Abstract: An apparatus for cleaning the underwater portions of a boat having at least one cleaning unit with an ejection element for generating a jet of cleaning fluid under high pressure, and a manifold for generating jets of gas under low pressure. The manifold enables a space to be defined around the cleaning fluid jet in which space density is considerably reduced relative to the density of the surrounding water, such as a space that is free or practically free from water; this space extends from the ejection element to the surface for cleaning of the underwater portions. The apparatus is applicable to cleaning boats, such as sail boats, motor boats, and canal boats, without it being necessary to take them out of the water.

Abstract: The invention relates to apparatus for cleaning the underwater portions of a boat. The apparatus is remarkable in that it comprises at least one cleaning unit (1) comprising first generator means (10) for generating a jet of cleaning fluid (103) under high pressure, and second means (11) for generating jets of gas under low pressure, said second means (10) enabling a volume (114) to be defined around said cleaning fluid jet (103) in which space density is considerably reduced relative to the density of the surrounding water, such as a space that is free or practically free from water, said space (114) extending from said first generator means (10) to the surface for cleaning of said underwater portions (2). The invention is applicable to cleaning sail boats, motor boats, canal boats, without it being necessary to take them out of the water.