Maneuver Control System for Collision Avoidance Based on Experimental Study
3. Results Analysis and Discussion 1. Ship and obstacle trajectory
From the test results by using Qualysis camera, the ship trajectory graphic (x axis, y-axis) at 250 m, 200 m and 150 m.
Figure 12. Ship and obstacle at distance of collision 250 m, 200 m and 150 m
3.2. Distance from ship to obstacle
From the trajectory of the ship and the obstacle in Fig.
12, we can find the distance between the two points of the ship's trajectory point (x-axis, y-axis) and the point of the obstacle (x-axis, y-axis). The z-axis on the ship and the obstacle is not counted because during the test the ship moves on the axis of the 2D axis is the X and Y axis. The formula for finding two points is as follows:
Distance = difference x2 +difference y2 (1)
=
(
x2−x1) (
2+ y2−y1)
2 (2)Where:
x1 = Value X Obstacle x2 = Value X Ship y1 = Value Y Obstacle y2 = Value Y Ship
From Eq. 2, we can calculate the distance between the two points that is x-axis, y-axis of the ship’s trajectory and x-axis, y-axis obstacle at 250 m, 200 m and 150 m. The results shown in Fig. 13.
Figure 13. Distance from ship and obstacle at distance of collision 250 m, 200 m and 150 m
Figure 11. QTM
69 4. Conclusion
From the results of measurement and analysis of test results it can be taken a conclusion. Based on the experimental results it is found that the design of maneuver controls installed in the model of fast patrol boats during the test, may prevent the ship from occurring collisions.
Ships at 10 knots can avoid collisions at 250 m, 200 m and 150 m in non-disturbance conditions. The closest distance between the ship and the obstac le at a distance of 250 m is 34.17 m at T = 16 seconds, at a distance of 200 m is 13.46 m at T = 17 seconds and at a distance of 150 m is 13.36 m at time T = 17. This distance is obtained when the ship is adjacent or side by side with obstacles.
References
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Regulations of Collision Avoidance.,” Adv. Sh. Des. Pollut. Prev., no. 1999, pp. 205–216, 2010.
[2] M. Iqbal, R. Nugraha,“Design Boat Control System for Collision Avoidance,” e-Proceeding Universitas Telkom, vol. 4, no. 2, pp.
1426–1433, 2017.
[3] A. S. Aisjah, A. A. Masroeri, M. A. Efendi, E. B. Djatmiko, W. D.
Ariyawan, and F. A. Iskandarianto, “Fuzzy Control for Optimizing Ship Tracking in Karang Jamuang – Tanjung Perak,” The Journal for Technology and Science, vol. 23, no. 4, pp. 118–125, 2012.
[4] M. Ridwan, A. S. Aisjah, “Prototype Design of Control Systems Tracker Tracks on Unmanned Vessel Using Fuzzy Logic,” Jurnal Teknik. Elektro ,no. 1, pp. 1–8. 2014.
[5] E. Freaks, “HC-SR04 User Guide,” Elec. Freaks, pp. 1–6, 2011.
[6] Studuino, “Studuino Gyroscope.” Environment and Software, pp. 1-15, 2012.
[7] Ats, “Advanced Telemetry Systems - Manual Tracking,” pp. 1–5, 2009.
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Volume 1, Number 2, August 2018, pp. 70-73
eISSN 2621-0541DOI: 10.25042/epi-ije.082018.11
70
In Use of Permeable Groin for Reducing Longshore Sediment Transport at Tanjung Bayang Beach of South Sulawesi
Hasdinar Umara,*, Sabaruddin Rahmanb, Chairul Paotonanc,Ahmad Yasir Baedad
a Department of Coastal Engineering/Laboratory of Coastal Engineering, Faculty of Engineering, Universitas Hasanuddin. Email: [email protected]
b Department of Coastal Engineering/Laboratory of Coastal Engineering, Faculty of Engineering, Universitas Hasanuddin. Email: [email protected]
cDepartment of Coastal Engineering/Laboratory of Coastal Engineering, Faculty of Engineering, Universitas Hasanuddin. Email: [email protected]
d Department of Coastal Engineering/Laboratory of Coastal Engineering, Faculty of Engineering, Universitas Hasanuddin. Email: [email protected]
Abstract
Breaking wave near beaches is the main force to generate longshore currents, which moved the sediment at surrounding area. Due to its negative outcome, which are erosion and sedimentation, the need of longshore sediment transport analysis become very important. One of the tools for solving that problem is by using coastal protection structure such as permeable groin. Permeable groin may reduce the rate of longshore sediment transport respectively by changing the level of permeability of the groin itself. The objective of this research was to obtain analytical results of the longshore sediment transport reduction analysis by using permeable groins at Tanjung Bayang Beach of South Sulawesi. Reduction of sediment transport along the beach was analyzed by calculating reduction coefficient, which is the ratio between the longshore current before and after hitting the permeable groins. The result showed that with 40% of permeability, the groin can reduce longshore sediment transport at Tanjung Bayang Beach for almost 50%; from 341.37x103 m3/year to 170.68x103 m3/year.
Keywords: Permeable groin; reduction; sediment transport
1. Introduction
Erosion and sedimentation solemnly occurred on some beaches in Indonesia. For example, the erosion occurred in the beach of Teluk Segara Bengkulu City due to crib from the old port of Bengkulu [1]. The crib blocked the longshore sediment transport to the east. Junarsa [2] stated that the erosion occurred in Pantai Pasaruan Serang occurred due to the sediment transport. Umar [3] analyzed the longshore sediment transport at Glagah Beach, Central Java was 343,32,103 m3/year (west direction). If permeable groins were used with density of piles groin (p) 40% then it could reduce the longshore sediment transport up to 166.36.103 m3/year. Reduction of longshore sediment transport can be determined using the parameter of reduction coefficient [3]. Groin was effectively as sediment traps in the longshore direction and coastal stability buildings at Teluk Penyu Beach. The pattern of coastal line change of Teluk Penyu Beach for 5 years (2014 - 2019) has accretion but tends to be stable with the same value of equal accretion and erosion that was equal to 421 m2 and
408.56 m2 [4]. Suswanto [5] determined the critical points of erosion and arranged concept of erosion prevention which considered as a few alternatives of cost protection structure such as groin, breakwater and also recommendations needed to treat Teluk Penyu Beach comprehensively. The cross-shore sediment transport was dominant to the west and longshore sediment transport was to the south. It caused in Akkarena Beach having significant erosion, especially in the area around the estuary [6].
Problems that occured in Tanjung Bayang Beach were the large sedimentation in the upstream of the Jeneberang estuary then emptied at Tanjung Bayang Beach. To overcome the problem, the use of permeable groin as a controller of the longshore sediment transport, was proposed. This paper will discuss and analyze the reduction process of longshore sediment transport by using permeable groin at Tanjung Bayang Beach, South Sulawesi.
*Corresponding author. Tel.: +62-811-416-5078 Jalan Poros Malino km. 6, Bontomarannu Gowa, Indonesia, 92171
71 2. Permeable Groin
The permeable groin has a split structure so that the longshore current can passed through the structure and the sediment can still be transported to the other side. The longshore currents and longshore sediment transport, which flowed through the permeable groins can be controlled by the gap density of the permeable groin structure itself. The widely used permeable groin was a piles groin, one of which was in Raudkivi [7] that examined the use of groin piles on the coast of Baltic Sea. Permeable groin used to reduce the longshore currents and longshore sediment transport but can still provide sediment supply to the other side of groin, which also called down drift groin. The longshore current reduction that occurs after the groin piles can be seen in Fig. 1.