916 HYDROGRAPHIC MANUAL PaGE 840 



Give velocity, direction, duration, and the relation of time of slack current to that of high or low 

 water. Note directions of currents with reference to axes of channels and openings through bridges 

 and at other contractions of the fairway, across bars, in entrances, and in approaching docks and 

 piers. Also note the occurrence of rips, swirls, and eddies, and the effect of wind and freshets on 

 currents, and if flood or ebb current is ever entirely overcome. Describe fully all abnormalties in 

 currents or marked variations from usual phenomena. The notes should cover the entire area, both 

 inshore and offshore, and include all horizontal movements of surface waters, whether tidal, nontidal, 

 or both. Where the currents are due to winds or other meteorologic cause, or are greatly modified 

 in velocity, direction, and duration thereby, the variations produced should be determined and, if 

 possible, their relation to the conditions that produce them given — for example, the relationship 

 between the velocity and direction of the wind and the velocity of the current. 



A general discussion of the wind currents on both Coasts is given in Chapter 1 of the Pilot, which 

 is standardized. Local wind currents may be described in the text under local headings. A dis- 

 cussion of offshore currents and general coastwise currents in the area covered by the Pilot should be 

 included in Chapter 2. 



All current velocities should be expressed in knots. 



TIDE RIPS. — Give location and limits, and conditions of tide, wind, and sea which cause them 

 or make them worse. Give warning if they are dangerous under certain conditions and define these 

 conditions. If it is possible to avoid them, describe how to do so. 



TIME SIGNALS. — These are described in sufficient detail in Chapter 1 of the Pilot. Any 

 places displaying visual time signals should be noted in the text. 



TRUCKS. — If there is no railroad siding on the wharf, state if trucks can be used. Give facili- 

 ties for handling freight, and whether it is hauled by truck to and from port. If fuel can be delivered 

 by oil truck and put on board vessels, give quantity available, and rate of bunkering. 



TRUE COURSES AND BEARINGS.— Only true courses and bearings are to be given. (See 

 Bearings and courses.) 



TOWBOATS AND WRECKING EQUIPMENT.— State whether towboats are available and 

 if they are used for docking or mooring vessels. In the text and in Chapter 2 of the Pilot under a 

 paragraph headed "Towboats and W'recking Equipment," so that both items will be indexed, give 

 the ports at which towboats and wrecking equipment are available, including such items as horse- 

 power of towboats and the kind of wrecking equipment available at the different places. If this 

 equipment is available at a number of ports in the region, it may be tabulated in the appendix, with 

 references in Chapter 2 and in the text. 



TWO-WAY COURSES.— In areas where traffic is congested, it may be desirable to recommend 

 two routes in the Directions, one for entering, and one for leaving. Part of the Directions for New 

 York and for Boston are now in this form. Before recommending two-way courses for other places, 

 study carefully the information available, and obtain the approval of higher authority. 



UNCERTAINTIES. — ^ Where there is uncertainty regarding the correctness of statements ob- 

 tained in interviews, they should be forwarded to the Office with an explanation and an estimate of 

 their value. If considered worth while by the Office, such information may be entered in the Pilot 

 as a report rather than as a fact. 



WATER.- — Give the following information on this subject: whether it is suitable for boiler use, 

 and for drinking; piped to wharves and floats, or delivered by water boats; quantity available. Give 

 the maximum rate at which water can be delivered to vessels. Give the upstream limit of salt water 

 at different seasons or under various conditions. State whether overboard water is sufficiently fresh 

 for drinking or for boilers and if it is used for these purposes. 



WEATHER. — Obtain information in the field on any local peculiarities of weather that may be 

 important, and include in Pilot if worth while. 



Chapter 2 should contain a description of the weather and weather abnormalities which may be 

 found in the region covered by the Coast Pilot. 



WHARVES. — The depths at different wharves in the principal ports are given in the U. S. 

 Corps of Engineers Port Series. The accommodations at such ports must be mentioned in the 

 Pilot, but the descriptions can be more generalized if they are described in the Port Series. In 

 any case, the maximum draft that can be accommodated at a port, and the depths at those wharves 

 and floats used by the public must be given. Detailed information of this kind that is readily 

 available elsewhere should not be included in the Pilot. 



Descriptions of the wharves at many small ports, and the depths alongside, are published only 

 in the Pilot. It is important to get such depths, reduce them to the sounding datum, and publish 



