Dear readers, Welcome to issue 41 of the Scientific Journals of the Maritime University of Szczecin. The scope of our quarterly is concentrated around sea-related aspects. In this issue there are four papers devoted to an overview of solutions in terms of renewable energy, including sea wind farms, tidal and wave energy conversion, and three papers on ship propulsion systems modelling. You cannot miss a very interesting article in the area of marine traffic engineering which describes the port basin as a waterway system component. What is more, there are a few papers on selected aspects of tribology, marine traffic safety, cartography and seamen manning agency operation. As for readers – please do not hesitate to send us any comments and suggestions concerning the development of our magazine. All authors, on the other hand, are welcome to send their manuscripts. To access the electronic version of the current and back issues, I encourage all the interested to visit the website available at http://journals.am.szczecin.pl.

This article draws attention to the problems of maintaining fuel injection pumps of marine diesel engines in the conditions of use of residual fuels whose quality is steadily deteriorating, and also burned under engine’s reduced load and in situations where the international rules require a temporary change over into distillate fuels. The analysis of tribological processes occurring in hydraulic precision pairs of fuel injection pump such as barrel-plunger was presented and the types of occurring wears were discussed based on author’s own operational experience. There was pointed out the need for additional methods of verification / evaluation of technical condition using of technical diagnostic methods. Introduction by the International Maritime Organization (IMO) and the ratification by the associated countries, the rules relating to the control of emissions in special areas called Emission Control Areas (ECA) through changes in the International Convention for the Prevention of Pollution from ships: MARPOL – Annex VI, not only raised the operating costs or forced to ship owners / managers to comply with the provisions of the Convention, but above all had an impact on the operation of ships. It necessitated the use of fuel oils with low sulfur content called low-sulfur fuels, and in many cases, has ruled out the use of residual fuel to distillate fuels

Legal and economic aspects connected with generating electricity from waves are discussed and a classification of wave energy converters is shown. The study discusses selected technical solutions generating electricity from sea and ocean waves. Research directions of the Maritime University of Szczecin, Poland, are presented in terms of energy conversion from wave energy into electricity and using sea wave energy for coast protection against waves. The potential of waves as a renewable energy source (in Europe and outside) is evaluated and problems connected with implementing wave energy conversion systems are outlined. Increasing demand for energy in highly developed countries, depletion of accessible fossil fuels, ecological requirements on generation of renewable energy and political situation demanding independence and energy safety policies result in real search for new, effective methods of energy generation from renewable sources

Seas and oceans show variations in water levels caused by tides and continuous flow of water in the form of sea and ocean currents. Tides are most visible close to the coastline – tide parameters (water speed or change in sea level) allow construction of installations producing electric energy. Sea currents – superficial and deep are characterized by means of constant speeds and directions. Therefore energy retrieval from these elements of sea environment looks very promising. The article presents basic information on tides and currents useful for designing hydroelectric power plants. The already constructed hydroelectric power stations are also presented here together with several design solutions of future such installations. Two basic elements of sea environment: air and water are in constant motion throughout a major part of the year. Air travels over the sea surface in the form of wind, and water in the form of sea currents and tides as well as waves (however themovement of water particles is here totally differentthan in sea currents or wind).

Wind is such an element of sea environment, from which it is relatively easy to obtain energy. Wind parameters over both seas and oceans are more favorable than those on land (due to variability of landform features). Moreover, also sea wind turbines exercise comparatively smaller negative effect on people than on land. Therefore, sea wind farms are ahead of us, as further development of wind energy. The article presents basic parameters of wind turbines, possible installations on sea bed, as well as future designs of large floating sea farms. The article presents also an example of design analyses of wind turbine, using computational fluid dynamics (CFD).

The system of port waterways has been defined herein as a composition of three subsystems: approach area (port basin), quay and its equipment, navigational (determination of ship position and speed). Besides, the author defines the state vector of conditions for safe operation of berthing ships. Described are interrelations between parameters of port waterway system and the state vector of safe operation of berthing ships. Differences have been specified between sea waterway systems (fairways, harbour entrances, turning basins, anchorages) and systems of port waterways (port basin, lock).

