caterpillar CAT 36l6 diesel main engines, each with an output of 6,000kW (8,158 bhp) at 1,000 rev/min, providing a total output of 36,000kW (48,255 bhp) arranged in pairs. Each pair drives three Lips waterjets through a two input/one output gearbox, which is double-speed to allow for 100 per cent redundancy if one shaft line fails. A central fixed booster jet will be flanked by two steerable jets.

This will be the first time Rodriquez has fitted Caterpillar engines to one of its newbuildings, as it usually uses MTU units. The owner specified Caterpillar because of previous experience with them, and also because they run on MDO rather than gasoil, which attracts a high tax in the Canaries.

A feature of the design will be two retractable 180 deg axis thrusters under the hull, one at the bow, and the other on the centreline approximately two-thirds back from the bow. The distance between the two thrusters means that the vessel can rotate on its axis using these units. This will provide the vessel with added manoeuvrability in harbour, and a get-you-home propulsion/steering capability in the case of total failure of the primary propulsion system. In case of failure of the primary jets, the fixed jet and thrusters can be used to steer and stop the vessel.

At full displacement, the speed with all six engines running at 100 per cent MCR will be 41 knots, and at 90 per cent MCR – 32,400kW (43,430 bhp) it will be 38 knots. With four engines running at 90 per cent MCR (21,600kW) the speed will be 30 knots, and two engines together will provide 22 knots at 90 per cent MCR (10,800kW). At medium displacement, operating six engines, the vessel`s speed will be 43.1 knots at 100 per cent MCR, and with four engines running at 95 per cent MCR, 41 knots.

The routes on which the vessel will run are affected by long 2.5-3m high swells, so the owner stressed the need for a stability system to counter this. All the Aquastrada designs are fitted with Rodriquez`s Navigational and Seaworthiness Management System (NSMS), and in the case of the TMV 114 this consists of two pairs of stabilising fins to control the roll; two T-foil wing systems located forward and aft, fitted with flaps on the struts acting as rudders; and a pair of transom trim tabs.

At speeds over 34 knots, the foils provide lift which reduces the vessel`s displacement. The position of the foils below the hull is critical, and on the TMV114 these increase the draught of the vessel to 5m, not a problem in harbours around the Canary Islands, says Rodriquez.

All the stabilising systems are controlled from a console on the bridge by means of a monitor and command panel. A monitor screen shows the ship`s motions – roll and pitch angle, vertical and transversal accelerations, as well as the angle of all the control surfaces. All sensors have 100 per cent redundancy.

All these data are analysed and compared with standard passenger comfort parameters, resulting in a colour display which indicates the percentage of motion sickness incidence (MSI) likely to occur among the passengers as a result of the vessel`s present motion.

Car decks Vehicles embark/disembark solely via stern ramps on the main car deck. Once aboard, access to the upper and lower garage decks are via internal ramps. Vehicle turning space at the forward end of the main deck is 14m, on the upper deck it is 15m, and 12m on the lower deck.

When carrying cars only, capacities on the main, lower and upper decks are 64, 45, and 91 vehicles respectively. While the main and lower decks, which each have a height clearance of 1.95m, carry only cars, the upper deck has a maximum height clearance of 4.65m which allows it to carry a mixture of 59 cars and 22 minibuses, or 77 cars and three buses.

A total of 928 passengers can be accommodated on the two public decks. Because of the shorter, and more frequent daily voyages which can be accomplished by the vessel, there is no need to provide restaurants or cabins for passengers, a factor which greatly decreases operating costs, says Rodriquez.

The vessel will be delivered to Armas in November 1999.