Oceanographic studies as the basis for shipyard development at the Fish Landing Port of Sabang

Shipbuilding is one of the marine industries which in development needs to pay attention to various parameters from the sea and land. This research was conducted in March to May 2022 with the aim of identifying the influence of oceanographic factors and water quality on the development of the shipbuilding industry at the fishing port of Sabang City. The oceanographic data used includes tides, wind, bathymetry


Introduction
A modern shipyard is an entity involved in shipbuilding, ship repair, ship modification, and other marine-related works.Managing these activities requires specific skills and knowledge.Ideally, a modern shipyard is equipped with facilities that support the shipyard performance, such as slipway, graving docks, and floating dock.The shipyard industry also uses airbags as a ship launching method by utilizing rubber filled with air for the launching and ship docking process.The modern shipyard industries currently implement the modular construction approach in shipbuilding.Ships were designed and built based on the modular approach.This approach means that the module was built in a particular location and transported to the building location for the final line up then combined.Thus, the shipyard will only focus on the core area for shipbuilding instead of the whole process starting from designing to launching (Abdullah, 2016).The modern shipyard industry has a better management system compared to conventional shipyards.Structured documentation aims to have specific documents with relevant information for each assembly phase (Maltuja et al., 2018).
Before developing a shipyard in a port, it is crucial to assess the location suitability based on oceanographic factors, such as currents, seawater depth, wind, wave, tide, and sedimentation.Current speed, wind, and wave height are crucial for shipyard development because they can impede the exiting and entering of ships into the docking pool.These factors can cause sedimentation and impact the docking pond silting.Zaman et al. (2019) Rizwan et al. (2023) several oceanography parameters, such as currents, bathymetry, wave, wind, and tide, influence the shipyard location.
Of these factors, wind speed and wave height play an important role because they can interfere with access to and from the jetty pool.In addition, these three main factors also greatly influence the rate of sedimentation which causes siltation of ponds in the future.
Wind energy can be called another form of solar energy because wind is generated by differences in air pressure caused by the uneven heating of the earth by the sun (Dida et al., 2016).The depth reading is the seawater depth at the time of measurement, while the depth curve included in the depth chart is the depth at the mean sea level reference.When describing a contour using the mean sea level (MSL), the Mean Sea Level (MSL) value must be calculated first (Satriadi, 2012).Sediment is a collection of surrounding rock debris that contains heavy metals determined by the mineralogy of the source rock.In areas affected by human activities, sediments are formed, heavy metal content in sediments is formed under the influence of natural geochemistry and the results of human activities (Permanawati et al., 2016).Tides are caused by the attraction of celestial bodies, the most important of which are the sun and moon.The tides in a place are different from other places depending only on the position of the sun and moon in that place (Novitasari et al., 2018).
Research of the influence of oceanographic factors on shipyard development are still limited because the majority are still oriented to shipyard productivities (Kyaw et al., 2017), facilitation layout (Choi et al., 2017), production capacity (Lai et al., 2020), as well as management and planning (Singgih, 2019).This research aims to assess the water quality around the fishing port and its' relevance in shipyard development and investigate the influence of oceanographic factors on shipyard industry development in Sabang Fishing Port.

Materials and Methods
This research was conducted during March to May 2022 in Sabang Fishing Port and Laboratory of Marine and Fisheries Faculty, Syiah Kuala University, at vertical and horizontal distances of 120 m and 310 m, respectively.The area of this research area is divided into 12 points scattered along the coastline.Data analysis was performed on oceanographic factors and water quality.The oceanographic factors were tides, wind, bathymetry, and sediment composition.The tidal, wind, currents, and waves data around the sampling sites for the last three years were collected from the Meteorological, Climatological, and Geophysical Agency.Furthermore, water depth samples were collected by emitting eco sounder/fishfinder waves to the waters.The depth of the waters in the study area ranges from 20.7 to 51.59 meters.On a bathymetric map (see Figure 3), shallow and deep waters are illustrated using light blue and dark blue.The area with a depth of 51.59 meters is in the middle of the bay, while the shallow area is close to the shoreline near the pier.

Sediment
Based on the Wentworth scale below (see figure 4) four categories of sediment are found in Sabang Bay, namely gravelly muddy sand, gravelly sand, slightly gravelly sand, and sand.Gravelly muddy sand types were only found at station 4. Gravelly sand types were found at stations 5, 10 and 11.Slightly gravelly sand types were found at stations 3, 6 and 9. Sand types were found at stations 1, 2, 7, 8 and 12. Based on the graph below (see Figure 5), the highest tide recorded in Sabang Bay was as high as 2.8 meters which occurred on the 25th, while the lowest recorded low tide was as high as 2.2 meters which occurred on the 15th.

Discussion
The wind in the waters of Sabang Bay blows northwest with high speeds ranging from ≥10.00 m/s.While the wind with a relatively low (1.00 m/s) to moderate speed, blowing from the southeast to the west.Wind movement will affect the characteristics of the mass of water in the sea, one of which is the change in the direction of surface currents (Robertson and Field, 2008).The depth of the water marked in dark blue in front of the wharf indicates a potential location for ship mooring.On a bathymetric map (see figure 3), the area with a depth  Rizwan et al. (2023) of 51.59 meters is in the middle of the bay, while the shallow area is close to the shoreline near the pier.Besides that, of the 12 observation stations, sandy sediments were the type of sediment that was most commonly found.This is likely influenced by the condition of the waters which tend to have strong currents which face the open sea and the shipping activities which are quite busy causing a high supply of sediment in the area.
According to Manurung et al. (2017) sea waves that propagate toward the coast cause a process of transporting sediment parallel to the coast.This is because the sediment moves along with the more dominant wave motion.In addition, the waves that break also affect variations in sediment types (Azizi et al., 2017).Basically, when the mass of water increases or decreases, deeper water conditions tend to experience a lot of turbulence and agitation.This turbulence causes the suspended material to mix with the floating material and increases the load of suspended particles in the waters.This stirring is the result of the movement of ocean currents which then causes the bottom sediments to be lifted and stirred again (Rizwan et al., 2021).
Based on the graph (see Figure 5), the highest tide recorded in Sabang Bay was as high as 2.8 meters which occurred on the 25th, while the lowest recorded low tide was as high as 2.2 meters which occurred on the 15th.The tides that occur in the bay of Sabang are relatively stable.Tidal characteristics in Indonesia are also influenced by wind direction (Suhana et al., 2018).The tidal system in Indonesian waters is one of the most complex tidal systems in the world because of the bottom topography, variations in coastline and the mixing of the Pacific and Indian Oceans, including the South China Sea (Sverdrup et al., 1942).tides can also affect currents horizontally, while topography affects currents vertically (Angskostan et al., 2017).Tidal currents in shallow and deep water are important for mixing heat and momentum.The main absorber of tidal energy is friction that occurs on the seabed due to the topography of the sea resulting in internal waves (Darruwedho et al., 2016).

Conclusion
Oceanographic factors in Sabang Bay have shown very satisfactory results for the development of fish landing bases.The wind in the waters of Sabang Bay blows northwest with high speeds ranging from ≥10.00 m/s.The depth of the waters indicates a potential location for ship mooring.Sandy sediment is the most common type of sediment found.The tides that occur in the bay of Sabang are relatively stable.

Figure 2 .
Figure 2. Wind pattern in the study area

Figure 3 .
Figure 3. Bathymetry patterns in the study area

Figure 4 .
Figure 4. Sediment Fraction Distribution Pattern at the research station