ENGINE PROPELLER MATCHING ANALYSIS ON FISHING VESSEL USING INBOARD ENGINE

Fishing vessels which are used for one day operations usually use outboard engines as their driving motor. However, to improve the performance of propulsion systems, and consequently the performance of ships, inboard engines are now being used. In this study, the propulsion system of a ship was modified by upgrading from an outboard to an inboard motor. Meanwhile, the study aims to obtain an optimal interaction between the propulsion system and the hull shape of the ship. It was conducted by calculating the ship’s resistance using the van Oortmerssen method, and validating the result using the CFD method. Furthermore, thrust and torque calculations were performed to obtain the characteristics of the ship’s propellers, and the results were validated using the CFD method. The result obtained from the calculation of the ship’s resistance was a New Fishing Vessel engine power of 11 HP. 4 types of B-Series propellers characterized based on the size of their pitch, including 14.00 inch, 14.25 inch, 14.50 inch, and 14.75 inch were, analyzed using the engine propeller matching analysis. The results show that the propeller with the pitch size of 14.75 inches was the best, as it had a power of 100%, speed of 25.35%, and efficiency of 32%. Therefore, it was chosen as the new propeller for New Fishing Vessels.


INTRODUCTION
A Fishing vessel is one of the common means of transportation used by fishermen to find fish in the sea. Fishermen are one of the main sources of income, especially on the north coast. This shows that fishing boats must have maximum performance in line with the fish catch and operational costs of the fishermen [1]. In theory, the ship gets a restraining force called resistance. This resistance must be countered by the thrust generated by the ship's propulsion system. The ship must have a propulsion system following the shape of the hull of the ship can result in optimal interaction between them, so that the performance of the ship's propulsion system is optimal [2]. Based on the results of field studies, the majority of the propulsion systems on fishing vessel use an outboard engine. In its development, some of the propulsion systems for fishing vessel with one-day fishing operations have used an inboard vessel because it is considered more efficient than using an outboard engine. In this case, fishing vessel usually only use a single propeller, but the size of the propeller varies so that each fishing vessel has a different performance [3]. This can be influenced by the size of the propeller pitch. In the research of the MT.NUSANTARA's ship due to changes in the propulsion system, engine propeller matching was carried out to find the match between power and speed of the main engine and propeller. From the research, it was found that the main engine and propeller had the best match point [4]. Besides, in engine propeller matching research by changing the shape of the hull of the ship, resulting in a new main engine and propeller which is considered to be able to optimize the performance of the drive system [5]. From some of the studies described above, the author wants to do further research on engine propeller matching by changing the shape of the hull, which initially uses an outboard engine to be converted into an inboard engine. This study aims to obtain the optimal propulsion system on the New Fishing Vessel using an inboard engine. The benefit of the research carried out is as a reference in providing information related to the effect of changing the fishing boat drive system with an outboard engine to an inboard engine for those in need. This research also has the following objectives: : 12 knots Besides, the data lines plan from the old fishing vessel is also obtained in Figure 1:  : 6 knots Besides, the data lines plan from the new fishing vessel is also obtained in Figure 2:  : Right-Handed The author researched to obtain resistance, thrust, and torque values using the Computational Fluid Dynamics (CFD) method in the fisheries laboratory and small ships located in Building B, Joint Lecture Building, Department of Naval Architecture, Diponegoro University. The data obtained from data processing is then analyzed to obtain the desired results. The methods used in this research include :

Model Making and Analysis
In determining the amount of ship resistance the ship is modeled from the data lines plan using Computational Fluid Dynamics (CFD) software which is then validated using the van Oortmersen method calculation. The calculation of resistance in this study was carried out using the Maxsurf Resistance software which was then validated with the resistance value obtained from the calculation of the CFD software Ansys Workbench 18.1. For the manufacture of a shipping pool in the CFD software can be seen in Figure 3. The size of the shipping pool is 1L for the front of the ship, 3L for the back of the ship, 2L for the right side of the ship, 2L for the left side of the ship, and 1L for the bottom of the ship, with the boundary conditions used in the simulation, namely : Inlet, Outlet, Outflow, Sidewall, and Wall as shown in Figure 2 [7]. Meanwhile, to determine the thrust and torque values, propeller modeling was carried out using Computational Fluid Dynamics (CFD) software which was then validated by manual calculations. Then to make a propeller pool in CFD software can be seen in Figure 4. For the size of the propeller pool in the CFD software, which is 2 diameters (D) for the rear of the propeller, 5D for the front of the propeller, and 3D for the

Matching Points are defined
Matching point is a point where the value of the main engine rotation (engine speed) is exactly the same (match) with the propeller character, which is the operating point of the motor rotation where the power absorbed by the propeller is the same as the power produced by the main engine, so that it can produce service speed the ship is exactly the same (approaching) at the planned speed [6]. The propeller characteristics are as shown to be able to equalize the two trendlines into the same plotting means, so that first the prices of the two trendlines are expressed in percent (%) as shown in Figure 5.  At the main engine rotation, n, which is following the propeller load conditions, because the power generated by the main engine is the same as the power absorbed by the propeller, P. So this will have an optimal impact on the fuel requirements of the ship's main engine on speed. service of the ship that has been planned [6].

