I'm less certain on the payment part, but having a very accurate bathymetric survey of the entire path is important for inter-continental submarine fiber optic

I'm less certain on the payment part, but having a very accurate bathymetric survey of the entire path is important for inter-continental submarine fiber optic cable laying. The cable ship needs to know precisely what speed to maintain at every point in the path and how rapidly to pay out the cable for it to not lay taut across underwater valleys, and to conform to the shape of the bottom.