provided where the buried lines emerge from the basin perimeter. If the docks are floating, 

 flexible hose connections are needed at each end of the gangway. The hose should always 

 attach to a downward facing pipe end and hang in a U-shaped loop to prevent early fatigue 

 failure (Fig. 102). In galvanically active soils, buried pipe requires either a corrosion resistant 

 wrap or cathodic protection. It is customary to provide a free water supply to the slip 

 renters; hence, only one water meter is normally required for the marina. Ancillary facilities 

 may be metered separately. 



An electric power outlet is normally provided at each slip for boats over 20 feet in 

 length, with breaker switches at each outlet rather than just at the pier landing. Capacities 

 will vary from 20 to 50 amperes, depending on the amount of electrical gear carried by the 

 various berthed craft. Most craft require 120-volt service, but many larger cruisers also need 

 240-volt service. In a few installations, service is provided to the docks by overhead wiring 

 (Fig. 103), but a below-deck-level conduit is preferred. Special outside outlets are available 

 that are virtually foolproof and completely weathertight. Some are placed in riser racks just 

 above deck level (Fig. 104). Others are supported on locker boxes or other convenient deck 

 facility. Local agencies sometimes specify that only twist locks be used, but the outlet 

 selected should be of a noncorrosive outdoor-type, and well protected from the elements 

 (Fig. 105). It is important that outlets be located and oriented for convenient plug-in. Some 

 outlet boxes have been manufactured with such a penchant for weatherproofing that the 

 outlet plugs are difficult to reach and have become a source of irritation to harbor patrons. 



Calculation of distribution circuits should always be done by a qualified electrical 

 engineer to avoid inadequate sizing of Unes. A 25 to 50 percent demand factor may be 

 applied on each pier in estimating the connected load, but judgment must be based on local 

 experience. Conduits should be large enough for wiring to be pulled without difficulty. 

 Electrical conduits are often placed alongside the waterUnes and telephone or public address 

 system conduits. Grounding wires should always be returned to land and not to grounding 

 plates in the water. 



The electrical system for any large marina should be designed by an electrical engineer, 

 but for the small operator who may desire to design and install his own facilities, the 

 following data will be helpful. Where required, an owner's construction permit can be 

 obtained from a local inspection authority. A copy of the local electrical codes should also 

 be obtained. 



Service voltage to the utility outlets may be a 120-volt, 60-hertz, 2-wire system or a 

 120/ 240-volt, 3-wire system with the neutral (white or green) wire grounded for craft 

 requiring 240 volts. 



The measure of power is termed watts. The information on watts is obtained from 

 equipment nameplate data or may be computed if the values for amperes and volts are 



161 



