with water jets and hydraulic vacuum cleaners. The bottom surfaces of some foam floats 

 have intentionally been left uncoated to ensure automatic self -cleaning in seawater. After a 

 few years of incrustation the growth becomes heavy, tears loose and drops to the bottom. 

 When this occurs, a small amount of foam wiU be removed, but not enough to cause 

 appreciable loss of freeboard over the normal hfe of a floating structure. A greater danger in 

 some areas is an infestation of screw worms or other burrowing biota that reduce the 

 effective buoyant volume of the foam. In turn, birds and small animals cause further loss of 

 foam by searching out these worms for food. In areas known to be infested with such 

 burrowing biota, all foam surfaces should be coated. 



Loosening of bolted connections is a major cause of deterioration of floating systems in 

 harbors with more than minimal wave action, especially if the joined components are heavy. 

 Nuts often corrode fast to bolts and cannot be tightened. The resultant differential 

 movements of floats and stringers may then quickly enlarge the boltholes to the extent that 

 both the connecting hardware and the stringers must be replaced. Hinge-connected floating 

 components often stress the hinges severely under wave action. Worn hinges not only 

 become noisy but the resultant peening of metal against metal as stresses are reversed by the 

 wave cycles may accelerate the wear so that the hinges break long before the components 

 become unserviceable. Such peening action may be prevented by inserting block rubber 

 expanders between the ends of the hinged components to keep the hinge continuously in 

 tension. This also eliminates noise, provided the hinge is kept well greased. 



(7) Pile guides in a pile-anchored floating system deteriorate more rapidly than other 

 parts of the system and if not repaired may damage the piles and threaten the integrity of 

 the anchorage system against strong wind or current-induced stresses. When this occurs, the 

 damaged guides should be replaced with heavy-duty roller guides such as the one shown in 

 Figure 86. Two or three guides of this type may satisfy the needs of the system and prevent 

 wear in the other guides that are forced into contact with the piles less frequently because 

 of the pecuharity of the guide-pile geometry system. 



Cable anchorage for floating-shp systems is so variable that no single aspect of such a 

 system can be singled out as being universally prone to early maintenance trouble. Unhke 

 the customary multiple anchorages, cable systems usually rely on not more than three or 

 four cable ties per floating system for maintenance of position. Hence, it is important that 

 all winches, hnes, and anchors be inspected regularly, as one lost anchor or line may allow 

 the entire system to drift and collide with some other object. The results of such a colhsion 

 could be disastrous. 



(8) Utihty hnes and outlets on fixed piers differ sUghtly in maintenance from similar 

 installations on land. On floating piers, however, utility conduits and pipes are usually much 

 closer to the water surface and hence exposed to more wave splash and moisture -laden air. 

 Loose connecting stringers may allow enough flexing along a headwaUc under wave action to 

 break the conduit or pipes if they are attached firmly rather than loosely supported. In 



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