Engineering a ship is very different from designing a building. First of all, each vessel is basically a machine composed of many smaller machines, where each gadget and cubic foot of space has to fulfill a particular purpose. There's little room for waste.
At the end of the day, the goal is to make a profit, not just float. If a particular ship design can operate with a slightly smaller crew, a little less maintenance, or be a tiny bit better at its job, it may well be considered a home run.
Marine engineers also need to understand concepts unique to the maritime environment, like corrosion and wave action, that other engineers rarely even think about. Safety and ruggedness are especially important: the failure of any one system can send the vessel back to port or worse. And it's not like the occupants can simply walk away if something goes wrong.
For these reasons, many universities offer specialized courses in marine engineering. Naturally, most are located near major ports: Delft, Southampton, Trondheim, and Athens all have schools with excellent reputations in this field. This leads to close cooperation between industry and academia, including internship opportunities.
In addition to the science and math courses found in all bachelor's of engineering curricula, future marine engineers study naval architecture, wave mechanics, hull hydrodynamics, and other subjects pertinent to their field.
Marine engineers deal not only with oceangoing vessels but also port facilities, fixed aquatic installations like oil rigs, and ship subsystems (propulsion, communications, and so on). Most marine engineering degrees will provide you with at least the basics needed to understand these. It's not a bad idea, however, to plan on also getting a separate qualification specifically in mechanical or electrical engineering, or a related field like marine logistics or oceanography. By studying in Europe, you may even be able to afford to!