Hovercraft either do, or do not work at all due to the "hump"-phenomenon.
Hump-speed is the speed at which a Hovercraft overtakes its own divot, the air-cushion creates in the sea way immediately in front of the Hovercraft. Hump-speed has its analogy in the speed at which sailing yachts begin to glide. At this speed drag reaches the peak which the Hovercraft needs to overcome to reach its maximum speed. Hump-speed occurs at low-speed of around 8-12 knots, depending on the weather- and wave-conditions. Numerous Hovercraft designs fail to overcome hump-speed even under moderate wheather- conditions despite engines running at full power.
Only Hovercraft with a high power-to-weight ratio offer sufficient performance to easily overcome the hump barrier. Hovercraft fully made from Advanced Composites like the ABS M-10 offer the highest power-to-weight ratio offering an extra margin of performance.