Excavation Planning and Logistics: The HMS Swift Project
Abstract and Keywords
For research projects, it is important to understand the relationship between the aims of the project and the resources available to complete the project. The HMS Swift project is a project that involves excavation, finds handling, conservation, and protection of the excavated areas. This article describes the preparation and procedure of excavation projects, the equipment used in excavation, technique, and safety considerations. A recovery operation depends on the size and number of the artifacts recovered. On completion of the excavation of a particular area or at the end of each field season, the exposed area is covered, but the method varies depending on whether the area has been finished or further excavation is planned. The complete archaeological collection is held in the museum's conservation and storage facilities. The local population plays an active role in the site's protection; therefore the archaeological site is not threatened by looting.
While maritime archaeology projects differ in character, their organization and planning share many components. Common to all projects should be a clear set of aims and objectives laid out within a project or research design, the scope of which is outlined in Rule 9 in the Annex to the UNESCO Convention on the Protection of Underwater Cultural Heritage (2001). Adequate planning and the provision of appropriate logistical support should aim to ensure that the project is carried out safely, completed according to a predetermined timetable, and within budget.
To illustrate these components this chapter will outline the planning and logistical support required for the excavation of sloop of war HMS Swift (1770) and, where relevant, make additional general comments regarding excavation planning and logistics. It is our intention that those involved in, or considering planning, their own projects, large or small, will use the factors outlined below as a reference and be able to more effectively develop their project plan.
(p. 134) Historical Background
HMS Swift left Port Egmont on the Falkland/Malvinas Islands in early March 1770, following Admiralty Orders (ADM 1/5304:3) to carry out surveys of the islands and coast in the region. Shortly into the mission, gale-force winds (ADM1/5304; Gower 1803) drove the vessel close to the Patagonian coast. Seeking shelter, the Swift headed for the estuary of Port Desire (now Puerto Deseado), a harbor already known to some of the crew. Close to the entrance of the ria (estuary) she ran aground, but was soon refloated. Court martial accounts are unclear as to what extent damage was sustained during this first incident. Out of control, the ship drifted farther up the estuary and grounded again on an unchartered rock covered by the high tide. This second stranding resulted in the total loss of the vessel, and three of the ship’s complement perished—two private marines and the cook. Facing a desperate situation, with few supplies, the ship’s master and six seamen rowed in an open boat over 480 km (300 miles) back to the islands to seek help. A month later, all of the remaining members of the crew were rescued by HMS Favourite, also based on the islands at the time (see Elkin in this volume).
The wreck lay undisturbed until 1982, when it was discovered by a local group of young, enthusiastic scuba divers. The seed of the idea for their search was sewn by Patrick Gower, a descendent of Erasmus Gower, first lieutenant of the HMS Swift. Gower had visited Puerto Deseado in 1975, bringing along his predecessor’s diary, which accurately described the loss of the vessel, but much to his surprise he found that nobody in the town was aware of the loss, much less knew where the wreck was located. The discovery of Swift subsequently acted as a catalyst for the early development of maritime archaeology in Argentina and continues to be one of the most important underwater archaeological projects in the country.
Artifacts were recovered by the local divers, who were then followed by the Underwater Archeology Working Group (GTPS), although these groups did not include a trained archaeologist. GTPS was created (Libonatti 1986) following a series of seminars on underwater archaeology between 1983 and 1985 organized by ICOMOS (International Committee on Monuments and Sites). One of the group’s aims was to experiment with underwater archaeological techniques on several sites, including Swift. Between 1987 and 1989 the GTPS/ICOMOS group carried out four field seasons, during which approximately 80 objects were recovered (Elkin 2002).
