window space is required for the necessary circulation and wave transmission through the 

 windows defeat the purpose of the barrier. Where only a single diaphragm is used, the best 

 means of achieving some water circulation without increasing wave transmission to 

 unacceptable limits is to carry the solid sheathing about three-fourths of the way to the 

 bottom and leave the bottom one-fourth completely open except for supports. This will 

 effect a high degree of attenuation of short-period waves, and although it will still allow the 

 longer-period waves to regenerate, a satisfactory fraction of the circulatory currents will pass 

 under the barrier. 



If a fixed barrier is impractical because of depth problems or lack of space, some degree 

 of wave protection can be achieved by a continuous drop panel on the outside of a floating 

 walkway, along the margin of the fairway from which protection is sought. Where a series of 

 fixed or floating piers extends out to a main channel, a frequently used alternative is to 

 attach drop panels to the end fingers (Fig. 38). To be reasonably effective, the panels should 

 extend at least 6 feet below the water surface. 



A good way to ensure that troublesome boat-wake waves will not enter the berthing area 

 is to design the harbor so that heavily traveled fairways or channels are separate from the 

 berthing areas (Sorensen, 1973). Separation of basins from channels can be done by 

 geometric arragement of the interior water areas. The layout of Marina Del Rey, discussed in 

 Section VIII, is a classic example of basin separation by moles. 



d. Berthing Facility Arrangements. The oldest methods of securing unattended small 

 craft are anchor moorings and beachings. Any type of anchor mooring, from single-point 

 free-swinging to multiple-anchorage ties, results not only in the inefficient use of space, but 

 the need for shoreboats in transferring personnel between the moored craft and shore. 

 Beachings are not only difficult for larger craft, but take up considerable perimeter area. For 

 these and perhaps other reasons, neither anchor moorings or beachings appear compatible 

 with modern marina operations except in a few isolated cases. 



When a visiting craft arrives at a small-craft harbor it is normally docked alongside a float 

 or fixed pier near the harbormaster's office, and the owner proceeds to make his 

 arrangements for temporary berthing or for a longer-term slip rental. The first type of 

 facility, the landing dock, requires alongside breasting of the craft, usually with ties to 

 mooring cleats or curb timbers on the dock foreand-aft of the boat. This type of docking is 

 not suitable for long periods of unattended berthing; the constant differential movement of 

 boat with the dock may cause huU abrasion or may accelerate wear on a fendering system. It 

 is used, therefore, only for short stays, like at a fueling dock. One exception is the trailing 

 floating sUps sometimes used in flowing rivers (Fig. 7), which can only be used satisfactorily 

 in conjunction with alongside dockage. 



In a boat slip, the craft may be tied away from the dock structure, usually with 

 fore-and-aft ties on both sides. In a single-boat slip, the craft is flanked on each side by a 



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