in which zone the dewatering equipment 30 is placed is usually within the range of l 2 m to 6 m a so called wedgewise narrowing gap is usually used as the gap k the length of the gap k as calculated from a plane extending through the axes of rotation of the breast rollers 11 and 21 up to the line a may be from less than 0 5 m to about 1 m the operation of the gently curved forming zone d placed at the forming board 30 and the dewatering equipment provided within the zone d are hereinafter described with reference to fig4 to 7 generally speaking the zone d consists of one or several deck surfaces tensioning the wires 10 20 with a curve radius r the openness of the deck surface varies from an almost closed curved deck to a highly open deck construction assembled from rib like members for example in any case even the individual ribs or deck surfaces are grouped so as to provide the wires 10 20 in the forming zone d with a relatively gentle curve radius r which is as hereinbefore stated usually within the range of r 5 m to 50 m preferably 10 m to 20 m thus the centrifugal forces acting in the forming zone d remain low even at high velocities v the dewatering and formation are promoted in the zone d by the pressure pulsation generated by the alternate open spaces and closed deck surfaces the forming board 30a shown.