THE MYTH AND LEGEND OF SADAI AND GASPAR STRAIT BANGKA BELITUNG (BANCA-BILLITON) AND OCEANOGRAPHIC CONDITIONS

Abstract

Sadai strait is located in between of Bangka and Lepar island (Pulo Lepa). Gaspar strait positioned between Bangka and Belitung island was named after the Spanish captain passed through it from Manilla in 1724. Southeast part of Bangka had been called Macclesfield after Captain Hurle in English ship Macclesfield. The myth of many pirates, the legend of many sunken of warship and merchant ships of Chinese, Dutch, Japanese at Gaspar Strait.  The southernmost dangered Fairlie Rock was named and discovered by a merchant company ship Fairlie in 1813 and a more detail examination by Captain Ross at surveying ship Discovery in 1814. A Portuguese ship sail from Macao was wrecked in 1816 at Discovery Rock.  The study aims to build and analyze the bathymetric, current spatial model and tide data to discover the oceanographic characters related to the sunken ships legends.  Measurement based on a hydroacoustic method using single beam echosounder for primary data, GEBCO bathymetric and Landsat-8 satellite for secondary data. GPS coordinate and depth value of x-y-z was processed for a spatial layer using geo-statistical gridding method. A spatial numerical model of current based on data of bathymetry and tide data using the hydrodynamic module to build two and three-dimensional models based on a triangular mesh (system flexible mesh) spatial unit with consideration on the seawater baroclinic condition.  Narrow strait and small islands widely distributed around Gaspar strait as a channel of no escape in the case of sailboat piracy.  Oceanographic variable mainly caused by extremity and  known as the most dangerous ‘Fairli-and Discovery rock’ with narrow and shallow rock bottom morphology especially at low tides and considerable extent of sand-dunes and the north (Natuna island) to south (Bangka-Belitung) seawater volume transport and current pattern interactions seems to be the most dominant and unpredictable situations for ship line safety.