Abstract: A boat hull cleaner having a handle (not shown) and a knuckle (see FIG. 1), the knuckle 1 having a first portion 2 and a second portion 3, the first portion 2 having a first channel and the second portion 3 having a second channel, the first portion 2 having a first connector part 4 to be joined to a first tubular part of the handle, and the second portion 3 having a second connector part 5 joined to a second tubular part of the handle; the arrangement being such that a fluid can be caused to flow within the first tubular part of the handle, into the first and second channels of the knuckle 1, and then into the second tubular part of the handle, and wherein the first and second portions 2 and 3 of the knuckle 1 can be adjusted with respect to one another such that the first and second tubular parts of the handle assume an angle with respect to one another.