Analysis of Workload on Fibre Ship Development Project Using Workload Analysis and NASA-TASK LOAD INDEX Methods

One of the fibre shipyards in Surabaya has 16 workers who play a direct role in shipbuilding activities. Every year this shipyard experiences an increase in the number of job requests. The more demand for shipbuilding, the workers involved also have to work harder. The purpose of this study is to find out how the workload is owned by the workforce and determine the optimal number of workers so that it can be used as a reference for decision making in the construction of the next ship. This research will use Workload Analysis and NASA-TLX methods. The results of the analysis using the Workload Analysis method resulted in a recommended workforce of 21 people so that 5 additional workers were needed. While the results of the analysis using the NASA-TLX method, the recommended workforce is 28 people, so there needs to be 12 additional workers. With this addition there is no excessive workload owned by the workforce.


Introduction
The industrial world that is increasingly advanced and developing as it is today requires business actors both in the service and manufacturing sectors to be more competitive in competing.This competition cannot be separated from the role of a good management system so as not to lose to competitors' competition.Therefore, human resources are one of the most important aspects in business activities.
Every activity usually begins with planning or planning.Therefore, human resource planning is also a must in the company's operations.In human resource planning, one of them is the number of workers.To determine the number of workers the company must also adjust to the workload that will be received by the existing workforce.Workload is the effort that must be expended to meet the overall demand for tasks given to the workforce, a measure of the limited ability to do certain work.In the perspective of ergonomics, the workload obtained by the human body must be appropriate or balanced on the ability or physical capacity, cognitive abilities and limitations of the human body that receives the load.The working ability of the human body differs from one individual to another, because it is very dependent on the level of skill, physical fitness, nutritional status, gender, age, and size of the human body [1].The workforce has a very important role for the success or failure of a company.Apart from the workforce, shipyards can also be harmed because they have to bear the consequences of an excessive workload on their workforce.One of these risks is the risk of work delays due to decreased labor productivity.Due to the delay, the company had to pay a fine per day of 1/1000 of the applicable contract value and in this study, it was Rp.2,368,770.00 per day.Companies can also lose customer trust, up to a tarnished reputation due to untimely completion of work.Another loss that can occur is causing the shipyard to pay more for the costs of overtime workers.The alternative solution that can be done is by optimizing the number of workers in each department through calculating the workload on the workforce.
In this study, we will calculate the workload of the workforce involved in the construction project of a passenger ship with a capacity of 25 people.The method used in this research is NASA-TLX and Workload Analysis.The National Aeronautics and Space Administration Task Load Index (NASA-TLX) was chosen because it is considered to have indicators that represent the mental workload of the workforce.According to Casner and Gore, the NASA-TLX measurement technique has been developed to mitigate problems that arise due to differences in human thinking about workloads [2].Workload Analysis method is used to calculate the workload objectively and is expected to provide an alternative number of workers.According to Anggraini in Farhana (2020) using the Workload Analysis method will provide information regarding the allocation of human resources to complete the existing workload [3].

Methodology 2.1 NASA-TLX
The National Aeronautics and Space Administration Task Load Index (NASA-TLX) is a multidimensional scale designed to obtain workload estimates from one or more operators while they are performing a task or shortly thereafter [4].The NASA-TLX measurement technique was developed to reduce problems that arise from differences in thinking about workloads [2].NASA TLX asked respondents to subjectively rate their workload using a single scale.Respondents will rank them on six workload subscales as in the table 2 Assessment with NASA-TLX can be done by performing the following four steps: 1. Weighting In the weighting procedure, respondents will be given a questionnaire in the form of a comparison consisting of 15 pairs from the NASA-TLX sub-scale [5].Respondents were asked to choose one of two subscales that they felt were more burdensome for the participants in carrying out their duties.After that the tally calculation will be carried out.

Rating
After the weighting will be given a rating, the measurement of the rating (rating) is calculated from a questionnaire with 6 sub-scales of mental workload dimensions with a value range of 0-100 (lowhigh).f.Determination of the optimal number of employees for each position is obtained by rounding up from the results of calculating the amount of workload.g.Comparing the number of initial employees and the number of recommended employees

Working Time Measurement
The measurement of working time is a method of applying a balance between the human activities that are contributed to the unit of output produced.To calculate the standard time (standard time) for the completion of work in order to choose the best alternative work method, it is necessary to apply the principles and techniques of work measurement (work measurement or time study).Standard time is the time required by a worker who has an average level of ability to complete a job.Thus, the standard time generated in this work measurement activity can be used as a tool to make a work scheduling plan that states how long the activity must last and how much output is produced as well as the number of workers to complete the work.
According to Wignjosoebroto (2006), in general, the techniques for measuring working time are divided into two [7], namely: 1. Direct measurement of working time Measurements are made at the place where the work being measured is taking place.

