One of the highest cost of building the ship refers to the ship’s propulsion system. It is therefore very important to know all the types and specificities of propulsion systems for the optimal selection. This paper presents the conventional and the combined propulsion systems, where are briefly given their characteristics and specificities. Special attention is given to the combined propulsion systems, whose extensive use is still under expectation. At the end, the paper discusses the cost calculation of a marine propulsion system of selected passenger cruiser and comparison to the possible alternative system.

Container transport by sea has almost doubled in the last decade. Accordingly, container ships’ size has increased significantly, and the latest container ships carry up to 24000 Twenty-foot Equivalent Units (TEU). In the near future, the appearance of container ships with a capacity of 25000 TEUs can be expected on the market, because the design is already available. It is known that 10-12% of transported containers contain International Maritime Dangerous Goods (IMDG) cargo. The above stated reasons directly impact the frequency of container ship fires in cargo spaces. According to the Insurance Companies, fires occur on average every two months, and this is a growing problem of container transport by sea. In this paper, 23 fires in the cargo area, either in cargo holds or on deck, were analysed. The analysis results determined the most common causes of fires and have shown that the current fire protection systems on container ships are ineffective. It is unacceptable that firefighting systems’ inefficiency results in the loss of human lives, abandonment of vessels, environmental pollution, and extensive property losses related to cargo and ship structure. Due to all the above, it is necessary to continuously work on new regulatory and technical solutions to improve the fire safety of cargo areas on container ships.

Long Range 2 tankers are the largest ships used for the transportation of petroleum products. Although more than 400 Long Range 2 tankers are navigating the world’s sea, many of the terminals, at which these ships discharge their cargo, do not utilize their discharging capacity to the full extent. This is due to the technological obsolescence of the terminal and the fact that these terminals are primarily designed to accommodate smaller tankers, such as Medium Range and Long Range 1 tankers. The reduced discharge capacity leads to longer ship stay in the port and increased air pollution due to the release of inert gas into the atmosphere since terminals unnecessarily insist on the continuous operation of the inert gas generator. This paper explains a possible solution to this problem by using environmentally friendly START/STOP operation mode of an inert gas generator using methods of analysis and synthesis, comparative methods and elements of the mathematical method. Environmentally friendly operation mode requires minimal modification of the software program and it is very easy to perform. This mode has a positive effect on reducing overall gas emissions and significant fuel savings.