vandalism or waterborne debris. Figure 37 shows before and after views of a Longard tube slashed by
vandals. The damage eventually caused the entire tube to deflate.
Sand-Filled Bags. This breakwater is built using stacked bags in a staggered pattern (Figure 38).
The structure's performance depends on whether the individual bags remain in place and intact. The bags
and seams must be resistant to ultraviolet light to preclude deterioration from prolonged sunlight
exposure. The lighter bags (100-pound range), such as those used for revetments, are displaced when
exposed to even moderate wave heights. Larger bags, therefore, such as Dura Bags are recommended for
breakwaters even though they are more difficult to handle and must be filled in place. A filter cloth
should be placed under the bags to reduce settlement in soft bottoms. During construction, bag-to-bag
abutment should be insured to preclude wave transmission through gaps.