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1

A simplified method for calculating propeller thrust decrease for a ship sailing on a given shipping lane

100%
Zelazny K.
Polish Maritime Research
|
2014
|
tom 21
|
nr 2
During ship sailing on rough water, relative ship motions can be observed which make the propeller emerge from the water, and decrease its thrust as a consequence. The article presents a simplified method for calculating the thrust decrease and the time of propeller emergence from water for the ship on a regular an irregular wave. The method can be used for predicting the operating speed of the ship on a given shipping lane
2

An approximate mathod for calculation of mean statistical value of ship service speed on a given shipping line, useful in preliminary design stage

100%
Zelazny K.
Polish Maritime Research
|
2015
|
tom 22
|
nr 1
During ship design, its service speed is one of the crucial parameters which decide on future economic effects. As sufficiently exact calculation methods applicable to preliminary design stage are lacking the so called contract speed which a ship reaches in calm water is usually applied. In the paper [11] a parametric method for calculation of total ship resistance in actual weather conditions (wind, waves, sea current), was presented. This paper presents a parametric model of ship propulsion system (screw propeller - propulsion engine) as well as a calculation method, based on both models, of mean statistical value of ship service speed in seasonal weather conditions occurring on shipping lines. The method makes use of only basic design parameters and may be applied in preliminary design stage
3

Mean long-term service parameters of transport ship propulsion system. Part I. Screw propeller service parameters of transport ship sailing on a given shipping route

63%
Szelengiewicz T., Zelazny K.
Polish Maritime Research
|
2007
|
tom 14
|
nr 4
During ship sailing on a given shipping route in real weather conditions all propulsion system performance parameters of the ship change along with changes of instantaneous total resistance and speed of the ship. In this paper results of calculations are presented of distribution function and mean statistical values of screw propeller thrust, rotational speed and efficiency as well as propulsion engine power output andspecific fuel oil consumption occurring on selected shipping routes. On this basis new guidelines for shippropulsion system design procedure are formulated
4

Calculation of the mean long-term servic speed of transport ship. Part I. Resistance of ship sailing on regular shipping route in real weather conditions

63%
Szelangiewicz T., Zelazny K.
Polish Maritime Research
|
2006
|
tom 13
|
nr 4
Service speed obtainable by a ship in real weather conditions when sailing on a given shipping route, is one of the major parameters which have great impact on ship operation costs. The so far used, very ap-proximate method of service speed prediction based on “service margin”, is very little exact. In this paper a new method based on additional ship resistance dependent on mean statistical parameters of wave and wind occurring on a given shipping route, is presented. The mean long-term service speed is calculated on the basis of the calculated additional resistance and the screw propeller and propulsion engine parameters. Also, a new definition of service margin and a way of its calculation is presented apart from the results ofthe mean service speed calculation depending on ship’s type and size and shipping route
5

Calculation of the mean long-term service speed of transport ship. Part II. Service speed of ship sailing on regular shipping route in real weather conditions

63%
Szelangiewicz T., Zelazny K.
Polish Maritime Research
|
2007
|
tom 14
|
nr 1
Service speed obtainable by a ship in real weather conditions when sailing on a given shipping route, is one of the major parameters which have great impact on ship operation costs. The so far used, very approximate method of service speed prediction based on “service margin”, is very little exact. In this paper a new method based on additional ship resistance dependent on mean statistical parameters of wave and wind occurring on a given shipping route, is presented. The mean long-term service speed is calculated on the basis of the calculated additional resistance and the screw propeller and propulsion engine parameters. Also, a new definition of service margin and a way of its calculation is presented apart from the results of the mean service speed calculation depending on ship’s type and size and shipping route
6

Mean long-term service parameters of transport ship propulsion system. Part II. Propulsion engine service parameters of transport ship sailing on a given shipping route

