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.
