Hydro-Pneumatic fenders are primarily used for berthing submarines and vessels that have low free board and high draft, which may result in fender contact below the waterline.
Hydro-Pneumatic Fenders are designed and manufactured to be stronger and more durablethan standard pneumatic fenders due to added pressure requirements. The fender is partially water-filled and, then pressurized with air and ballasted to ensure the fender stays at the designed draft line, allowing it to operate efficiently in submerged conditions. The volume of the water within the fender is closely related to the reaction force, guaranteed energy absorption and minimum endurable pressure.