(p. 135) Current Research
In 1997 an interdisciplinary team, Programa de Arqueología Subacuática (PROAS) of the National Institute of Anthropology (INAPL), Buenos Aires, Argentina, was commissioned by the provincial government of Santa Cruz to develop research aims for a new stage of work. For the first time, the investigating team included a trained archaeologist and specialists in naval architecture and marine biology. Under this new direction, a number of research themes were developed (Elkin 1997). These included the examination of: (1) the role of the ship within the geopolitical context of the South Atlantic at that time (Dellino-Musgrave 2007); (2) the ship’s design, construction, and subsequent alterations; (3) the social hierarchy and other aspects of life on board as reflected by the material culture; (4) evidence of technological change that characterized the eighteenth century; and (5) site formation processes (Elkin et al. 2007). A further theme has been added to take account of the unexpected discovery of the skeletal remains of one of the two private marines lost with the ship, which were discovered in 2005 and subsequently recovered in 2006 (Barrientos et al. 2007).
The main considerations, aside from the specific archaeological aims, objectives, methodologies, and artifact conservation, include safety, accommodation, transport (air, land, and water), size, composition, and experience of the team, equipment requirements and maintenance (diving and archaeological), and funding, as well as other things that sometimes may not seem so obvious, such as allowing time for media and local public events, which can have significant benefits in promoting community involvement, goodwill, and support for the project.
One of the fundamental issues in the planning of all of PROAS’s projects is taking into account the significant distances between Buenos Aires and other parts of the country. Puerto Deseado is situated over 2,090 km (1,300 miles) south of Buenos Aires. The planning of an underwater excavation is further complicated by the specialized nature of the diving and excavation equipment, which requires support that is not readily available in most coastal locations. Should equipment break down or be left behind, the solution is unlikely to be a visit to the local dive or hardware store to find a replacement. The nearest dive store stocking anything beyond the basics is over 483 km (300 miles) north, in Puerto Madryn, one of the main centers of recreational diving in Argentina, or alternatively Rio Gallegos, which is almost 724 km (450 miles) to the south.
Aside from the lack of specialized equipment, locally the sourcing of even more mundane materials can be a problem, and such materials are likely to be more (p. 136) expensive. Due to this factor, virtually everything required for the project, as well as replacement gear, is sourced in Buenos Aires and transported south. Consequently, the transportation of project personnel, as well as the heavy and bulky equipment necessary to carry out even a small excavation field season, becomes an issue, particularly when the project budget is relatively constrained.
An important factor in the continuity of the project is maintaining relationships with the three levels of Argentine administration (federal, provincial, and municipal), each of which has a role in enabling the project. All are involved to some extent with providing permissions, funding, or administrative support in one form or another. It is essential that all necessary permits are received well in advance of the beginning of the fieldwork. This whole process involves a significant amount of time. Aside from the official process, it is also important to coordinate the timing of the project with the director of the Brozoski Museum, the local base of operations. The museum provides space for administration, the high-pressure diving air compressor, and changing and drying facilities. An open area at the rear of the museum is used for the cleaning of dive equipment.
Since PROAS’s involvement in 1997, fieldwork has been intermittent, partly due to the sporadic nature of funding, but also to prevent the limited conservation capability and storage area from becoming inundated with finds. Several field campaigns have been devoted to hull surveys and environmental monitoring rather than to excavation.
Most of the funding for the project comes from government sources. The Ministry of Science and Technology and the Ministry of Culture cover staff salaries, the municipal administration of Puerto Deseado contributes to the costs of accommodation and consumables such as fuel, and there is a considerable gift-in-kind contribution made by the local community. In 2008, PROAS received a grant covering two field campaigns from Argentina’s National Research Council and also a project grant from the National Geographic Society, with some additional support from the British Embassy. Valuable nonmonetary support is provided locally, such as a berth in the harbor for the project boat, towage, loan of equipment, and occasional emergency repairs of equipment.
