Internal Forces Analysis Of Mooring System

The mooring system is an important part of port constructions and the mooring chains is the core content of the mooring system. If we want to determine the gross length of the mooring chain and the blue print of location, first of all, we should know the internal force of the anchor chain. Therefore, the analysis of the internal force of anchor chain is an essential preparation for us to select the mooring system.Presently, the criterion method to get the strain of the anchor chain originates from the theory of catenaries. In practice parabola method is also introduced to approximately analyze the anchor chain. But systematic jobs haven't been done to estimate the range of error and application of the two methods, In this paper, we will find the differences between the two methods by specific calculation.To fully take the advantage of mooring chains, we introduce the type of anchor chains—the mooring chains with additional block. When the block is located in the middle of the anchor chain, it has proved that the horizontal strain of the anchor chains are up to the maximum value. So we come to the conclusion that we can prevent watercraft from swaying with a proper block, at the same time we can use a comparative shorter anchor chain and obtain the possible maximum strain.As for the two kinds of mooring chains, one with a part of which lying on the ground of the sea while the rest is suspended between the hawsehole and the ships or like this, the other without any part of it lying on the ground of the sea. It is also an important problem to get their total length and initial strain. Considering of the criterion, I deduce the formula of the minimal total length of the mooring chains on the basis of the theory of catenaries and programmed relative programs to determine total length of the mooring chains and their initial strain. I heartily wish that my job in this paper could provide some useful reference for the practical engineering.