The Technology Of Jacket Platform Launch

With the development of the petroleum and gas resource in our deep sea areas, the transportation of the steel jacket to the deeper water areas will become more and more important. There are two methods for transporting the jacket, one is floating transportation, and the other is barge transportation. The launch by sliding from the barge is the usual way of installing the huge jacket.The method of the launch of huge jacket is generally sliding from the barge. Firstly, adjust the weight of ballast water in order to make the barge reach the scheduled draft and trim angle before launching, and then the jacket moves to the stern by using hydraulic-pressure pushing apparatus or the winch, at this time, the trim angle is increasing. When the trim angle is bigger than the friction angle, the jacket will glide along the skid beam ,until the position of the jacket's center of gravity is beyond that of the rocker arm's pin. At this time, the overturning moment is larger than the gross uprighting moment. The jacket is not only sliding but also rotating, and then gets away from the barge, the process of launching is over.In this paper, we will define the following factors: the draft of the barge, trim angle, longitudinal strength, immergence depth, ballast disposal and the motion of the barge, the strength of rocker arms and friction coefficient. We should choose the representative numerical value from each factor and make different combination to analyse the result and compare them, and eventually we get the optimum launch process.