The estimated budget for a typical three-week field season, excluding salaries, flights, and additional local transportation, is US$12,000. This sum covers, accommodation, and food, honorariums for the nonstaff members of the team, routine preproject equipment-servicing costs, spares for and replacement of diving and archaeological equipment, consumables such as fuel for the boat and water pump, freight of equipment, transfers to and from the airport to Puerto Deseado, local (p. 137) repairs, incidentals, and so on. The cost of the postseason report, written by the salaried members, is absorbed in staff time, with much of the scientific analysis done in collaborative exchanges with academic institutions, at minimal cost. The municipality is responsible for the costs of the storage and conservation of the recovered artifacts. An estimate of these considerable costs would normally need to be factored into the project budget. A realistic estimate of them is somewhat dependent on an assessment of the type and quantity of artifacts that could be found during the excavation. This is not always easy, but it can be attempted based on the known physical characteristics of the site and to what extent salvage or other human or environmental factors have resulted in the loss of archaeological material. Comparison with the recovered material on sites in relatively similar environmental conditions will also provide a guide to expected discoveries and related conservation budgets. Relative to the Swift, the upstanding hull is evidence that the environmental conditions are conducive to preservation, combined with the knowledge that there has been relatively little human impact on the site since the sinking and that previously recovered finds are normally in good condition—indicators that new finds can be expected in a range of categories, including organics, glassware, ceramics, and mainly nonferrous metal objects. Although a definitive figure is not available for the costs of conservation and curation, based on most excavations, the figure will match and likely significantly exceed the costs of the fieldwork. The provision of adequate conservation and storage facilities will therefore define the limits of the archaeological aims and objectives. Recognizing the level of the museum’s resources, the Swift’s archaeological excavation objectives are therefore limited to small concise areas aimed at answering specific research objectives outlined above. Failure to take this important factor into account will almost certainly lead to excavated material languishing in storage, unconserved, for longer than is justifiable.
Accommodations and Catering
An important but sometimes underestimated component in the organization of field projects is the matter of where the team will rest, eat, and sleep, not to mention where archaeological logs, diaries, and so on will be completed. The phrase “An army marches on its stomach” can equally be applied to archaeological projects, particularly those where temperatures and conditions are unduly cold. A typical day in the field, especially when diving in cold conditions, is quite long and arduous. It is therefore essential that the team is adequately fed and accommodated. Although to camp is an option that should not be discounted and may in some cases be the only option, in less than ideal conditions, the team’s performance will be affected as time passes. It has to be borne in mind that factors affecting the participants’ physical well-being will gradually have an impact on daily performance and even exacerbate the possibility of accident. Archaeological standards may also suffer.
(p. 138) Transportation
The prime objectives of transportation are to get all equipment and personnel to the project location on schedule and, once on site, to be able to access the site, either from the shore or by water transport. With regard to this specific project, there are several components: moving the archaeological team and equipment to and from Buenos Aires; local transportation from the Brozoski Museum to the port’s maintenance facility; and the water transport to the diving platform. For reasons of operational convenience as well as to reduce the freighting costs of equipment, the larger and heavier components, such as the diving cylinders, the diving weights, the inflatable boat, the outboard engine, the high-pressure air compressor used to charge the diving cylinders, and the excavation equipment, remain in Puerto Deseado between field seasons. Should the need arise to run a project elsewhere, additional diving equipment can be sourced in Buenos Aires or Puerto Madryn, the main diving centers. Only personal diving equipment and that which requires maintenance is routinely brought back to Buenos Aires.
Despite this arrangement, a significant amount of diving and archaeological equipment, as well as supplies and personal items, need to be transported. Until recently, airlines have been sympathetic to requests for the carriage of project equipment that exceeds the normal baggage allowance, but recently normal baggage limits are much more strictly enforced. Most of the remaining diving equipment and archaeological materials is sent by road transport from Buenos Aires to Puerto Deseado, which takes two days. On arrival, the shipment is stored in the Brozoski Museum.
Personnel fly to the closest domestic airport, Comodoro Rivadavia, 290 km (180 miles) north of Deseado, with the final leg of the journey being completed by road. Consequently, most of the first day is lost in traveling.