Ship 3D Modeling
To be able to analyze ship resistance required a 3D model of the ship. The old fishing vessel modeling was made based on the lines plan in Figure 1

Calculation of Ship Resistance
In calculating the value of ship resistance, the author uses the Van Oortmerssen method and then validates the accuracy of the resistance value using the Computational Fluid Dynamics (CFD) method. On the old fishing vessel has a service speed of 12 knots and the new fishing vessel has a service speed of 6 knots, the calculation of resistance using the Van Oortmerssen method is done with software.

Resistance Validation
Validation is carried out to determine the accuracy of a method used, by comparing the results between the two. Calculation of resistance with the CFD method using software, ship modeling, and meshing must be done as well as possible so as to avoid errors that may occur in calculations. After calculating the resistance using the CFD method, the results of resistance are obtained as in table 2. The value of the barrier validation correction meets the requirements, which is below 5% [8]. This shows that the two methods used are valid. Then the calculation of the required engine power on the new fishing vessel will be carried out.

Calculation of Ship Engine Power
Because of the Ship new fishing vessel uses an inboard engine, then the calculation of the engine power of the ship is carried out as follows [9] :

Propeller Selection
After knowing the propeller characteristics, the thrust propeller value is calculated as follows [10] : In developing the propeller characteristic 'trend', the variables involved are propeller speed and propeller torque, which are then developed into the following equation [6] : Qprop = Kq x ρ xx n 2 D 5 (10) = 0.0214 x 1025 xx 13,33 2 0,381 5 Qprop = 49,897 After that, calculations are carried out using the CFD method to get the thrust and torque values as follows.  The results of the calculation of thrust and torque using the B-Series diagram with a propeller pitch of 14.00 inches have been validated using the CFD method with correction of 0.0085 for thrust calculations, and 0.00175 for torque calculations, so that the CFD setup is said to be valid and usable. to calculate the propeller with other variations in the size of the propeller pitch. Then the results of the calculation of thrust and torque propeller are obtained as shown in Tables 4 and 5.

Engine Propeller Matching
Then the propeller power (P) calculation is performed so that the engine propeller matching analysis can be carried out for each propeller using the equation formula 11 [6]. Pprop = Qprop x Speed Propeller (11) From the calculation of the power of variation in the size of the propeller pitch, the results are as in table 7. From the calculation, the propeller power is obtained with the propeller pitch of 14.75 inches, namely the power 11,2184 HP. Then the calculation of the power and speed of the main engine and also the variation of the propeller is done by changing it in percent (%) so that the engine propeller matching analysis can be performed as shown in Figure 9.

Identification Old Propeller Characteristics
In developing the propeller characteristic 'trend', the variables involved are propeller speed and propeller torque, which are then developed into an equation like the following : It is known that the thrust value for old fishing vessel is as follows : Next is to perform calculations using the CFD method to find out the thrust and torque values. Then the calculation validation is carried out as shown in table 8 and  table 9.  Then the propeller power (P) calculation is carried out so that the engine propeller matching analysis can be carried out for the old propeller [6]. Pprop = Qprop x Speed Propeller = (8,4746 / 1000) 5500/60 x 2 x 3.14 Prpop = 6,54375 HP From the results of the old propeller power calculation, the propeller power is 6.54375 HP. Then calculate the power and speed of the main engine and propeller by changing it in percent (%) so that the engine propeller matching analysis can be performed as shown in Figure  11. Based on Figure 11, it can be seen that the engine and propeller characters do not have a match point because the engine power is not absorbed effectively by the propeller.

Comparison of the Engine Propeller Matching of Old Fishing Vessels and New Fishing Vessels
Engine propeller matching analysis has been carried out for old fishing vessels and new fishing vessels. The comparison of the propeller characteristics used by the two ships and the difference in match points is shown in  The comparison of the engine propeller matching chart between old fishing vessel and new fishing vessels can be shown in Figure 12: Based on the results of the matching point comparison shown in Figure 12, new fishing vessel with inboard engine is better than old fishing vessel with outboard engine. Old fishing vessel own matching point between the character of the engine and the character of the propeller ranges from 100% rated power and 15.64% rated speed. Meanwhile, new fishing vessel has matching point between the character of the engine and the character of the propeller ranges from 100% rated power and 25.35% rated speed. So that the operating point of the motor rotation is where the power is absorbed by the propeller equal to the power produced by the engine and the resulting ship speed close to (exactly) the planned ship service speed.

CONCLUSION
Based on the comparative analysis of engine propeller matching between old fishing vessels and new fishing vessels, it can be concluded that new fishing vessel with inboard engine Having a resistance of 855,614 N is the best new hull form, then calculating the main engine obtained by the main engine with a power of 11 HP to be able to overcome the drag of the ship, After that, the engine propeller matching is carried out on a B-Series propeller with a different propeller pitch size. Obtained the best match point value on the propeller with the pitch propeller size, namely 100% rated power and 25.35% rated speed with propeller efficiency of 32%. so that a propeller with a 14.75 inches pitch propeller was chosen as the propeller used for new fishing vessels.