Indirect measurement of working time
Measurements are made without the observer having to be at the place where the work being measured is in progress.
Methods of measuring working time, either directly or indirectly, are grouped as follows: Make several observations with the intention of determining the estimated p value.Determination of the required number of observation samples can be found by the following formula:

4)
Where: Sp = desired level of accuracy in decimal p = Percentage of observed activities N' = Number of observations made k = Index price depends on the level of confidence For a 68% confidence level the value of k is 1 For a 95% confidence level the value of k is 2 For a 99% confidence level the value of k is 3 6.Develop an observation plan.
The results of the initial observations are used to calculate the frequency of observations.7. Carry out actual observations

Results and Discussion
This research was conducted on a new passenger ship construction project.This ship is a type of fiber ship with a capacity of 25 people.This passenger ship is equipped with two 200HP outboard engines to propel the ship.In addition, this ship has other specifications as follows: Length

Pre-work Sampling
After knowing the work elements of each section, the next step is to carry out the initial observation stage or Pre-Work Sampling.This stage makes observations on each worker with a random time of 30 observations in 1 day so that the initial incidence ratio is obtained.The initial ratio of this observation is in the form of a productive percentage which will be used as an estimate of the actual number of observations at the Work Sampling stage that will be carried out.The results of the percentage of productive owned by each workforce can be seen in table 3 From the productivity results in table 4.3, it can be calculated the estimated number of observations at the Work Sampling stage that should be carried out to minimize the possibility of insufficient data.Calculation using the formula 2.4, for example the number of observations that must be made on the Admintek workforce is 148 observations.Where the level of confidence (k) used is 95% or equal to 2. While the level of accuracy (S) used is 10% or equal to 0.1.

Work Sampling
At the work sampling stage, the procedure carried out is observing work activities at random intervals of one or more objects and noting on the observation worksheet whether the object is working or idle.Thus the results will be obtained in the form of the percentage of working and not working.For example, the productive percentage owned by Admintek is 81.44%,Warehoouser 1 is 75.08%, and Warehouser 2 is 78.5%.Recommendations are made based on the total workload of each section.For example, Welder has a combined workload of 400% with 3 workers.The results of the recommendations indicate that it is necessary to have an additional 1 person so that the average workload becomes 100%, so that the workload is classified as normal.However, the logistics workforce has a combined workload of 196% with 2 workers.The results of the recommendations show the need for a workforce of 2 workers, so there is no need for an additional number of workers.

NASA-TLX
To reduce the mental workload, the proposed improvement is by adding more workers by dividing the total mental workload by the number of workers.From the results of the division, the average workload will be obtained.The addition of workers aims to reduce the average mental workload of workers.Table 4.14 shows the calculation of manpower recommendations using the NASA Task Load Index method.Table 3.7 shows the results of the recommendations using the NASA Task Load Index method.In these results obtained the number of recommended workforce as many as 28 people, so it is necessary to add 12 people.With the addition of 12 workers, there will be a change in the mental workload assessment which was originally heavy and very heavy to moderate.Table 3.8 shows the details of the addition of workers.

Table 2 . 2
Pairwise Comparison of Indicators

Table 2 .3 Rating Indicators
Sumber: Simanjutak, 20103.Weighted Workload (WWL) CalculationCalculating the workload score, the first step is to calculate the weighted workload (WWL), to find out the WWL value is done using the formula 2.1: = Σ ( × ) ...(2.1)Then in the second step the WWL score is divided by the total weight of 15, as calculated Workload can be obtained from: a. Knowing the organizational structure and job description of each position.b. Determine the completion time of activities for each position.c. Make observations to calculate the percentage of productive and non-productive.
In the project work on the construction of a passenger ship with a capacity of 25 people, there are 16 workers who are directly involved in its activities.Details of the number of workers can be seen in table3.1.whereeach position has a different job.
Labor Productivity in the Pre-Work Sampling Stage .2: Tabel 3.2

Tabel 3.3
Presentase of Productive and Non Productive

Tabel 3.5
Recommendations for the Number of Workers using WLA

Table 3 .
6is the result of complete recommendations based on workloads using the Workload Analysis method.The recommended number of workers is 21 people so that no workforce has an excessive workload.If the initial workforce is 16 people, 5 additional workers are needed to match the recommended number of workers.Tabel 3.6 Additional of Worker Using WLA Method Recommendations for the Number of Workers using NASA-TLX Tabel 3.7