Page 268 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed

Chapter 9: Excavation 247
Figure 9.8 Telephone booth on the Tektash Brunu site, Turkey, at a depth of 40 m. (Cour- tesy of Jeremy Green, Department of Maritime Archaeology, Western Australian Maritime Museum and the Institute of Nautical Archaeology, Bodrum, Turkey.)
health and safety considerations. If the full face mask is used with scuba then through-water communications are possible (Buddy Phone, for example). This system works remarkably well, but allows only “simplex” voice transmission (i.e., either the diver is talking or topside is talking). If the system is surface supplied air (SSBA), then communications can be hard-wired in the umbilical and both the diver and the operator can talk at the same time. Being able to communicate with a partner or with the surface is a huge advantage, not only for improving the efficiency of the operation but also for training and safety. With this sort of arrangement it is possible to avoid some of the logistical problems that would occur when operating successive diving teams as previously described. The main disadvantage of the system is that it is generally expensive.
V. MACHINERY
A. WORK PLATFORMS
All sorts of different working platforms can be used, depending on the nature of the work and on factors such as on the type of site, budget, size