Abstract: A self-contained apparatus for placement of discrete fiber element tows on a mandrel or other tooling. The apparatus carries a spooled fiber element supply, which is directed to a compaction roller over a short, non-convoluted path through a cut/add module having a knife assembly for severing a discrete tow from a continuous fiber element filament, and a drive assembly for feeding the tow and restarting feed of a new tow after severance of the prior one from the filament. The apparatus is particularly suitable for sequentially laying up superimposed, or stacked, tows to define rib-like stiffeners of composite material for reinforcing composite shell structures, and grids of such stiffeners. Methods of using the apparatus are also disclosed.