Ship Track and Speed Model in Case of Steering Gear Breakdown with Rudder Remaining Fix at non Zero Angle

摘要

Plovidba broda određena je položajem broda na određenom dijelu plovnog puta od mjesta polaska do mjesta dolaska. Tijekom plovidbe brod mijenja smjer i brzinu u nekom vremenu. Sama plovidba može se razmatrati s aspekta kada tijekom plovidbe svi sustavi na brodu rade ispravno, a osoba koja upravlja brodom se ponaša kao „dobar pomorac" i s aspekta kada je tijekom plovidbe došlo do nastanka izvanrednog događaja koji utječe na mogućnost održavanja željenog smjera i/ili brzine.rnU ovom radu istraženo je kretanje broda pri nastanku izvanrednog događaja, a pretpostavlja se da je kvar nastao na sustavu kormilarenja. Ovisno o području u kojem brod plovi i količini pomorskog prometa takav događaj generira dva osnovna pomorska plovidbena rizika, rizik nasukanja i rizik sudara. U ovom radu istraženo je kretanje broda koje ovisno o scenariju može rezultirati nasukanjem broda.rnZa potrebe istraživanja kretanja broda zbog pretpostavljenog izvanrednog događaja na brodu definirani su različiti scenariji. Za izradu modela krivulje kretanja broda s obzirom na definirane scenarije izabrana je klotoida. Modificiranjem parametarske jednadžbe klotoide u konačnici se dobila krivulja koja vrlo vjerno aproksimira krivulju kretanja broda. Nadalje, izrađen je model promjene brzine koji može procijeniti brzinu broda u bilo kojoj točki krivulje okretanja broda kada je otklon kormila konstantan, a stroj zaustavljen. Dobiveni modeli ispitani su na 60 scenarija prena kojima je provedeno istraživanje na navigacijskom simulatoru.rnModel kretanja broda može se iskoristiti u području istraživanja za razvoj simulacijskog modela čiji će rezultat omogućiti određivanje veličine oštećenja pri nasukanju, a nakon određivanja posljedice nasukanja omogućit će i definiranje prihvatljivog rizika.%Ship navigation is determined by the ship's position on a certain part of the fairway from the place of departure to the place of arrival. During the voyage, in a given period of time ship changes the course and the speed. Navigation itself can be viewed from the aspect when during the voyage all onboard systems are functioning properly and the person managing the ship practices good seamanship, and from the aspect when an extraordinary event occurs, which affects the possibility of maintaining the desired course and/or speed. This paper analyzes the movement of the ship in case of an extraordinary event with the assumption that the malfunction occurred in the steering system. Depending on the navigation area and the sea traffic, such an event generates two basic maritime navigation risks, the risk of ship grounding and the risk of collision. This paper explores ship movement that, depending on the scenario, may result in ship grounding. For the purposes of conducting research on ship movement due to the assumed extraordinary event onboard, various scenarios were defined. To create a track model, an Euler spiral/clothoid was chosen. By modifying the parametric clothoid equation, a curve was obtained which very well approximated the curve of a turning ship. Furthermore, developed was the speed change model that can show the speed change at any point of the curve of a turning ship when the rudder deflection was constant, and the engine was stopped. The designed models were tested in 60 scenarios in accordance to which the research on the navigation simulator was carried out. Ship track model can be used in the field of research for simulation model development, the result of which will enable determining the extent of grounding damage, and after determining the extent of grounding consequences, it will enable the defining of acceptable risk as well.