Lonqard Tubes. A Longard tube is a patented, woven polyethylene fabric tube, tilled with sand
at installation, and available in two diameters (40 and 69 inches) and in lengths up to 328 feet (Figure
17). Proper performance depends on the device remaining intact and completely filled, in which case,
the tube is very heavy, yet flexible enough to settle if depressions occur. A properly installed Longard
tube bulkhead is placed on a woven filter cloth extending 10 feet seaward of the tube. A small 10inch
tube, factory-stitched to the seaward edge of the filter cloth, can settle into the bottom under wave action
to provide toe protection.
The primary advantage of a Longard tube is the ease and speed with which it is filled once
equipment and materials are in place. Repairs can be made by sewing on patches. The major
disadvantage is its vulnerability to vandalism and damage by water-borne debris. A sand-epoxy coating
can be applied to dry tubes after filling to provide significantly greater protection against puncturing.
Unfortunately, the coating cannot be applied to a wet tube. Another disadvantage is that a large supply
of good quality sand is required to fill the tube. Patented filling equipment must be mobilized at the site
before filling can begin, and only qualified personnel can perform the work.