Read the text and complete the sentences after it

The ship's hull must have sufficient strength to withstand the forces that will act upon it over a range of loading and sea conditions. Shipbuilding materials should meet strict requirements of modern ship design work and naval architecture.

Shipbuilding steelis the most common material. Modern ships are produced of specialized welded steels such as ABS Steels with good properties for ship construction. They are characterised by high strength, flexibility, manufacturability, weldability and reliability. Steels used in the domestic shipbuilding industry differ in high cold resistance, good welding characteristics and increased fracture strength. A new class of high-strength corrosion-resistant nitrogen-alloyed steels are being developed. Owing to difference of interaction of carbon and nitrogen atoms with atoms of iron, steel acquires unique physicochemical and operating properties such as high strength, flexibility, absolute corrosion resistance, non-magnetic behaviour and good welding characteristics. These steels cost no more than conventional ones due to rejection (or minimization) of expensive alloying elements like nickel, molybdenum, tungsten, etc.

Structural aluminium alloys with excellent corrosion resistance as well as aluminium-based composite materials became common use in construction of high-speed sea and river vessels as well as airfoil boats and hydrofoil ships. These alloys provide lightweight structures and good mechanical strength properties. At the same time such materials can be used for sound proofing in internal spaces, for shells and casings of various noisy instruments and machines. They are also sound-absorbing and vibration-absorbing.

Titanium alloys are common use in marine facilities owing to their properties.

Zinc is a rather corrosion-resistant material both in air and water. Zinc coating is used in corrosion prevention of metal surfaces in ship systems.

Copper alloys are widely used in shipbuilding industry due to their high corrosion resistance, strength under various loads, heat- and electro-conductivity.

Copper, copper-nickel alloys, aluminium, tin and silicon, bronze and brass are used for manufacturing water pipelines, pumps, propellers, heat exchangers and shaft lines (валопровод).

New polymeric and metal polymeric composite materials with glass or carbon fibres are finding more and more applications in shipbuilding. Their high strength, corrosion resistance, non-magnetic properties and production simplicity have defined the choice of reinforced-plastic materials for modern high-speed vessels. Superstructures, piping, propellers and deepwater submersible buoyancy modules – these are just a few items on the very long list of naval applications of the polymer-based-composites.

7. ____________________ with glass or carbon fibres are finding more and more applications in shipbuilding.