Locally, the team is dependent on the Prefectura (coast guard) for the transportation of personnel and equipment from the museum to the harbor, with the project’s own boat being used as a ferry from the berth to the dive platform, a routine that is carried out daily.
The Wreck Site of HMS Swift
The wreck site, located at Lat. 47° 45′ 12″ S / Long. 65° 54′ 57″ W (Figure 6.1), is approximately 45 m (148 ft) offshore of the commercial port facilities, adjacent to the rock on which the ship foundered, now somewhat closer to shore than in 1770 due to recent land reclamation. It lies between the end of the commercial quay and the port’s maintenance facility. To the south side of the site is a secondary channel that leads out to the ria and from there on to the open sea.
(p. 139) The location has a number of important advantages over more exposed or remote coastal locations: a smaller/simpler platform suffices; minimal transfer time from berth to site is needed; relatively sheltered water reduces the number of days lost to bad weather; and importantly, in the event of an accident, medical services are relatively close.
The wreck of HMS Swift lies on an 8° slope, heeled over to port at an angle of 58° (Elkin et al. 2007). Many of the starboard frames rise 2.75 m (9 ft) above the seabed, although the keel remains buried, as are the port frames (Figure 6.2). The main deck is broken in various places along the length of the ship, and most of what was originally above it, such as the masts, has either disappeared or is no longer in place. Despite the partial structural collapse, a diver can, even in low visibility, move from bow to stern following either the starboard side structure or the line of the main deck. Due to the position of the hull, many artifacts originally located on the starboard side, such as the main armament, now lie on the port side of the wreck. In addition, part of the capstan and two anchor stocks can also be seen, partially hidden or camouflaged under sediment and biofouling. Smaller artifacts of various materials, mainly glass, ceramic, various metals, stone, and wood, are sometimes found partially exposed. Artifacts determined to be at significant risk are recorded and recovered, with the remaining ones lying outside the excavation areas normally (p. 140) reburied and left in situ. Artifacts that have remained covered by the fine-grained silt have survived in remarkably good condition.
Site Characteristics and Their Impact on Diving Operations
Depth, visibility, temperature (underwater and surface), and tidal flow all affect the way in which the work is organized and the time required to achieve the project aims and objectives. However, while any or all of them, in combination, may be limiting factors, they should not be used as excuses for poor archaeological standards. Solutions can be found to most problems. It just may take longer and cost more to achieve acceptable results. Although the site is in relatively shallow water, it is cold and dark, and unpredictable strong currents that can result in diver disorientation often sweep through the three-dimensional structure. Additional complicating factors are boat traffic that is sometimes close to the site; marine animals; and environmental factors, such as the kelps, that may affect how diving is conducted.
The bow lies in 10 m (33 ft) at mean spring tide, with the stern in no more than 18 m (60 ft) (Elkin et al. 2007). The seabed continues to gradually slope away from the stern toward the open area of the ria and is characterized by the dominance of fine-fraction sediments ranging from clay to fine sands overlying a pebble bottom. Although the depth of the wreck site makes it ideal for the use of enriched air (nitrox), it is not commonly available in Argentina.
Poor underwater visibility can seriously limit the achievement of good archaeological results. On the site of the Swift, visibility ranges from an almost lack of visibility during or after storms, as heavy rains wash sediments off the land, to dark but relatively clear 4 m (13 ft) water during neap tides combined with periods of calm dry (p. 141) weather. The average visibility is around 1 m (3 ft 3 in). Light levels vary significantly depending on the depth, surface light, and sea conditions. There are numerous artificial lighting solutions, whether handheld or head-mounted, or more sophisticated solutions, such as using surface-powered floodlights. Handheld torches and video lamps are used on the project; in addition, a strobe light is placed on the access point to the excavation zone to help divers find their way. Although they are not always used on the site, strobe lights or light sticks attached to divers’ equipment can also help them to maintain contact with their buddies in poor conditions.
