APPLICATION OF COMPOSITES FOR SHIP STRUCTURAL PARTS

In the past, there were very serious casualties under the actions of extreme waves including loss of precious lives. There are cases like loss of M V Derbyshire (Faulkner, 2001) due to hatch cover failure in extreme weather conditions. Use of composite materials in marine fields as major or minor components off floating platforms is discussed in this paper. Application of composites on board ships reduces the self weight and lowers the position of vertical centre of gravity of the floating vessel. There are advantages in using composite structures in marine environment. A link-span fitted with a composite deck and the feasibilities of using composite for hatch covers of bulk carrier ship is described in this paper. In the case of bulk, carriers, failure of hatch cover especially in the forward part of the vessel leads to flooding of the forward cargo compartment and occasionally results in fatal casualty. The foremost hatch cover and the next one within 25% length of the vessel are prone to the impact by shipping of green water. The loss of hundreds of bulk carriers with the precious lives is nightmare to both designers and insurers. Though rare, the extreme wave heights are responsible for the failure of bulk carrier ships. Deficiency in the scantling of bulk carrier hatch covers is brought out in this paper first and suggestions for better designs are proposed. Suggestions to use better material having higher strength to weight ratio are proposed. With the increase in the section modulus of bulk carriers, the position of vertical centre of gravity of vessel goes up and that is not desirable for commercial ships in many aspects. Likely point loads due to extreme waves are found out and analyzed arriving at the structural response. The results have spin-offs in the naval context as naval ships need high strength material in the structural part above the main deck.