as a two, three or four-boat maximum rafted mooring load. This willhave an important bearing on the minimum sizes <strong>and</strong> capacities <strong>of</strong> thebuoys, hardware, connections, mooring rodes <strong>and</strong> anchors. It will alsohave a bearing on the assessment <strong>of</strong> the bottom conditions <strong>and</strong> itscapacity to hold various types <strong>of</strong> anchors under the design loadsanticipated. The moorings approved for rafting should be markedaccordingly, including the maximum size <strong>and</strong> number <strong>of</strong> rafted boatspermitted.C8.4.5 Moorings should be fabricated <strong>of</strong> highly corrosion resistant materialsthat will st<strong>and</strong> up in wet environments over a long service life. The extraexpense <strong>of</strong> using stainless steel, bronze, fiberglass <strong>and</strong> polyethylene materialswill more than be balanced by the reduced maintenance costs. However,corrosion resistance must not be provided at the expense <strong>of</strong> strength <strong>and</strong>toughness. For example stainless steel hardware for some <strong>of</strong> the connectionsmay not be strong enough for the applied design loads. Galvanized steel partsmay be a more feasible <strong>and</strong> reasonable alternative. The selection <strong>of</strong> propermaterials is critical to a well functioning <strong>and</strong> long lasting mooring system.C8.4.6 It is imperative that mooring systems be inspected <strong>and</strong> maintained on aregular scheduled basis. The boating public should be confident that mooringsused are completely adequate for the size boats being moored, <strong>and</strong> that themoorings will function safely <strong>and</strong> reliably under all reasonable conditions for thesite. Maintenance should include annual raising <strong>of</strong> the anchors, rodes <strong>and</strong>buoys for visual inspections, repairs <strong>and</strong>/or replacements.C8.5 ConnectionsC8.5.1 All connections on a boat mooring should be <strong>of</strong> high reliability <strong>and</strong>trustworthy for public use. Moment developing connections should be avoidedto prevent repetitive twisting <strong>and</strong> bending <strong>of</strong> mooring components that wouldlead to fatigue <strong>and</strong> eventual failure. A maximum degree <strong>of</strong> freedom should beprovided at each connection through the use <strong>of</strong> a clevis, swivel, connecting links<strong>and</strong>/or short lengths <strong>of</strong> chain.CC8.6 Environmental ConsiderationsC8.6.1 As the scope <strong>of</strong> a mooring increases, the length <strong>of</strong> the rode increasesas well, resulting in a progressively larger potential area <strong>of</strong> disturbance <strong>of</strong> thebottom. A swing boat mooring has a 360 o circular potential area <strong>of</strong> disturbancewith the anchor at the center. As winds <strong>and</strong> currents change direction, the buoy<strong>and</strong> a moored boat swing the rode, possibly creating <strong>and</strong> maintaining adisturbed circle on the bottom. All <strong>of</strong> this is dependent on the depth <strong>of</strong> the water,<strong>and</strong> the type <strong>and</strong> length <strong>of</strong> the rode. In the case <strong>of</strong> fore <strong>and</strong> aft moorings, theegg-shaped area <strong>of</strong> potential bottom disturbance is much smaller, being limitedto lateral movement allowed by rode length <strong>and</strong> water depth. Site conditions willdictate which type <strong>of</strong> mooring is appropriate, safe <strong>and</strong> reliable.SECTION C Berthing - Page 35
C8.6.2 It may be difficult to obtain environmental permits from federal <strong>and</strong> statepermitting agencies to install <strong>and</strong> operate mooring buoys that disturb the bottom<strong>of</strong> a waterway. Prior to the installation <strong>of</strong> buoys, permits are needed from local,state <strong>and</strong> federal agencies that have jurisdiction.C8.6.3 Boat mooring alternatives that minimize bottom disturbance should beused wherever possible, provided the safety <strong>and</strong> integrity <strong>of</strong> the mooring systemis not compromised. To avoid dragging <strong>of</strong> mooring rodes on the bottom, flexibleelastic rodes can be incorporated into the design, essentially acting as largerubber b<strong>and</strong>s that stretch under load <strong>and</strong> contract when the load lessens. If theenvironmental bottom disturbance issue is not addressed in a permitapplication, a permit might not be issued <strong>and</strong> the proposed moorings might notbe approved for installation <strong>and</strong> operation.NOTESSECTION C Berthing - Page 36
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