Umoe Mandal - What is a Surface Effect Ship (SES)?

What is a Surface Effect Ship (SES)?

Catamaran side hulls
  • Flexible rubber seals in the fore and aft
  • Air inflow: lift fans
  • Air outflow: ventilation valves (controllable!)
  • A SES rides on an pressurized air cushion
  • …enclosed by side hulls and seals






Umoe Mandal is the global leader in Surface Effect Ship (SES) and Air Cushion Vehicles (ACV) technologies. For both SES and ACV, an air cushion supports most of the weight of the craft. In the case of SES, the air cushion pressure is held within two sidehulls and flexible bow and stern skirts. In the case of an ACV flexible skirts keeps the air cushion pressure. Large powerful centrifugal fans, often called "lift fans" supply the compressed air to the air cushion with sufficient flow rates to keep the pressure when the craft is subjected to wave induced ship motions and at high speed. SES is known to have outstanding seakeeping performance in waves and ACV is the only craft able to cross mudflats and climb dry land. Due to the low wave resistance of these craft at high speed, both SES and ACV can reach extreme speeds with low propulsion power. As an example the SES type Skjold Class is the fastest operational corvette in the world.