Quarrystone. Quarrystone, a durable and time-tested material for shore protection, should always
be considered where locally available. The structural form of a stone groin is the same as for a stone
Longard Tubes. Longard tubes have performed fairly well as groins as long as they nave remained
intact (Figure 49). Failure has usually resulted from holes or tears in the fabric and loss of sand fill.
Longard tubes are probably best as a short-term or emergency measure because of their vulnerability to
damage. When used as a groin, the tube should be underlain by a filter cloth with 10-inch tubes factory-
stitched to each side. The filter cloth helps to prevent settlement, and the small tubes hold it in place.