Water and Surface Temperatures
A cold diver is less efficient than a warm one and is also potentially less able to deal with an incident, so it is important to use appropriate equipment to keep divers reasonably comfortable for the full duration of a dive. Seawater temperatures during the Patagonian summer (21 December to 21 March) vary between 8° and 13° Celsius (46° –55° Fahrenheit), with winter temperatures reaching a low of 4° C (39° F), although no diving on the site is actually carried out during this period. As underwater excavators are likely to remain quite still for relatively long periods during a dive, they tend not to generate much heat and therefore will tend to get cold more quickly. Dry suits are the norm, although some of the region’s archaeological divers choose to use wet suits made from 4/10 inch (10 mm) smooth-skin neoprene. These wet suits provide sufficient insulation from cold, are much less expensive, and are easier to repair, a factor to be taken into consideration in more remote locations.
Air temperatures during the same period range between 6.5° and 23° C (44°–73° F), but can change dramatically within these extremes. Higher surface temperatures can also cause a fully kitted diver waiting to dive to become very uncomfortable, potentially even hyperthermic, so it is important to coordinate dive times and handovers to reduce this possibility. Maintaining adequate supplies of fresh water will help avoid dehydration.
A tidal amplitude of 4 m (13 ft) during mean spring tides generates strong tidal currents that can reach 2 knots on the site and are even stronger in the ria. The strongest currents tend to flow on the ebb tide, sweeping the wreck from bow to stern. The timing of the dive periods is also variable due to the natural topography and harbor construction in and around the area. This factor often leads to the need to arrive on site early and wait until diving conditions improve. Depending on the time within the lunar tidal cycle, a diving window of around 4–6 hours coinciding with the beginning of the ebb tide usually provides the best visibility. This tidal window is the main factor that governs the start time for each diving day.
Although there is some natural shelter from the currents provided by the ship’s structure, this is not the case when entering or leaving the site. To help divers, there is a line from the diving platform (a small pontoon described below) to the excavation zone. The down-line from the pontoon is attached to a seabed sinker marked (p. 142) with a strobe light placed a few meters outside the structure (to avoid damage to the site), and from there a ground line runs to the grid.
The ria is a natural habitat for many species of fauna, including shark (Heptranchias sp., Galeorhinus galeus, and Scyliorhinus canicula) and the Southern sea lion (Otaria flavescens). Although sharks have not been seen on the site, sea lions are a regular visitor. While seemingly not posing a direct threat to the diver, they are inquisitive and can become excited in their desire to “play,” to the point that on some occasions it is impossible to continue to work, at which point dives have to be terminated. The possibility of such events becomes part of the project planning.
In addition, planning needs to account for the large loose kelps (Macrocystis pyrifera), often more than 6 m (20 ft) in length, with holdfasts up to 1 m (3 ft 3 in) in diameter. They drift down the ria and accumulate around the site and the pontoon. They are remarkably durable and in the very poor underwater conditions pose a potential entrapment hazard for the diver. On the surface, they accumulate around the diving platform, and if not regularly removed they would significantly increase the drag on the pontoon’s mooring, raising the risk of a mooring line failure.
A major component in the planning and ultimate success of any underwater archaeological project, particularly an excavation, is the experience of the team. It is essential that the team as a whole is qualified and competent to carry out the full range of project tasks. Aside from the archaeological tasks, provision should also be made for those tasks that are similar to those often found in a commercial context, such as the laying or moving of moorings, the lifting or moving heavier artifacts (such as cannon or anchors), the construction of grids, etc., all of which become more difficult in poor underwater conditions. If these tasks are anticipated, either the archaeological team will need experience or training in doing them, or additional team members will be necessary.
PROAS’s archaeological field team normally consists of six diving members at any one time: three staff members from the Institute of Anthropology in Buenos Aires, plus other archaeologists who, although they are not part of the Institute’s staff, routinely take part in PROAS’s projects. Many of the team members have been involved with the project for over 10 years. This level of experience on the site is a major (p. 143) factor in the planning of individual dives and in the subsequent archaeological interpretation of results.
