Page 281 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed

260 Maritime Archaeology: A Technical Handbook, Second Edition
Figure 9.15 Small prop-wash mounted on outboard motor to clear overburden. (Courtesy of Catherina Ingleman-Sundberg, Department of Maritime Archaeology, Western Australian Maritime Museum.)
powerful the thrust, the greater depth at which it can work effectively and the bigger the hole that can be dug. Used carefully, the prop-wash can be a reasonably useful tool, but used carelessly, it can cause untold damage. It is best used where large quantities of sterile overburden need to be removed, otherwise it is not a good excavation tool because it cannot be properly controlled. Small prop-wash systems mounted on outboard motors have been used for shallow-water work, but the systems are not particularly effi- cient (Figure 9.15).
VI. RECORDING
On an archaeological site one of the most important issues is recording information and then bringing this information to the surface and it is often surprising at what little thought goes into this process. Quite often notes are scribbled onto tiny slates that are used over and over again. These notes, on arrival at the surface, are transcribed into filed notebooks and the data then removed prior to the next dive. If a transcription error has occurred there is no opportunity to check it against the original data. A better solu- tion is to have large slates (A3 is ideal) with removable sheets of Mylar or some other waterproof writing film. This then provides a large working surface to record information and make sketches, and at the end of the dive the sheet can be removed, washed in fresh water, and immediately filed.