Propulsion System Design for Coastal Minehunter Vessels

INTRODUCTION

[CE 1.1]I completed this project during my bachelor degree in the field of Naval Architecture and Marine Engineering. The title of the project was “Propulsion System Design for Coastal Minehunter Vessels”.

BACKGROUND

[CE 1.2]A crucial system in the propulsion system in every ship which is particularly responsible for the movement in the vessel. It must determine vessel total resistance as it was considered the most important issue. Designers can design appropriate propellers based on the resistance results along with the propeller shafts, main engines capacity and auxiliary equipment associated with the ownerships’ needs. It also assist the designers to predict the estimated cost for the whole propulsion system and the designed ship overall arrangement.

[CE 1.3]The main project objective was related to the determination and preliminary system designing of the propulsion system which was related to the coastal Minehunter vessel and it was required to operate in Australian waters. I did necessary calculations for determining the designed vessel resistance which was based on the Holtrop-Mennen resistance estimation method. Moreover, I evaluated the prime movers general parameters, shafts and propellers which indicated the total vessel resistance outcome. I even conducted the quick survey related to the similar ships propulsion system for obtaining the brief comparison. Moreover, it was also needed to obtain the preliminary drawings of the selected propulsion system and whole system auxiliary equipment. But there were few parameters which were assumed for the purpose of assuring the smooth calculation process. I utilized and implemented the Lloyd’s classification register.

[CE 1.4]The overall project nature was based on the implementation of the propulsion system design which was related to the coastal Minehunter Vessels. I divided the project into several milestones which were followed throughout the project for the successful project execution.

[CE 1.5] My position is shown in the below organizational chart -

[CE 1.6] Following were my major project related responsibilities:

• I obtained the resistance which was formed for the vessel moved out at any velocity.
• I overcame the total resistance with the vessel’s thrust and it was needed for the movement of ship.
• I implemented the Holtrop formula for the purpose of calculating the total vessel force resistance.
• I conducted only the preliminary design calculations associated with the resistance and I ignored some minor resistance.
• I obtained the propeller blades total number which was followed with the blade area ratio.
• I then obtained the open water diagram which was based on the B-Series Propellers for 5 blades and set the value of Ao as 0.5’.
• I determined the water propeller open efficiency from the chart along with the thrust coefficient and the coefficient of torque.
• I then determined the optimum propeller speed for the diameter limitation of the propeller which was selected to be 1.8m.
• I ensured the proper system operation in this step which was based on the propeller shaft system and it was smooth enough to avoid necessary problems associated with the propulsion system.
• In this project, I also illustrated the lubrication system for the propeller shafts which further included the major components.
• I obtained the total speed of 340 rpm which was the overall propeller speed and the main engine output speed was 2600 rpm.
• Thus, for ensuring the engine speed transfer to the propeller, I selected the shaft system for equipping the gearbox. It resulted in decelerating the main engine towards the propellers speed with proper handling.
• I also calculated the reduction ratio which was the main parameter of the gearboxes.

C) Personal Engineering Activity

[CE 1.7]I took subjects related to the propulsion design while pursuing my bachelor degree in Naval and Marine Engineering. It built my confidence to successfully implement the project objectives associated with it. Moreover, I even got the chance to attend various sessions related to the Marine Engineering which also built my strength in this regard. Furthermore, there were various technical published papers related to the designing of the coastal Minehunter vessels which assisted me well in the execution of my design activities. At various stages, I got stuck into technical problem and my supervisor advised me well for successfully figuring out the problem and obtaining the desired project results.

[CE 1.8]I obtained the resistance which was formed for the vessel moved out at any velocity. Hull’s vessel was used for creating it with providing the physical environment which include air and water. I overcame the total resistance with the vessel’s thrust and it was needed for the movement of ship. I implemented the Holtrop formula for the purpose of calculating the total vessel force resistance.

I conducted only the preliminary design calculations associated with the resistance and I ignored some minor resistance and thus, the formula for total resistance is shown below.

[CE 1.9]I obtained the propeller blades total number which was followed with the blade area ratio. I then obtained the open water diagram which was based on the B-Series Propellers for 5 blades and set the value of Ao as 0.5’. I determined the water propeller open efficiency from the chart along with the thrust coefficient and the coefficient of torque. I drew the ship demand which was done with the help of the chart.

I used the Kt ship curve along with the open water diagram and obtained the following values.

• Coefficient of thrust, KT = 0.157
• Coefficient of torque, KQ = 0.075
• Propeller efficiency in open wate, ηO = 0.81
• Value of optimum advance coefficient, Jopt = 0.88

I then determined the optimum propeller speed for the diameter limitation of the propeller which was selected to be 1.8m.

[CE 1.10] I ensured the proper system operation in this step which was based on the propeller shaft system and it was smooth enough to avoid necessary problems associated with the propulsion system. In this project, I also illustrated the lubrication system for the propeller shafts which further included the major components and these components are shown below.

[CE 1.11] I obtained the total speed of 340 rpm which was the overall propeller speed and the main engine output speed was 2600 rpm. Thus, for ensuring the engine speed transfer to the propeller, the shaft system was selected for equipping the gearbox. It resulted in decelerating the main engine towards the propellers speed with proper handling. I also calculated the reduction ratio which was the main parameter of the gearboxes. I calculated it by utilizing the below mentioned formula and obtained the value of 7.647.

D) Summary

[CE 1.12] I obtained the input data from the clients and did the calculations by adopting the suitable method which overall suited the vessel design. I completed all the preliminary calculations related to the propulsion system and it included the basic parametric calculations related to the overall system design. The best and optimum propulsion system was selected based on the weight, size, needed cost and space. Therefore, in this project, I successfully calculated the propulsion system preliminary design which was related to the vessel for Australian Navy. The table below shows the design parameters and obtained values.

Overall, this project made me learn concepts related to the Marine Engineering at the completion of this project. Overall, this project made me learn concepts related to the Marine Engineering at the completion of this project.

To read complete CDR.............. Kindly check the below links.