In every implementation of the project, work accidents can occur which result in injury or other losses. One of the projects that has the potential for work accidents is the floating dock construction work. The purpose of writing this paper is to find out the dominant hazard variable in floating piers and breakwater construction work, to know the causes and effects of the dominant hazard variable, and to know the right dominant risk control risk control in floating wharf construction work. This research begins with hazard identification using several sources and also direct discussions with resource persons who understand this work. Then a questionnaire was distributed to obtain the likelihood and severity values of the existing hazard variables. From the results of distributing the questionnaires, tests were carried out using validity and reliability tests on each hazard variable that might occur. The results of the tests carried out obtained a valid hazard variable and were then analysed using HIRA which was assisted by a risk matrix. So that the results of the analysis are known to be the dominant hazard variable, namely workers falling and sinking into the sea. Furthermore, an analysis of the two variables is carried out to determine the causes and also the impact of risks that can occur using a bow-tie diagram to reduce the occurrence of dominant potential hazards. © Published under licence by IOP Publishing Ltd.