Research On The Influence Of Draft Survey Accuracy Caused By The Vertical Component Force Of The Anchor Chain

In order to better analyze the errors and reduction methods in the process of draft survey,based on the analysis of domestic and foreign scholars' analysis of draft survey errors of bulk carriers,based on the error propagation principle,the draft survey errors were analyzed.On the basis of summarizing the relevant theory of error and the method of draft survey,the transmission law of error in the process of draft survey is analyzed.Through reading a lot of literature to sort out the systematic errors existing in the draft survey process,among the numerous errors,the systematic errors caused by the vertical force component of the anchor chain and the cable have not been effectively corrected.Based on the' "Port Engineering Load Code" and existing' research results,through the analysis of the horizontal and vertical component of the ship's wind pressure and water flow,the horizontal external force(that is,the horizontal force of the anchor chain tension)is obtained.Reaction force),combined with the mechanics principle and the ship's mooring state,the calculation model of the vertical force of the anchor chain tension is established.This model can be used to solve the correction of the system error caused by the vertical force of the anchor chain.The calculation example shows that when the wind speed is 13m/s and the flow velocity reaches 4kn,this error alone has reached 28%of the allowable error of the draft survey.The vertical force component calculation model of the anchor chain based on the ship's wind and flow load has the disadvantage of tedious calculation process,and manual calculation is easily affected by human factors,which can easily cause calculation errors and make the final measurement results inaccurate.In response to this problem,a visual human-computer interaction interface was first designed using the PyQt5 module,and then an anchor chain with interface visualization,'data storage and extraction,exception reminder and calculation functions was developed by using the Python language OS library,traceback library and defined functions Automatic calculation software for vertical component force.Using the data to test the software,the results show that the software can quickly and accurately calculate the vertical force component of the anchor chain on the ship,and use the software to calculate the vertical force component of the anchor chain in the water gauge measurement work,Can improve work efficiency and water gauge weight accuracy,and has a wide range of applications.In summary,this research can further improve the weight measurement algorithm of the bulk carrier water gauge,which can be used for reference by relevant practitioners.