Abstract: A method and system for restoring flow capacity to a submerged fluid conduit comprising a laser light apparatus to generate blue laser light to be impinged on the fluid conduit. The method and system include a frequency multiplier (15) for converting infrared laser light from a laser light generator (14) to blue laser light having a higher transmissivity in seawater. The frequency multiplier may be disposed on a submergible vehicle (2). In one embodiment, a non-submerged infrared laser light generator (14) supplies, via optical conduits (21), laser light to a submerged frequency multiplier (15) on the vehicle (2). Blue laser light, at a wavelength in the range of 440-500 nm, is emitted through an optical window and through seawater to impinge on the surface of the fluid conduit.