Topic - 8 GENERAL ARRANGEMENT

The general arrangement of a ship can be defined as the assignment of spaces for all required functions and equipment, properly coordinated for location and access. The general arrangement represents a summary and integration of information from other divisions and specialties in ship design, intended to provide for all the necessary functions of the ship in the most efficient and economical way. This general arrangement of a ship gives a rough idea of how and in what way the arrangement of various decks as well as inside components is made. Generally this arrangement is done in co-ordination with the owner of the ship, and based on what equipment, with which the working personnel of the owner are familiar, based on that this general arrangement is done.

The efficient operation of any ship depends upon the proper arrangement of various components like cargo hold space, engine room, accommodation, ballast tanks, anchoring equipment and bulk heads etc.These bulk heads play an important role in maintaining water tightness and thereby preventing flooding.These also provide additional strength to the main deck or the weatherdeck. The bulk heads are of two types, longitudinal and transverse. Selection of number of these bulk heads must be made carefully. More number of longitudinal bulk heads may result in large amount of additional steel weight, which constitutes the light weight of the ship, thereby increasing the total weight of the ship.More number of transverse bulk heads may cause more stiffening and thus result in loss of strength. So, the number of bulkheads to be placed should be carefully selected.

The general arrangement represents mainly two views; profile view and main deck arrangement.

• Profile view:In profile view, we represent the accommodation area and the anchor handling arrangement, and if at all the ship is going to be located or moved near the yard or jetty, the fenders are also to be represented.These fenders are useful in preventing the direct contact between the ship hull and the yard or jetty wall.In addition to these we represent the tank division and other machinery equipment spacing.This spacing contains winch room, generator set room,pump room and the tank division involves double bottom tanks (ballast &bilge tanks), fuel oil tank etc.
• Main deck arrangement: In this, the arrangement of various deck components is depicted such as placing a crane, hatch door and access door arrangement.Further the arrangement of inside water ballast tanks is shown by a dotted line since these are located inside of the main deck.Arrangement of these water ballast tanks is very important for barges because, these water ballast tanks comes to necessity when to compensate the load acting during the loading and unloading operation of the jack-up structure.
• Sub deck arrangement: The arrangement in the sub deck is also shown. Generally in barges, the sub deck arrangement mainly consists of water ballast tanks, forward and after winch arrangement and the location of generator sets. The proper arrangement of these components ensures proper and desired results.