In case of oil pollution to the sea surface, the oil will be recovered and stored in tanks in the oil recovery ships until it can be delivered to recovery stations on land. Experience from such situations has shown that the oil must be heated to maintain a sufficient viscosity for offloading. To ensure that the recovery vessels can operate efficiently, NOFO (Norsk Oljevernforening For Operatørselskap) have made regulations requiring a sufficient heating system for the tanks on board. Presently, such oil tanks are heated by steam from a boiler on board. The steam is in many cases delivered to several nozzles installed around the perimeter of the tank. To achieve an adequate distribution of steam and heat in the tank multiple nozzles must be installed.