Colleagues from other Latin American countries also occasionally take part in the project, which forms part of an informal initiative to provide project experience and help maintain and develop field skills across the region. There are also several overseas archaeologists associated with the project who provide expertise on specific issues, such as physical site protection methods, and long-term site protection should further port development pose a threat to the site’s integrity.
Although the project should not be considered a training project, a number of archaeology students have also had the opportunity to take part. They are permitted to excavate only under the direct supervision of one of the more experienced team members, an important consideration in ensuring that excavation standards are maintained to the highest possible level.
The archaeological team is also accompanied by a documentary filmmaker, who has been recording the progress of the project for the past three years. Occasionally one or two local divers help with nonarchaeological tasks, such as being a dive buddy to one of the archaeological team during routine dives, helping with the backfilling process at the end of the field season, and assisting with mooring operations associated with the diving platform (discussed below).
Diving Qualifications and Experience
Following a review of Argentina’s diving regulations, a professional “scientific diver” qualification has been introduced, the criteria for which have been developed in association with PROAS and other Argentine scientific groups (Prefectura Naval Argentina 2008). This qualification will in effect supersede the variety of amateur and other professional diving qualifications currently held by team members. Along with the new scientific diver regulations, a more stringent and regular medical requirement has been introduced, in line with the domestic commercial diver requirements and the practices of other countries. It is also important to ensure that personal insurance for all team members covers personal accidents, including recompression treatments and possible air transfers to the decompression chamber, and that there is third-party insurance to cover accidents involving other members of the team and the public.
Prior to arrival in Puerto Deseado, the Prefectura (coast guard), the competent authority for the administration of safety matters and policing of Argentina’s coastal zone, must receive notification of the intended diving operations, including a list of all project diving members and an outline of the planned field campaign—dates, times, and so forth—but excluding archaeological details. On arrival in Puerto Deseado, diving credentials are registered and approved by the authority. Only after this step can diving begin.
In planning the diving operations and selecting the team it is important to understand that the level of archaeological and diving experience required on one site will not automatically be the same as that on another. The level of experience (p. 144) required will vary depending on the site characteristics and the tasks scheduled to be carried out. Also, possession of what appears to be an appropriate level of diving qualification and requisite numbers of dives logged should be viewed only as indicators of competence, not as a guarantee. Those responsible for safety (see below) should not take anything for granted. An assessment of each team member’s experience should include the number of dives in similar environments, how recently they were done, experience in the range of intended tasks, and whether similar diving equipment was used. When there is any doubt about the competency or fitness of an individual, checkout dives and additional training should be considered.
Any additional skills training for anticipated new tasks should be completed before the project. It is also advisable to consider workup dives to try out new or repaired equipment, or to generally refresh skills (e.g., good buoyancy control). Avoiding contact with sensitive archaeological areas is no less important than avoiding landing on a coral reef; the only difference is that coral can potentially regenerate itself. It is therefore good practice to acquire and practice these skills prior to the project, rather than during it. Being completely at ease and in control are major factors in successfully completing any task.
Developing a Project Safety Policy
A safety policy that covers all aspects of the project, marine and terrestrial, must be an intrinsic part of all project designs. Over recent years, safety has become a major concern for anyone involved in running a project due to a marked change in attitudes, which have moved from an acceptance of personal responsibility to a desire to establish liability and obtain compensation. While acting as project safety officer has always been a heavy responsibility, this new culture makes it even more so and as such should not be accepted lightly.
Dive Safety Officer and Documentation
One of the primary tasks is to identify all hazards or risks associated with the project. Once the scope of the risks has been identified, actions should be taken to minimize the possibility of hazards affecting the project team, and procedures should be developed to be followed in the event on an incident, such as a casualty evacuation plan. It is important that a project member has responsibility for all safety-related matters, perhaps on a day-to-day basis, or even shared, as long as all concerned are competent to carry out the role. These fundamental principles should apply to all projects, large or small.
