Showing papers in "International shipbuilding progress in 2019"

Wet-deck slamming loads and pressures acting on wave piercing catamarans

Abstract: Background: The wet-deck height and centre bow configuration in wave piercing catamarans are critical design factors which influence slamming occurrence and severity. Objective: In this paper, the wet-deck slamming loads and pressures acting on a 112 m catamaran with a centre bow were investigated in regular waves in two wave heights. Methods: A 2.5 m hydroelastic model with three alternate configurations of wet-deck vertical clearance was tested at a speed of 2.89 m/s (38 knots full-scale equivalent). Results: The results showed that at the instant of slamming the centre bow immersion depth relative to the undisturbed incident wave elevation was less than two thirds of the maximum immersion depth during the wet-deck slam event. The location of maximum slamming pressure was found to be in the range between 77% and 80% of the overall length from the transom. The relationship between the relative velocity at impact and slamming force indicated that slamming loads in the order of the vessel weight can occur for the parent design when the relative velocity at slam is about a quarter of the forward speed. Conclusions: Overall, increasing the wet-deck height was more beneficial for reduction of slamming loads and pressures in smaller waves than in large waves.

E-inspection: Effect of continuous hull monitoring on ship safety and crew workload

Abstract: Crewmembers are exposed to high work pressure. Pressure on freight tariffs motivates cost reduction in manning and maintenance, whilst societal developments show decreasing tolerances towards incidents. In conjunction with the developments towards autonomous shipping, the need for continuous and unmanned inspection increases. Considerable progress had been made with respect to monitoring machinery condition, however, the hull structure is as relevant for inspection and maintenance. This will require enhanced inspection, i.e., E-inspection. For hull structure corrosion and fatigue are of main interest. The application of E-inspection, directs the work effort from the crew to the location of interest, at the right time. It gives also the option to monitor the health status of a ship from shore. This paper summarizes the Einspection methods, as identified in the SAFEPEC European project, and how they will help the crew reducing inspection workload.