The designs that are the basis for shipbuilding are among the most complex schematics in technical terms. Naval architecture firms will provide these designs for their clients. The difference between naval and marine is significant here, since marine means work for the civilian sector or private enterprises needing ships.
All types of companies working in shipbuilding need either their own in house marine or naval architects or employ outsourced firms or consultants. These are typically storehouses of knowledge of sea and sailing. The architecture is unique to vessels that are powered by large engines and need to float and run sea distances.
Designs are often classified into the types of vessels which are planned for or being studied. Architects usually work or do their stuff only when contracted by certain firms. The study and the resulting designs will cost some money to do, and it is more like a plan for factories or plants because ships need to have a complete system keeping it afloat and supporting the lives of crews and passengers.
Thus the largest vessels often have the features of both home and communities. They have to serve the needs of crews or any group of occupants, but these features will have to be designed in such a way as to make the most use of space. These also need unique dimensions and installations relevant to the limited space and perhaps how a vessel floats.
Toilets for instance, usually are flushed out direct into the ocean or use chemical tanks that cleanse waste before releasing it into the sea. The most important parts are the engines and the ballasts, and the control structures like the bridge and other installs that are scattered around the vessel. Also, the total structure is actually formed as entire unit in building yards.
These need to be so designed to create specific measures for excellent floating qualities, speed and the capacity to carry its own weight as well as transport or passenger loads. The largest of ships need to have complex studies which are divided into several phases and parts. Engines for instance are addressed independently.
These not only require studies by architects, the specs are also submitted to manufacturers or the yard itself. The engines are often built along with the keel and ship body itself. But this is built alongside, designed and overseen by other experts in marine engineering specific to this mechanical system.
Engine manufacturers can also build up a set of engines and propellers that are made to order. They might be independent of the shipbuilding yard. They deliver on their machines and products on the date required when the hull and various wells for the engine parts and installs are ready to be set up.
Designers and architects here work first before anything is accomplished. Their firms often have overall management for any project. The yards will be part of the building process alone, but sometimes naval architects are also employed as a special department by the firms running shipyards.