On larger projects, the roles of safety officer or dive supervisor should be separate from that of the archaeological director or principal investigator to ensure that (p. 145) conflicting interests do not interfere with the decision-making process and that the necessary attention is directed toward team safety. Consideration should also be given to creating a project-specific code of operations that everyone associated with the project is given, accepts, and ideally signs, confirming adherence. Even on a small project such as the excavation of Swift, it is essential that someone with the appropriate experience is responsible for dive supervision. The person responsible for safety has the ultimate say over all factors of the operation relating to safety of team members. On the Swift project the role of dive supervisor is shared, allowing everyone to dive; the responsibility for the supervision of individual dives is noted in the daily dive log. On a larger project it is good practice to keep a daily operational log that is complementary to, but separate from, the archaeological daily diary that records aspects relating to the diving operation. This record should include the date, site, names of the team and of visitors, name(s) and times of responsibility of the dive supervisor(s), time of arrival and departure from the site, time of the start and end of the dive operation, weather conditions, high- or low-water times, tidal amplitude, and any significant event occurring during the operation (HSE 1997). There should also be regular reassessment of the identified risks and daily equipment checks to ensure, as far as is possible, that all equipment is in good condition and is functioning properly. It is recommended that a written checklist be completed daily by a competent person and signed by the dive supervisor. On arrival in Puerto Deseado the local hospital is informed about the diving timetable and an emergency casualty evacuation plan is agreed on. Emergency telephone numbers and VHF radio channels are checked and noted on the dive safety log, including the contact number of the closest decompression chamber.
One potential but undesirable possibility is the influence of peer pressure: pressure on team members to dive, irrespective of diving conditions, competence, or personal well-being. New team members, perhaps wanting to demonstrate their value to the project, may be affected more than others by peer pressure. The situation can sometimes be difficult to recognize, so it must be made clear during safety briefings that no one is obliged to dive, that pressure will not be applied on anyone to do so, and that any dive must be aborted if the diver feels ill at ease. Everyone also has a responsibility not to ignore factors that may affect their diving fitness, such as seasickness, tiredness, anxiety, alcohol or substance abuse, illness, or injury. By ignoring such things, divers can potentially place themselves and others at risk. The dive safety officer must be prepared to intervene should there be good reason to doubt that someone is either fit to dive or competent to carry out a specific task.
Daily Safety Procedures
On board the diving platform there are first-aid and O2 kits, and VHF radios for routine and emergency communication with the Prefectura. In addition, team members have personal cellular phones. These represent an informal backup, but their performance in remote locations or far from shore should not be taken for (p. 146) granted. The Diving A flag is flown for the duration of the operation. Several members of the team also have first-aid and oxygen-administration training; there should always be someone on the diving platform able to render first aid. In addition to the diving cylinders routinely required for the day’s diving, extra cylinders are also available on the pontoon for emergency use. Before commencement and on completion of diving, the Prefectura is notified by radio with a prearranged call sign. They are responsible for notifying the team of any shipping movements that will necessitate the temporary cessation of diving and of imminent bad weather that would lead to the closure of the port, during which time all diving and shipping movements are restricted.
In the event of an accident, the Prefectura is responsible for the incident’s management and for coordinating the movement of a casualty from the diving platform to the hospital. This is a local arrangement and one that is not necessarily typical of all sites. It is crucial that procedures be established with the appropriate authorities before the operation commences and that they be periodically reviewed to ensure that the plan remains up-to-date and, where changes have been made, that relevant people have been informed. Although there is a small but well-equipped local hospital that can deal with accident and emergency injuries, the nearest hyperbaricchamber is in Puerto Madryn, a 966 km (600 mile) round trip for the rescue helicopter or light aircraft—if one is available, which, given Patagonia’s size, cannot always be guaranteed. Consequently, the daily diving regime has to be conservative and accident prevention paramount.
