Confidence and reliability are key criteria for the potential introduction of innovative joining techniques. This is, in particular, also true for the modern maritime industry. Scientists of the Fraunhofer IWS have developed a novel, low heat-input but highly efficient laser welding technology for joining processes of up to 50 mm thick parts made of seawater-resistant aluminum alloys. A decisive advantage of this technology is the comparatively low laser power (< 4 kW) needed during the welding of thick metal sheets. The low laser power enables extraordinarily small weld seam widths and minimal component distortion. The IWS laser multi-pass-narrow-gap welding technology (laser MPNG) has been successfully certificated by the classification society DNV GL and is thus now ready for potential industrial applications.