Mapping and assessment of mangrove environment are crucial since the mangrove has an important role in the process of human-environment interaction. In Indonesia alone, 25% of South East Asia's mangroves available are under threat. Recognizing the availability and the ability of new sensor of Landsat data, this study investigates the use of Landsat ETM + 7 and Landsat 8, acquired in 2002 and 2013 respectively, for assessing the extent of mangroves along the South Sulawesi's coastline. For each year, a supervised classification of the mangrove was performed using open source GRASS GIS software. The resulting maps were then compared to quantify the change. Field work activities were conducted and confirmed with the changes that occurred in the study area. Considering the accuracy assessment, our study shows that the RGB composite color-supervised classification is better than band ratio-supervised classification methods. By linking the open source software with the Landsat data and Google Earth satellite imagery that is available in public domain, mangroves forest conversion and changes can be observed remotely. Ground truth surveys confirmed that, decreases of mangroves forest is due to the expansion of fishpond activity. This technique could potentially allow rapid, inexpensive remote monitoring of cascading, indirect effects of human activities to mangroves forest.

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Kecelakaan KMP. Lestari Maju yang terjadi pada tanggal 3 Juli 2018 mengakibatkan jatuhnya korban jiwa. Kecelakan tersebut diakibatkan oleh air yang naik ke geladak kendaraan karena gelombang tinggi. Jatuhnya korban jiwa diakibatkan kurangnya pemahaman penumpang terkait prosedur keselamatan di atas kapal saat terjadi kecelakan. Hal ini didasarkan dari hasil penyelidikan KNKT yang menjelaskan bahwa penumpang panik dan terjadi perebutan jaket penolong sehingga beberapa penumpang tidak sempat mengenakan jaket penolong. Padahal berdasarkan data fasilitas keselamatan di atas kapal, jumlah jaket penolong mencukupi untuk jumlah penumpang yang ada saat terjadi kecelakaan. Selain itu, tidak ada instruksi dari awak kapal untuk terjun ke laut sehingga penumpang menyelamatkan diri masing-masing. Bahkan ada yang terjun ke laut tanpa mengenakan jaket penolong. Dari hasil investigasi KNKT tersebut pula ditemukan bahwa awak kapal tidak pernah melakukan pelaksanaan safety drill terutama pelatihan keselamatan orang meninggalkan kapal (abandon ship). Kurangnya penerapan ISM Code dan pengawasan terhadap kinerja awak kapal berimbas pada kurangnya kesigapan awak kapal pada saat terjadi kecelakaan. Melalui kegiatan ini dilaksanakan sosialisasi prosedur keselamatan di atas sarana angkutan penyeberangan Bira-Pamatata. Sebelum dilakukan sosialisasi, terlebih dahulu dilakukan survey untuk mengetahui kondisi eksisting alat keselamatan di atas kapal dan juga untuk mengetahui informasi yang belum terkomodir dalam prosedur keselamatan di atas kapal. Berdasarkan hasil survey yang dilaksanakan, diketahui bahwa sekitar 45% responden menggunakan jasa angkutan penyeberangan tidak lebih dari tiga kali dalam dua tahun terakhir. Responden tersebut umumnya memiliki pemahaman yang relatif rendah terhadap prosedur keselamatan di atas kapal. Untuk itu pelaksanaannya harus dilaksanakan setiap kapal akan berangkat.  Berdasarkan hasil evaluasi, pemahaman responen cenderung memaik setelah dilakukan pelaksanaan sosialisasi.

The effect of weight distribution on hydrodynamics factors in the weather criterion was investigated. Two types of weight distribution were examined. With the first type of distribution, the weight was concentrated near the centerline of the model. With the second, the weight was positioned farther from the centerline in order to obtain a natural roll period corresponding to that provided by the standard formula in the weather criterion of the International Maritime Organization (IMO). The three-step procedure recommended by the IMO was applied. A roll decay test and a roll test in a regular beam wave were conducted to obtain the natural roll period, the damping factors corresponding to the breadth-to-draught ratio and the bilge keels, and the effective wave slope coefficient. The damping factor corresponding to the breadth-to-draught ratio for the ship with a larger radius of gyration was larger than that for the ship with a smaller radius of gyration. The ship with a smaller radius of gyration had a larger damping factor due to bilge keels compared to the ship with a larger radius of gyration. The effective wave slope coefficient of the ship with the larger radius of gyration was larger than that for the ship with the smaller radius of gyration. The effect of bilge keels on the effective wave slope coefficient for the ship with a radius of gyration equal to that obtained by the weather criterion formula was not significant. The effect of weight distribution on the weather criterion was significant for the ship without bilge keels. A significant effect of bilge keels on the weather criterion occurred for the ship with a weight distribution corresponding to a radius of gyration coefficient closer to that obtained by the formula in the weather criterion.

No abstract