Ferry completion ceremony held PASSENGER VESSELS


F


OLLOWING the successful completion of Osman Gazi-1 sea trials, a ceremony


was held for the 88m fast car ferry at Austal’s shipyard in Western Australia. Osman Gazi- 1 was due to travel to Istanbul to commence operations in April this year, and a second ferry was also due to launch in the same month (Ship and Boat International, January/ February 2007). Representatives from the Turkish ports


that the ferries will travel between attended the ceremony, as well as officials from the Istanbul Metropolitan Municipality, the buyer of the ferries, plus ferry operator management from Istanbul Deniz Otobusleri. A one hour sea trial took place after the


ceremony, with the vessel reaching speeds of up to 43knots, better than to the contracted 36knots. Official sea trials have also produced a higher than contract speed of 37.4knots, achieved at operating deadweight 90% MCR, with operational ride control system. The ride control system also features forward


T-foils and transom mounted interceptors providing dynamic pitch and roll stabilisation in higher sea states, for passenger comfort at high speed. Four MTU 20V8000 M71R engines were


installed at a reduced maximum rating of 7200kW at 1150rev/min, which facilitates low engine stresses, increases fuel efficiency, and enables longer intervals between engine overhauls. The ferry is designed to carry 225 cars, or


158 cars and 128lane metres for trucks and buses. The aft loading point includes an open bow above the forward turning area, allowing


Osman Gazi-1 has now completed sea trials.


combined vehicle and passenger ramps for fast port turnarounds. With two upper seating levels and two VIP cabins, Osman Gazi-1 has a capacity for 1200 passengers. On the lower level, passengers can utilise


Beurteaux tourist seating, configured in a mixture of standard rows and table settings, with two large kiosks providing catering forward and aft. Passengers on the upper level share a kiosk and are seated in the larger


Beurteaux 3000 series club seats featuring leather trim. In the VIP cabins Beurteaux VIP ocean lounges are installed. The vessel operates with a crew of 30


persons, and includes crew accommodation for 16. Passenger evacuation systems are installed and the ferry is classed to Germanischer Lloyd +100 A5 HSC-Passenger B OC3 notation, with the requirements for the Turkish flag.


Reducing noise on passenger ships I


NCREASED use of low-noise propellers and low-noise machinery onboard passenger


ships, such as diesel-electric propulsion and optimised air-conditioning systems, have assisted in reducing background noise levels in modern passenger ships. This has had the effect of diminishing the masking effect on sounds generated by human activity. So, while there may no longer be the same


amount of noise created by heavy machinery, there are now many smaller noise sources onboard. These sources are difficult to manage, as


the emitted noise levels can f luctuate, be intermittent, and are much closer to the most sensitive areas of the ship. The noise problem is particularly significant in large passenger ships and megayachts, requiring more efficient acoustic insulation. Sounds that are considered to be most


irritating are often based upon the recipient having to focus on information contained in the noise, even though it may only be a few decibels above the background level. For instance, music and voices can be just


42


as distracting as pure tones from hydraulic equipment, and intermittent operations like pool pumps. Small modifications make it possible to reduce a minor machinery noise problem, for example, fitting proper elastic mounting on pumps. Insulating cabins from noise effectively


has to be taken into consideration from design onwards. The complexity of the task constantly grows as the required sound insulation performance increases. Thought to be most effective at insulating against impact sound is the combination of a floating floor and a suspended ceiling, incorporating a large distance between the deck and the ceiling. Dimension and cost restrictions often do not permit this arrangement, therefore less efficient alternatives, such as visco-elastic flooring, may be used. Low-f requency music f rom large


loudspeakers, such as those used in a discotheque onboard a cruiseship, can be problematic to insulate against. The decibel level may not be high, but the noise can be very noticeable in adjacent cabins. Thick or


heavy materials are the most suitable for noise reduction, but again, economic or design restrictions could affect which components are employed. For new vessels, Lloyd’s Register’s Passenger


and Crew Accommodation Comfort notation specifies the noise level requirements agreed at the design stage, which is often followed by a general review of the noise and vibration control principles which have been applied. Detailed noise and vibration predictions are subsequently performed, regularly carried out in parallel with various component tests. On existing ships, measures can be taken


to decrease excessive noise and vibration by installing additional ventilation, heating, air- conditioning support, and resilient mounting underneath the main engine. Careful consideration of exhaust silencer design can also aid the reduction. Should these steps fail to solve the problem,


on-site sound insulation tests, excitation tests of the superstructure, as well as propeller analysis, can help to determine the most effective course of corrective action.


SHIP & BOAT INTERNATIONAL MAY/JUNE 2007


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