Redesigning Generator of Landing Craft Tank 1500 DWT by Considering Technical and Economic Factors

The electrical system is very important thing on a ship, where the tool that functions as power to meet the electricity needs on the ship is a generator. In some cases, generator planning does not pay attention to technical and economic factors that have an impact on operations cost. The technical factor will be adjusted to the standard and regulations of the classification board, while the economic factor will be planning an efficient electrical installation and power installation system. The results obtained from this paper show the operational needs of the ship based on the condition when harbour, sailing, loading and unloading, and emergency during the day with total intermittent load of 110,6 KW and total continuous load of 130,6 KW while the operational needs of the ship at night with total intermittent load is 98,2 KW and total continuous load is 181,5 KW. Then it was found that the largest operational power requirement of the ship in an emergency at night was 38,5 KW and the largest power was in the condition of the ship at night of 102,5 KW. Then we get 3 generators with 2 sets of 60 KW power capacity and 1 set of 45 KW.


Introduction
The electrical system on the ship is an important thing in designing a ship. Generator is one of the equipment on the ship that is useful to meet all the power needs on the ship. In determining the capacity of the generator that will be used to meet the power needs of the ship, a load calculation will be carried out to determine the power capacity and changes in use for each operating condition. The goal is to find the minimum and maximum power required [1]. In some cases, Landing Craft Tank (LCT) 1500 DWT ship at Dok dan Perkapalan Kodja Bahari Jakarta Shipyard Unit III has a very large generator power so that it becomes inefficient for planning generator power requirements. Therefore, this paper aims to redesigning generator of LCT 1500 DWT by considering technical and economic factors. The technical factor in question is in accordance with the regulations that have been issued by a class, which in this case is the Indonesian Classification Bureau (BKI). Meanwhile, the economic factor in question is the efficiency of calculations regarding the determination of power installations and lighting installations. The author will calculate the load factor and the diversity factor on the ship. The load factor will be calculated conditions when harbour, sailing, loading and unloading and emergency. To calculate the

Windlass and anchor motor power
Included in the Indonesian Classification Bureau (BKI) volume 2 of 2018, regarding the calculation of the anchor plan, the following formula can be used to calculate the anchor plan: = + 2. ℎ. + (1) where

Winch and Lifeboat Electric Motor Power
According to the book "Ship Equipment and Supplies" written by Sukarsono N.A. On page 75, the motor power of the lifeboat can use the following formula: = ; ( ) (2) where W = weight of lifeboat + weight of equipment + weight of crew [kg] According to the book "ship systems and equipment" by Sukarno NA, the lifeboat and equipment weighs 2,960 kg, H = lifeboat height [m], = motor efficiency, i.e. 0, 98 (for new motorcycle)

Winch and Ramp Door Motor Power
According to the book "Merchant Ship Design Hand Book Volume 5" page 58, calculating the winch drum can use the formula: .
. . ( . ) ; ( ) (3) where k = provisions for wire rope 1,2, d = Steel rope 3/4 inch [m], L = Length of rolled steel rope, n = standard roll rope maximum 7, D = Diameter of drum Then perform Hydraulic calculations based on "Maker Bosch Rexroth Hydraulics, Theory and Applications" using the formula: = ; ( ) (4) where F = Load on winch drum 9810 N, r = radius of winch drum [m] Then calculate the flow rate of the electric motor using the formula: = .
; ( min ) ⁄ (5) Then the calculation of the power input from the electric motor will be obtained using the formula: = .
. % ; ( ) (6) where Q = Flow rate pump [lt/min], p = 207 bar (existing), t = v x hm = 0.85 x 0.98 = 0.765 The last step is to calculate the power output of the electric motor using the formula: = . . % ; ( ) (7) where Q = Flow rate motor [lt/min], p = 207 bar (existing), t = v x hm = 0.85 x 0.98 = 0.765 From the calculation above, the power from the electric motor will be obtained according to the winch.

