HUMA Maritime archaeology Gotland
Field work at Brusviken (week 32-34, 2008)
On the first day of field work in Brusviken an introductory meeting was held at the cabin, where the volunteers worked, ate and slept when not diving. Many different nationalities were represented in the project group (Swedish, Greek, Irish, Dutch, German and Danish), so the project language was quickly agreed to be English.
Project leader Göran Ankarlilja is presenting an example of documentation of an excavation square from the July-excavations at Krusmyntagården (just outside the windows).
The database for registering artefacts is being demonstrated for the new volunteers. The database contains information (description, dimensions, material, location, etc.) on all artefacts recovered during the excavations.
A lot of compressed air is needed for the dive cylinders, when many divers are working underwater throughout the day. A large portable Bauer compressor was used on site to keep up with the divers’ air consumption.
The dive gear was carefully assembled prior to each dive. The mask on this particular dive set is a full face mask, which covers the divers face completely.
Many of the volunteers were students of archaeology joining the project to gain experience with underwater field work.
During the field work at Brusviken two small boats were used for support and safety. One boat was primarily stationed in the area, where the divers were working, while the other was stationed on shore.
To ensure further safety an observer with radio contact to the boat and a suited diver was always stationed on the shore. All volunteers were briefed on emergency procedures. An oxy-box was available on site as well, so oxygen could be administered in case a diving accident should happen.
Archaeological diving often demands the diver to bring a lot of equipment for searching and documentation. Johan is here carrying an underwater metal detector and a writing slate besides his regular diving equipment.
All diving at the Brusviken site was shore based. The water is only knee deep for the first 50-70 m out from shore, where the limestone drops to 2-3 meters over a very short distance. These circumstances cause some interesting challenges in relation to entering the water for diving.
The limestone seabed is very slippery and the divers must take great caution when walking through the shallow waters. Even on days with no wind break water appears at the edge of the shallow waters
Passing through the break water to reach the dive site was sometimes a bit of a challenge. As the days of field work passed each diver developed their own personal technique for putting on fins and passing through the break water.
A diver puts out the measuring tape on the stern wood assemblage to be documented. The baseline towards which everything is measured can be seen in the right side of the picture.
A second measuring tape is placed perpendicular to the first measuring tape. The distance from both measuring tapes to the points to be documented are noted and drawn onto the drawing board.
The documentation process is slow. The first thing drawn is the outline of the wreck piece and the individual timbers. Later the details (tree nails, iron nails, cracks, tool marks and other features) are added.
The divers quickly settled into a documentation routine, where one diver handled the folding ruler and the other diver transferred the measurements carefully onto the drawing board. At the beginning of each dive control measurements were taken to cross check that the position of the measuring tapes was according to the drawing.
During underwater documentation the diver must carefully keep track of all tools. Note the ‘pencil on a leash’ in the front of the picture.
The water depth at the Brusviken dive site was maximum 7,5 meters and the water temperature a comfortable 15-20 oC. The length of the dives was therefore more controlled by air consumption, rather than by dive tables or feeling cold.