The method described in the present article doesn't rely on rotating propellers that produce vibrations, thereby reducing one of the major sources of noise.
> method described in the present article doesn't rely on rotating propellers that produce vibrations, thereby reducing one of the major sources of noise
The main source of “hull vibration and noise” from propellers is cavitation [1]. Laser propulsion directly cavitates.
It sounds like it's basically a gigantic cavitation noise generator, so yeah, I'm not imagining that it could possibly be quieter.
Today's submarines go to great lengths to avoid cavitation for just that reason.
Typically there's a velocity beyond which the vessel does not go if it wants to remain stealthy, as going faster than that drastically increases the cavitation noise.