Different Stages of Ship Design Explained

Ship design is a convoluted process that involves multiple steps before the construction and fabrication work is commenced. When we use the word convoluted, it not only means complex but also a roadmap where with each stage, the methodology becomes more specific and refined and the shipbuilding process gets closer to being commenced. 

The various stages of ship design are discussed below.

Concept Design 

Unlike a car or a commercial aircraft, a ship is designed specifically based on the exact requirements of the mission and the optimization of various parameters and resources. 

This is the preliminary stage at the outset of the entire design cycle, where the vessel’s operational requirements are identified. Operational or mission requirements essentially mean a study of the exact yardsticks specified by the clientele (owner, operator, liner, company, authority, government, etc.) regarding how the vessel is suited to its purpose. 

For instance, in cargo vessels like tankers, bulkers, or containerships, the cargo capacity in terms of deadweight tonnage or TEU is specified, along with the type of cargo that is intended to be carried. Similarly, for passenger vessels, the number of passengers required to be carried in one leg of the voyage, along with the various suitable provisions, are detailed.

In addition, the other main mission requirements in terms of the voyage, like speed, range, conditions, and routes, are also specified in all kinds of ships at this stage. All these give a clear picture of what direction the vessel needs to be designed in.  

After identifying the mission requirements, a primary design of the vessel in terms of hull form, main particulars, cargo or freight stowage layout is envisaged along with the feasible metrics in terms of the type of stability criteria, propulsion system, engine options, fuel, manoeuvring systems like rudders, basic equipment like cargo cranage, and so on. 

The concept design of the vessel, including the hull-form design, involves the generation of line drawings or line plans that are combined with the principal requirements like the parameters or dimensions, stability design, a preliminary general arrangement layout, cargo or deadweight capacities, basic powering standards, tankage, primary engine selection, etc. 

Now, the preliminary design of the vessel under discussion is subjected to a techno-economic evaluation to assess the feasibility of the aforesaid design against two critical benchmarks: 1) Technical and 2) Economic. 

While in the preliminary stage, the vessel is designed keeping in mind the technical requirements intended, the technical assessment mostly involves running checklists of the concept design against standard set benchmarks that shed light into whether the apropos vessel can cater to the requirements for safety, integrity, and expected performance. 

In a more elaborate sense, the technical perspective mostly involves the following fundamental yet critical verticals: 

• Floats without sinking (lightweight + deadweight = displacement equivalent to buoyancy): Archimedes’ Principle 
• Whether the given design can float upright and remain stable under worst-case scenarios: Stability and seakeeping 
• Is spacious enough for the desired service (that includes the ability to sustain every aspect ranging from crew to cargo, machinery to equipment, fuel to effects, etc.): volume and tonnage deadweight available within the bounds of the given design 
• Is strong enough to withstand all forms of loading ranging from global to local, internal to external: Structural safety and integrity 
• Can cater to the speed requirements in reaching from point A to B without overshooting the cost index: Resistance, propulsion, powering, fuel efficiency  
• Can manoeuvre and steer as and when required: Manoeuvring and course-keeping 
• Has a build such that it can last for the desired amount of time without compromising on the functionality: Nature of material and construction 
• Latest environmental concerns that mandate it to adhere to the requirements of pollution 
• Compliance with the basic regulations and guidelines of IMO, classification societies, flags, and other concerned authorities encompassing all the above factors within set acceptable criteria for that kind of vessel. 

The other stage of the feasibility study involves assessing the cos…

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