Tongala is ship number 11 in a series of 12 vessels from MHI. The most prominent improvements over Torrens, the lead vessel delivered in 2004, include electronically controlled, Tier II main engine, improved fuel oil system, water ballast treatment system. Cargo intake is somewhat reduced to give space for protected fuel oil tanks.
The vessel is arranged with engine room aft, mooring decks forward and aft on deck 7, living quarters in two tiers on the weather deck. Wheelhouse to be arranged forward to improve visibility.
Pipe tunnel is arranged in double bottom with main lines and valves for water ballast, bilge and fuel oil. Deck no 7 is watertight to provide a second watertight barrier, in addition to the freeboard deck (deck 5). Fuel oil in protected deep tanks forward and aft, from tanktop to deck 3. Pilot ladder, gangway, bunker station to be arranged on deck 5. Rescue boat to be arranged in a recess on deck 9, port side to ensure reduced and thus safer lowering
Cargo hold and handling
The cargo hold is laid out with single pillars from aft to forward,
with a longitudinal span of 10.8 m. Four liftable decks offer
flexibility and good utilization.
Cargo handling equipment delivered by TTS (stern ramp and
internal ramps) and Kawasaki (liftable decks).
Hoistable (hydraulic) ramps and covers provide onwards
access to all decks and allow simultaneous loading and
unloading of all decks.
Ventilation by means of forced supply fwd and natural exhaust
aft for 10 and 20 air changes per hour is arranged with
remotely controlled fire dampers.
Tank Capacities and Arrangement
All tank capacity figures are approximate and 100% full. 7 storage tanks from 300-900 m3 are provided for heavy fuel oil. Separate filling & transfer lines are arranged for HFO and MDO.
WB tanks 10,277 m3
Fuel Oil tanks 7 tanks, 3,692 m3
FO service & settling tanks 4 tanks: 222 m3
Diesel Oil tanks 2 tanks: 247 m3
DO settling & service tanks 2 tanks: 71 m3
4 HFO storage tanks can be converted to MDO to meet future
increased demand for MDO (in Emission Control Areas etc),
bringing the total MDO capacity to 2,300 m3.
Fresh Water tanks (two tanks) 2 tanks: 310 m3
Main engine and Auxiliary Engines comply with IMO Tier II requirements for NOX-emissions. Fuel oil is carried in protected deep tanks. Fuel oil system,
including tank arrangement and piping, is prepared for gradual switch from HFO to MDO in the near future, to comply with various global and regional emission regulations.
Coriolis type fuel flow meters enable more accurate measurements of fuel oil consumption and thus follow up of performance. Mitsubishi’s patented stator fin fitted aft of the propeller on the rudder horn reduces propulsion power and fuel oil consumption by abt. 2%.
The underwater hull is coated with Nippon Paint’s LF-Sea antifouling
to reduce frictional resistance and thus fuel oil consumption.
The vessel is equipped with a Pure Ballast ballast water treatment system from Alfa Laval.
Dual speed sea water cooling pumps helps to reduce power
consumption at low engine loads.