Construction of Transportation Means - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 53

3.4.5.1 Double Bottom
Double bottom technology has been introduced in container ships first, later in
bulk carriers, tankers, and then in other ships. For this type of construction is the
reduction of corrosion, material fatigue, crack formation, overloads, and damage
especially important [ 72 ]. However, double bottom technology contributes to
higher manufacturing and operating costs and higher SFC.
3.4.5.2 Fast Mono Hull Concept
The fastest ships are catamarans because of the very low hydrodynamic resistance.
Fast mono hull designs cannot achieve the same maximum speed, but they are
more economical and can be used for all kinds of fast ships, such as fast passenger
ships, ferries, container ships, refrigeration, and Ro-Ro ships.
The optimal streamlined form and the specific smooth surface of the hull reduce
the resistance of waves below the waterline. Above the waterline the construction
increases the crossways stability and the usable space. Ever larger hulls are being
constructed with reduced specific weight through the use of high-strength ship-
building steel instead of normal quality steel. Furthermore, in fast construction, the
stern is optimized for the propeller to work at high speed.
In the shipping fast catamaran and mono hull constructions consume the highest
specific rate of fuel and emit the highest specific volume of exhaust gas pollutants
[ 73 ].
3.4.5.3 Common Structural Rules for Designing
and Monitoring Construction
Ships for the North Atlantic are expected to be in service for 25 years. Therefore,
hull scantlings and steel distribution must be constructed in accordance with the
Common Structural Rules (CSR) [ 74 ]. CSR does not require a radical change from
the existing rules, but it raises specific issues concerning structural strength, cor-
rosion, watertight integrity, and fatigue.
The CSR multi-purpose software supports the design and analysis of hull
structures and the cross-section of vessels. The main aim is to minimize the
additional amount of steel required. Computer software determines the scantlings
of all structural components automatically based on requirements for the vessel's
size, shape, weight, class, cargo load, and fuel consumption.