Page 111 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed

90 Maritime Archaeology: A Technical Handbook, Second Edition
dive the record sheets with the date, diver, and time logged on it, together with the survey data, can be removed from the slate and stored in a ringed binder. All measurements should be made using the same conventions and with tape measures corresponding to these units. It is usually best to work in ISO units of millimeters, meters, and kilometers. Thus all site recordings should be in 000.000 units (i.e., meters and millimeters). For obvious reasons, the tape measures should be chosen with millimeter graduations. A survey book should also be kept so that all data can be recorded from the sheets as soon as possible after the measurements are taken, or, alter- natively, these data stored on a computer. Again, documentation is of the essence in all underwater archaeological work. It is very easy to lose data simply because it is not properly documented. Although a diver’s writing slate is a very useful tool, unless the data are regularly and systematically transferred to some other system, they will inevitably get lost. With the diving slate, these important data can be recorded on the removable sheets and the reverse side used for a scribble pad where nonessential communi- cation between divers can be written down and later erased. The use of Mylar or some form of semimatte plastic drawing film is strongly recom- mended, particularly film that can be used in a photocopier or printer, where prepared or predrawn plans can be produced either for the project, individual dive, or project.
In many cases there will be only vague traces of the site visible on the seabed during a predisturbance survey, thus the initial survey may be rela- tively cursory. However, it may be possible to extend a survey below the surface of the seabed using a simple probe or more complex remote sensing techniques, thus obtaining additional information about the extent of the buried remains. These issues are discussed in the next section. In the case of a site that is highly complex but confined to a single area, photography will usually be the most effective method to record the site, provided there is good visibility. Again this is discussed in Chapter 6.
In other circumstances, where a site is comprised of a number of discrete areas of interest separated by considerable distances (i.e., separated by dis- tances that are several diameters from the area of interest), it would be wasteful to produce a photomosaic or a detailed survey of large areas of nothing. Therefore, it is important to record the areas of interest in detail and relate these areas to each other. A good example of such a site would be an anchor graveyard. The areas between the anchors are of no particu- lar interest, except perhaps for the broad topographical features. The anchors have to be recorded in detail and their orientation with each other determined. This type of site requires that a broad area survey be carried out to define the areas of interest, and additionally some point on each indi- vidual area of interest needs to be defined.