Seas and oceans show variations in water levels caused by tides and continuous flow of water in the form of sea and ocean currents. Tides are most visible close to the coastline – tide parameters (water speed or change in sea level) allow construction of installations producing electric energy. Sea currents – superficial and deep are characterized by means of constant speeds and directions. Therefore energy retrieval from these elements of sea environment looks very promising. The article presents basic information on tides and currents useful for designing hydroelectric power plants. The already constructed hydroelectric power stations are also presented here together with several design solutions of future such installations. Two basic elements of sea environment: air and water are in constant motion throughout a major part of the year. Air travels over the sea surface in the form of wind, and water in the form of sea currents and tides as well as waves (however themovement of water particles is here totally differentthan in sea currents or wind).

The article presents the technical aspects of Digital Elevation Model (DEM) and Digital Surface Model (DSM) built on the basic of Very High Resolution (VHR) data to create orthophotomap in a rapid mapping mode. The final part of the paper is accuracy assessment of orthophotomap built on the same elevation models which were used in a rapid mapping way. In the article were using aerial photography’s gained from digital camera UltraCam Xp by Vexcel. The spatial resolution of this images is 0.10 m. Example data of Gazoport in Świnoujście were processed using photogrammetry software Agisoft PhotoScan. The usefulness of both DSM and orthophotomap products were achieved by cross calculating mean errors. Orthophotomap created in a rapid mapping way, with minimum set of images, was built across using Ground Control Points (GCP). The source of GCP points was the Polish Spatial Data Infrastructure Geoportal. Check points were measured using both geoportal and Global Navigation Satellite System (GNSS) in the Real Time Kinematic (RTK) mode.

While the ship is sailing on waves the relative motions occur which result in propeller emergence, and as a consequence – propeller thrust reduction which results in a decrease in the ship’s speed. Propeller emergence is also accompanied by the decrease in torque values, with which the propeller affects the marine engine. The article presents a simplified method for calculating the decrease in torque of the propeller during ship motion on a regular wave together with the obtained results for various ship sizes and propellers

Ships’ hull usually works in a hard environment caused by static forces and permanent dynamic loads. Modeling of dynamical reactions could bring information to the designer for recognizing the level of hazard for hull structure and propulsion system. A paper presents a proposal of identification of a degree of hazard the ships hull forced from underwater explosion. A theoretical analysis was made of influence of changes of hull structure in vicinity of shaft bearing foundations. The main problem of naval vessels is a lack of dynamical requirements of stiffness of the hull. Modelled signals and hull structure were recognized within sensitive symptoms of three sub models: model of hull structure, model of impact and model of propulsion system. All sub models allow testing forces and their responses in vibration spectrum using SIMULINK software.

The scope of this article is to analyze and evaluate the activity of the companies providing placement services for seafarers in Poland. For the intended purpose the study of legal conditions of employment of seafarers on ships was conducted – both national legislation and implemented in August 2013 Maritime Labour Convention (MLC 2006). Farther examination were subjected number and range of activity of all located on Polish area companies providing placement services for seafarers. As a example to analyze the industry manned agency Polaris Maritime Services Ltd. in Szczecin was served, which provides intermediary services in employment of Polish crew for ship owners from around the world. Verification of data from the company and those obtained through a survey allowed for evaluation of situation seafarers taking up employment via an agency and compare it with the situation of those sailors who alone are looking for a job in foreign shipowners alone.

The introduction to the Fault Tree Analysis has been presented in this article. Selected publications on the Fault Tree Analysis have been listed. The usefulness of the method in marine engineering application has been indicated. Reliability testing facility has been presented, that is typical two-stroke, slow-speed ship crosshead Diesel engine intended to power the ship. The way of creating system model with the Fault Tree Analysis application has been presented. Reliability structure of tested engine has been modelled using Reliability Block Diagrams, as well as the Fault Tree Analysis. Main tree describing the object reliability structure analysis and the sub-tree structure modelling crank system, subsystem of the cam shaft, cylinder exemplary system and turbocharger have been built. Qualitative analysis of the tree has been conducted – the minimal cut sets of the system has been determined. The directions for further research have been indicated.

The author discusses the impact of hydro-meteorological factors on the safety of fishing vessels through the presentation and discussion of the events that have taken place on the Polish fishing ships in the area of the Baltic Sea. Because it is not possible to compare the hydro-meteorological conditions on the ocean with the conditions of the closed sea, what is the Baltic Sea – the author has limited consideration to the South and the South-East Baltic which is the main area operation of Polish fisheries.It focuses mainly on criteria which have a direct impact on the safety of the fleet due to the size and nature of the work of fishermen.