Laden & lossen zonder trossen: Alternatief afmeersysteem voor zeeschepen

Laden & lossen zonder trossen: Alternatief afmeersysteem voor zeeschepen

Fiktorie, E.H.G.

Civil Engineering and Geosciences

Hydraulic Engineering

2002-05-29

At the end of the 19th century a union was founded with members who owned a boat. For a living they brought the moorings of the seagoing vessels to the quay. As soon as the ship was moored the loading and unloading began. This was a slow process because they didn't have any big cranes and everything had to be done by hand. More then a hundred years later, in 2002, the mooring of the great seagoing vessels in the port of Rotterdam is still based on the same principle. With only this difference that nowadays time is money and so the process has to be accelerated if possible. This speeding up of the mooring process is the number one reason to start a research for the possibility to moor a ship without moorings. If there is an alternative way of mooring, what would it look like and what will be the advantages in comparison of the today's system. Some of the advantages are the reduction of the ships motion while berthed, a gain of time because of the faster mooring process and achieving a safer situation in the port by loosing the moorings. To find a new mooring system no option is excluded. However not all the systems found have the same feasibility, so they are not all worked out in a preliminary designs. By means of a Multi Criteria Analysis (MCA) only the 3 best systems out of the total of 5 are worked out. The first system is the hydrostatic mooring system. This one is based on a difference in water pressure over the width of the ship. The difference in pressure is caused by lowering the water level at the quayside of the ship. Due to a variation of the water level the exact force needed to hold the ship can be reached. The second system is de movable bottom. Here the ship is lifted out of the water over a certain height. Because of the friction between the ship and the lifting box the ship will stay at place. The most important issue here is the balance of the downward and upward forces. The third system works with (electro)magnets which hold the ship at the quay. The wind load to be taken by a system is calculated through the rules given in some publications of the Oil Companies International Marine Forum. The load by a passing ship in the harbour is taken from a simulationstudy for the Yangtzehaven at the Maasvlakte I in Rotterdam. The other boundary conditions needed for the design were also taken from the plans for this harbour. One of these conditions is the design vessel of the class Southampton++. This containervessel has a length over all of 382 metres, a width of 57 metres and a maximum draught of 17 metres. Through the summation of the wind- and passingloads the maximum load perpendicular to the quay is found to be 10.170kN. Parallel to the quay the load is 1947kN. While designing the three systems it is assumed that both these forces, perpendicular and parallel to the quay, has to be taken by each of the systems. The only movement of the ship that is allowed is the vertical one. This is caused by the tide of 2,09 metres en the vertical movement of the ship itself of 5 metres. With these given numbers a preliminary design is made of all three system in which the dimensions and an estimation of the costs are calculated. The same MCA as already mentioned is used to find the best system over all. The final opinion of this report is that the system with magnetism is the very best and even the far most cheapest system designed. With a price of just over €660.000,- this system will hold the designship at his berth. The complete system consists of 52 magnets with an area of 1 by 1 metre and a thickness of 0,25 metre. The magnets have a comb like shape through which the North and South pole appear alternating. By designing the magnet in the same dimensions as the ships hull the generated magnetic field will be kept inside the circuit these two elements make and will not put out any harm. Every pole needs 1200 windings to generate the right magnetic field. In total the winding need 35.000 meters of copper wire with a diameter of 2 mm. The magnetic field of 1 Tesla is generated by using a current of 384 V and 2 A. The needed power for each magnet is 768 W. The use of the current will be no problem because the cranes on the quay use 10 kV.

mooring systems

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Student theses

master thesis

(c) 2002 Fiktorie, E.H.G.