Technical program of the replacement of CPP for 鈥淴iangyanghong 06鈥漇cientific Research Vessel passed the verification of expert Group

The investigation meeting regarding the technical program of CPP replacement for 鈥淴iangyanghong 06鈥� scientific research vessel was held in Nanjing, dated from August 28 to 29, 2012. The meeting was presided by Yan Zeding, the vice chief engineer of CSSC Chengxi Shipyard Co., Ltd, attending with the engineers from North China Sea Branch of State Oceanic Administration, Shanghai Jiahao Ship Designing Co., Ltd, CCS Nanjing, CCS Chengxi Shipyard and Nanjing High Accurate Marine Equipment Co., Ltd.

As the CPP supplier of this project, Chen Yongdao, the general manager of Nanjing High Accurate Marine Equipment Co., Ltd.(NGC Marine Company) made a simple introduction of the company and expressed NGC people鈥檚 determination and confidence to complete this project. Xu Xiansheng the vice director of North China Sea Branch of State Oceanic Administration introduced the operation condition of the ship, and NGC marine technical department made a report to the experts in the aspects of system designing, components selection, structural designing, FEA calculation, alignment and vibration calculation, hydraulic remote control system and approval suggestion of Society, etc.

This is a renovation to an old ship that is to transform the box-type cargo ship to scientific research ship. The research ship need to do the observation at the low speed: 0-6 knots, and the original fixed pitch propeller can not satisfy this requirement; therefore, the ship owner requested to change the FPP to CPP to satisfy the operation condition. Based on the original arrangement, the CPP would be driven by 4-cylinder low speed engine, and the shaft span is very short, and there is no gearbox and flexible coupling, therefore, the torsional vibration stress of the system is very big, which brings lots of trouble to the new designing. One domestic CPP supplier tried to do this job in 2011, however, it failed because the torsional vibration stress can not meet the requirement of Classification Society.

To finish the job, NGC marine engineers had done lots of preparation. First, to change the structure of oil distribution shaft to improve the allowed stress; second, to apply the latest international designing philosophy into the shaft arrangement to optimize the designing, and together with the application of 5-blade propeller and large pressure middle bearing seat, the shaft vibration problem produced by 4-cylinder low speed engine was removed. To get a reliable program, NGC invited DNV for technical support. Via calculation, DNV considered that the designing program of NGC Marine Company is free of vibration problem, only to set a barred-speed range within the relative speed range. In addition, to guarantee the program is free of risk, according to CCS鈥檚 requirement, NGC Marine Company also invited the experts from MAN to do the calculation and assessment to the torsional vibration stress of crank shaft, and this expert confirmed completely that the torsional stress is totally in conformity with MAN Standard. At present, the drawings and calculation had been approved by CCS.

 
Meeting site

After the detailed report of NGC engineers, the experts group made a complete communication and discussion with NGC designing team regarding some technical points, and they gave high comments to the efforts and achievement NGC Marine Team had made. Based on the verification of DNV and MAN experts, and the approved drawing and calculation from CCS, they thought the program was qualified to the production.

In the meeting, Shu Yongdao, vice general manager of NGC Marine Company gave his thanks to the great support of every party. Even the project was of big difficulties, and was the first try in China, NGC had made initial achievement in designing, and in the production period, NGC would control the quality and schedule strictly to ensure that the product can meet the requirement during the operation.

In the end, Yan Zeding and representatives of ship owner gave high appreciation to NGC鈥檚 efforts, and put forward further requirement to the later job.

  
Experts in NGC Marine Company鈥檚 work shop