The caulking of the hull of the barquettes marseillaises is an essential operation as it guarantees their watertightness. Here led by Denis Borg himself, it consists of stuffing the tow slots between two platings (planks of the outer covering of the hull) with tow. Traditional hemp, which has become unobtainable, is replaced by cotton yarn. The cracks and seams are then filled with a linseed oil paste.