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Abstract
This thesis investigates and demonstrates a developed technique for the lightning protection of marine ships. This developed technique is named the Collection Volume Method (CVM), for the placement of either conventional or non-conventional lightning protection systems for ships.
Applying the (CVM) developed method using the conventional or non-conventional lightning protection systems was our key to find out the optimized placement of lightning eliminators to ensure that the most efficient lightning protection system (LPS) is installed on the ship. Our technique has proved to be the most efficient (LPS), since it presents the optimum solution for protection from the point of view of safety and cost.
It was well known that regular metal ships are rarely damaged by lightning strokes. Although these ships are frequently struck, the high conductivity of a large area of the metallic hull in direct contact with the water causes rapid dissipation of the electrical charges.
This is true in case of ordinary types of cargo or old military ships, recently fiberglass constructed ships or the new naval war ships which include rubber coated super-structure for both lowering weight and concealing the ships from radars are widely used nowadays. This has formed isolation between these parts and the hull.
When lightning occurs at any point of the upper mast or the ungrounded radio antenna, the metal antenna carries the electrical charge to the radio or the electronic equipments, which will get damaged. These ships can be protected from lightning by proper designed protection systems. Although lightning protection systems do not completely prevent lightning one hundred percent, they can drastically reduce the terrible damages.
This developed technique is used to identify the most suitable number and locations of the air terminals, based on the striking distance, horizontal protected distance and hence, the area of protection offered by each terminal. This developed technique enables the
designing engineer to determine the effective protection system with different eliminator heights and tYpes. It makes it easy to use optimum tYpe of protection with the minimum cost.
This novel technique was applied to a Corvette, Frigate, Destroyer, Air Craft Carrier as well as a Cargo Ship, and showed to be a very efficient means of lightning protection for these ships. For some certain design cases, a hybrid system was chosen to be most efficient and less expensive .