STUDY ANALYSIS OF THE USE OF HDPE PLASTIC AS A SHELL ON CATAMARAN HULL

This research will study the application of HDPE plastic as a substitute for boat shell on catamaran vessels. The boat was built by traditional vessel craftsmen from Kebondowo Banyubiru. The purpose of this research is to look at the performance of catamaran vessels that include resistances, stability and motion of the vessel. Apart from these technical factors, a strength analysis of the keel profile of HDPE plastic coated wood was also carried out using BKI standards.The method used in this research is to look at the performance of the vessel in question based on differences in the value of the ratio of the distance between demihull and length of the vessel (s / L). The stability value will be measured according to the IMO MSC 36 criteria (63) and the movement will be assessed according to NORDFORSK 1987. The results showed that the smallest resistance value was obtained under conditions of the ratio of demihull distance s / L = 0.42, which is 1.19 kN. The condition of the stability of the catamaran and the motion in all variations has met all the predetermined criteria. The biggest rolling deviation occurs at heading 90 ° at 1.11 ° for vessels variation 1 (S / L 0.32), the biggest pitching at heading 180 ° at 1.09 ° for all variations of demihull distances on the slight medium wave, and the biggest heaving at a 180 ° heading of 0.214 ° for all hull distances on the slight medium wave. The addition of a layer of HDPE material to wood gives an average strength increase of 17 % for a ratio of h/b 1.5 and 8 % for a ratio of h / b = 2. The results of these calculations meet the strength criteria according to Rules BKI.