Case Study 2
6,100 CEU pure car/truck carrier (PCTC) in South Korea

Overview
Dealing with vibration and fatigue issues. SeaQuest was awarded the management of the shipbuilding contract for a 6,100 CEU pure car/truck carrier (PCTC) in a leading South Korean shipyard.

Actions/Risk Mitigation
Fatigue and fracture have long been  important issues for ship and offshore structures. SeaQuest places great emphasis on  assessing the fatigue strength of ships. At the design stage of the project it was found that the area with no side to the side bulkhead in the cargo area was prone to vibration and fatigue cracks during short service periods.

SeaQuest conducted extensive 3D reviews of the ship design and FEM analysis for the expected 30 year life cycle of the vessel. Also, by visiting PCTCs already in service, a fuller picture of this type of vessel’s vibration and fatigue issues was acquired. By undertaking this research SeaQuest changed the structural details and welding profiles to build a far better structurally designed vessel.

However, whilst the vessel was being built it was identified that there were still critical weaknesses in the design, and that inspections needed to be conducted at the sub assembly and block stage. SeaQuest monitored the critical areas cut outs and released all information to all the construction sites of the builder, as well as the sub-contractors. SeaQuest then performed weld profile grinding as recommended by FEM analysis. Once the vessel was in service it was found that there were cracks in the decks, engine room and the accommodation. SeaQuest redesigned the accommodation area, specifically the end connections, corners and cut-outs. We found it important to educate all relevant parties in Quality Management and production with follow up inspections.

Following this project SeaQuest decided that the block fabrication technique sub-contractors needed to be changed, and it was shifted to China.