A boat hull comprising a bottom panel that makes up the bottom of the boat hull. It consists more precisely in a process for oxidizing hydrocarbon, alcohol andor ketone, using oxygen or a gas containing it, in liquid phase and in the presence of a catalyst dissolved in the reaction medium, characterized in that the catalyst comprises a soluble manganese compound and at least one soluble chromium compound. A holder has a window portion through which the camera IC portion is passed and a cover portion which covers the camera unit and which has ribs engaging with the respective rib slots. Prior to the rod being inserted, therefore, the screw head remains polyaxially free with respect to the coupling element and the body.