With Wassara you get straight and stable boreholes, thanks to the tight clearance between drill string and borehole. The stability is maintained by the water column's hydrostatic pressure. Also, the low up-hole velocity of the water prevents creation of cavities, which means cleaner and smoother holes.
The low velocity of the return water minimizes the wear on the hammer guide ribs, making it possible to keep a tight clearance between hammer and borehole.
