The Calculation Of The Connecting Forces For The Connecting Device Of The Sea Mules

The development of sea mule has been a rather long history. Practice has proved that it is an advanced form of transport. However, the design of sea mule is a very complex technology. There must be a coupling device between tug and barge, which has good sea keeping ability;however, one of the main basis of the design of the device is the determine of the connecting force.This article calculates the connecting forces of bug and barge and conducts preliminary exploration based on Strip Theory.The article uses strip theory to calculate added mass ,damping coefficients, wave forces of bug and barge at different stages (different speeds, different wave angles) preparing for the calculation of the connecting forces (including change monomer ship calculation procedures to Tail ship's);Then take the bug and barge as a whole, amend the angles of wave forces, consider the mutual conditions of the movement and the power of the connecting device, establish coupling equation and coupling matrix of two ships;At last according to the final matrix computation, Gauss method is used to resolve the matrix to get the connecting forces.The article chooses a sea mule as the calculation model to calculate the connecting forces at different speeds, different waves angles, different wave heights, through the comparation of theoretical datas and experimental ones, the method can be used in works and is feasible to forecast the preliminary connecting forces.Currently, the research of connecting forces are mainly based on experiments. Because tests are extremely expensive and skills are difficult, the determine of the connecting forces sometimes are roughly estimated based on the percentage of the tub's displacement. The paper uses a simple mathematical model to calculate the connecting forces and gives out an estimate formula. As the basis of the design of the connecting device, the formula the paper gives out has its actual value.The paper is supported by the project of the key technical studies of the dry bulk cargo transport of tub-bug systems. Project number is: 2003EG124133.