Digging square holes underwater (in low visibility) can get a little ridiculous – it is, however, achievable. To simplify the process, we used an excavation frame built by Jim Dunbar. The design is ingeniously simple. The frame is a two meter by three meter metal grid that can be raised or lowered on poles. Divers used rhino rulers to take depth measurements from the frame. To keep the ruler aligned, we duct-taped a meter long level to it. To keep it from floating off, we zip-tied on weights. The frame was equipped with sliding steel crossbar that could be moved around to take measurements in the middle of the unit. It spent quite a lot of time falling on my head while I was concentrating on digging square holes with straight sides and flat floors.
Troweling back the floor - 2011 © Douglas Inglis
The frame has other practical benefits as well. It is a perfect place to rest the dredge. You can tie your equipment to it. You can stand on it if you have to pound a core deeper. It is very large, and therefore easy to find if you get lost in a cloud of sediment. Its a good place to clip your fins. You can use it to excavate upside down. You can hang on it in high current. In essence, it is an underwater jungle gym for archaeologists. Measuring is almost secondary function.
Working within the excavation frame - 2011 © Douglas Inglis
Diving | Archaeology 
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