63%
Szelangiewicz T., Zelazny K.
Polish Maritime Research
|
2007
|
tom 14
|
nr 4
During ship sailing on a given shipping route in real weather conditions all propulsion system performance parameters of the ship change along with changes of instantaneous total resistance and speed of the ship. In this paper results of calculations are presented of distribution function and mean statistical values of screw propeller thrust, rotational speed and efficiency as well as propulsion engine power output andspecific fuel oil consumption occurring on selected shipping routes. On this basis new guidelines for shippropulsion system design procedure are formulated
7

Calculation of the mean long-term service speed of transport ship. Part III. Influence of shipping route and ship parameters on its service speed

63%
Szelangiewicz T., Zelazny K.
Polish Maritime Research
|
2007
|
tom 14
|
nr 2
Service speed obtainable by a ship in real weather conditions when sailing on a given shipping route, is one of the major parameters which have great impact on ship operation costs. The so far used, very approximate method of service speed prediction based on “service margin”, is very little exact. In this paper a new method based on additional ship resistance dependent on mean statistical parameters of wave and wind occurring on a given shipping route, is presented. The mean long-term service speed is calculated on the basis of the calculated additional resistance and the screw propeller and propulsion engine parameters. Also, a new definition of service margin and a way of its calculation is presented apart from the results of the mean service speed calculation depending on ship’s type and size and shipping route
8

Numerical analysis of influence of ship hull form modification on ship resistance and propulsion characteristics. Part III. Influence of hull form modification on screw propeller efficiency

51%
Abramowski T., Zelazny K., Szelangiewicz T.
Polish Maritime Research
|
2010
|
tom 17
|
nr 1
After signing ship building contract shipyard’s design office orders performance of ship resistance and propulsion model tests aimed at, apart from resistance measurements, also determination of ship speed, propeller rotational speed and propulsion engine power for the designed ship, as well as improvement of its hull form, if necessary. Range of ship hull modifications is practically very limited due to cost and time reasons. Hence numerical methods, mainly CFD ones are more and more often used for such tests. In this paper consisted of three parts, are presented results of numerical calculations of hull resistance, wake and efficiency of propeller operating in non-homogenous velocity field, performed for research on 18 hull versions of B573 ship designed and built by Szczecin Nowa Shipyard
9

Numerical analysis of effect of asymmetric stern of ship on its screw propeller efficiency

51%
Abramowski T., Zelazny K., Szelangiewicz T.
Polish Maritime Research
|
2010
|
tom 17
|
nr 4
During designing the ship its designer tends to achieve as-high-as possible efficiency of ship’s propulsion system. The greatest impact on the efficiency is introduced by ship’s screw propeller whose efficiency depends not only on its geometry but also distribution of wake current velocity. To change wake current distribution and improve propeller efficiency an asymmetric form is usually applied to stern part of ship hull. This paper presents results of numerical analysis of wake current velocity distribution, performed by using a CFD method for a B 573 ship of symmetric stern and the same ship of an asymmetric stern. Next, the mean values of screw propeller efficiency in non-homogenous water velocity field were calculated for both the hull versions of B 573 ship
10

The influence of wind, wave and loading condition on total resistance and speed of the vessel

51%
Szelangiewicz T., Wisniewski B., Zelazny K.
Polish Maritime Research
|
2014
|
tom 21
|
nr 3
Optimising the ship route is one of the most important tasks related to the operation of the vessel, its safety, and economic aspects of transport. Nevertheless, from a mathematical point of view, this problem has not been solved yet sufficiently precisely due to very high complexity of the model to be used to describe the motion of the ship along the shipping line, and time- and space-dependent average values of statistical weather parameters recorded during ship sailing. That is why various approximate methods are used, which, among other procedures, utilize ship speed characteristics, having the form of very simple relations between basic dimensions of the ship and the expected speed decrease at the assumed weather parameters. The paper presents a new method of calculating the speed decrease depending on technical and operating parameters of a given vessel. A computer code prepared based on this method is used for research on forecasting ship speed in real weather conditions
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