Air Conditioner (AC)
According to the book "Ship Equipment and Supplies" written by Sukarsono N.A. On page 75, the AC motor power can use the following formula: ; ( ) (8) where V = Room volume [m3]

Lighting Equipment
Determination of lighting equipment on the ship in accordance with the book "Merchant Ship Design Hand Book Volume 5" is divided into 3 parts of lighting. First, inside Lighting (a), includes interior lighting covers rooms such as rooms on the main deck, poop deck, and wheel house deck. Second, external lighting (b), includes aisles on the outside of the ship, as well as places for lowering lifeboats. Third, navigation lighting (c), includes lights used by ships when sailing, loading and unloading or leaning, and so on. So from the three parts of the lighting, the total lighting on the ship can be calculated with the following formula: = + +

Other Electrical Equipment
The electrical equipment in question is equipment that can support the completeness of the ship, such as equipment in the kitchen (a), washing equipment (b) and navigation and communication equipment (c), the following formula is:

Generator Power Capacity Calculation
In this case it will be explained about the calculations in analyzing the power capacity of the generator, as follows:

Load Factor
The load factor is very important when planning the generator capacity to distribute all the electrical power requirements on the ship. The load factor is defined as the ratio of the working time of the equipment under certain conditions to the total working time under these conditions [3].

Continuous Load (CL)
Equipment that operates continuously under normal operating conditions. Here is the equation formula = ; ( )

Diversity Factor
In short, the diversity factor is the operating load in determining the total load on the generator. Where the value of the diversity factor according to the Indonesian Classification Bureau (BKI) should not be below 0.5. So the author uses a reference from the energy and electricity journal STT-PLN Vol.9 No.6 regarding "Electrical System on the Frosch-class Navy Warship KRI Teluk Celukan Bawang 532" which uses 0.6 for the diversity factor value. The following is the equation formula for calculating the diversity factor, as follows: where e = Diversity Factor [kw], IL = Intermittern Load [kw]

Power Requirement
The following is the formula for calculating the electric power capacity (power requirement), as follows:

Total Load Power Calculation
The following is the formula for calculating the total load power, as follows: 4 Analysis

Main Properties
Main properties is obtained from secondary data collection from Dok dan Perkapalan Kodja Bahari Shipyard Unit III. This data will be used as a reference for generator calculations, it can be seen in table 1, as follows:

Winch and Electric Motor Power Ramp Door
To calculate the winch and electric motor power, a list of materials used in the ramp door is required, the material list is obtained from secondary data collection, below is a list of materials that can be seen in table 3, as follows: ; ( min ) ⁄ = .
. ; ( min ) ⁄ = 26.1 ⁄ Then the calculation of the power input from the electric motor will be obtained using the formula:

Air Conditioner (AC)
In calculating the electric motor power for the Air Conditioner (AC) it takes room volume data from the general arrangement of the LCT 1500 DWT ship which is obtained from secondary data collection. In this case, the measurement of the volume of the room contained on the main deck will be carried out, as follows:  In this case, a measurement of the volume of the room contained in the wheel house deck as follows:

Pumps
The data on the power requirements of the pumps are obtained from secondary data collection, as follows: Table 7. Pump power requirement

Calculation of Lights on The Ship
The planning of lighting on the ship is based on the book "Merchant Ship Handbook Vol 5", as follows:

Other Electrical Equipment Calculation
The following are the power requirements of other installed electrical equipment, based on the book "Merchant Ship Handbook Vol 6", namely: In this case, the power used in kitchen equipment will be determined, as follows: In this case, the power used in washing equipment will be determined which can be seen in table 15, as follows:

Analysis of Generator Power Capacity Calculation during Day Night
At this stage, calculations will be made during day night conditions, as follows: it can be seen that the operational power requirement of the ship at night with a total intermittent load of 98,2 KW and a total continuous load of 181,5 KW and power requirements in an emergency vessel condition of 38,5 KW and the largest power is in the condition of the sailing vessel of 102,5 KW

Generator Selection
The generator selection is based on the calculation of the largest operational power capacity which is located on the condition of the ship sailing at night as much as 2 sets. Then we get a generator with the following capacity:

Conclusion
In accordance with the calculation results obtained with various ship operating conditions. The condition of the ship anchored during the day is 49.8 KW. The condition of the ship anchored at night is 64 KW, The condition of the ship sailing during the day is 100.3 KW, The condition of the ship sailing at night is 102.5 KW. The condition of loading and unloading ships during the day is 58.2 KW. The condition of loading and unloading ships at night is 74.6 KW. Emergency ship condition during the day is 32.9 KW. The condition of the emergency ship at night is 38.5 KW. Determination of generator power capacity based on the operational electricity needs of the largest ship when the ship is sailing as many as 2 sets with power 60 KW x 2. Then determine the generator power capacity based on the condition of the ship when in an emergency as much as 1 set with power 45 KW x 1.