Excavating at HMS Swift
Preparing for Project Operations
As most of the bulkier project equipment remains in Puerto Deseado between field seasons, it cannot be prepared in advance of arrival on location. Therefore the predeparture preparations in Buenos Aires focus on repairing and servicing personal diving equipment; identifying and purchasing key spares, such as filters, compressor lubricants, torch batteries and chargers, O-rings, fin straps, and buckles; acquiring spares for the boat and motor; and organizing or purchasing archaeological paperwork, daily log sheets, measuring tapes, underwater drawing boards, pencils, erasers, finds and environmental sample containers, cameras, photographic scales, archaeological recording tools, calipers and additional items for samples, self-sealing finds bags, permanent markers, finds tags, and so on.
(p. 147) Once in Puerto Deseado, the team divides into two groups. One organizes and prepares the paperwork and associated archaeological materials, while the other prepares the boat, the outboard engine, the high-pressure compressor, and the water pump that powers the water dredge (detailed below). Individuals are responsible for the preparation of their personal equipment.
The inflatable boat is reassembled, the outboard motor’s fuel system is cleaned, ignition plugs are routinely replaced, moving parts are lubricated, and the necessary fuel is secured. The engine is briefly run before being attached to the boat transom. The water pump for the water dredge is stripped down, cleaned, and lubricated, and the spark plug is replaced. Before deployment on site, the components (dredge, hose, and water pump) are connected and tried out on the foreshore.
The diving air compressor is the heart of any diving operation; without it the project would come to an abrupt halt. To reduce the possibility of mechanical failure, the manufacturer’s servicing and operating recommendations are strictly followed, and only personnel familiar with its operation are allowed to operate it. If in the unlikely, but possible, event that a spare part is required, it may be necessary to import it, as few specialized parts are available in the country. This is not only expensive but also time-consuming, as imports are normally routed through Buenos Aires. As a fallback position there are other small-capacity compressors in the town, but the daily project requirement would place a heavy burden on them. For many mechanical parts it is customary to replicate them locally, but this pragmatic innovative solution does not extend to more sophisticated equipment, such as the compressor.
Before diving operations are under way, the team meets to discuss the specific archaeological aims of the day. Once agreed on, the tasks are scheduled into a preferred order, and dive pairings are decided. Depending on progress and diving conditions, the original plan may be amended, but there is a significant benefit in developing the plan in the relative comfort of the museum before the distractions of preparing diving equipment commence.
All diving is carried out in pairs using scuba equipment, comprising a single 100 ft3 (3,000 psi) capacity tank, a buoyancy compensator, and a regulator with an alternative air supply, plus the usual ancillaries. The U.S. Navy Standard Air Table is used as the basis of the diving, and all dives are recorded: times in and out, cylinder contents in and out, length of dive, and responsible supervisor are all noted on a daily dive log sheet. In the case of the HMS Swift site, only occasionally is there more than one pair of divers in the water, mainly due to the limitations of the size of the excavation area. However, should there be more than one area being excavated, or the need to do other tasks such as video or photographic recording or hull survey, and where the underwater conditions are suitable, it is sensible to utilize the available dive time and undertake tasks simultaneously. It is important that the separate diving pairs not get in each other’s way and that the appropriate levels of safety are planned.
(p. 148) During an average day, depending on the tidal window it is normal for the team to complete 10 or 12 dives (five or six diving pairs) per day. While the use of dive computers or dive timers is routine, they are only used as a backup to the agreed-upon procedure based on the dive tables and the instructions of the dive safety officer. Each pair carries out their first dive of usually between 45–55 minutes, depending on the depth of the area being excavated, with a surface interval of a minimum of 1.5 hours before doing a second, usually shorter, dive. Prior to all dives each diver carries out routine checks to ensure that the equipment is functioning properly (Figure 6.3).
All tasks require a level of concentration. Some, including excavation, can become totally absorbing, to the point that awareness of one’s surroundings diminishes. When underwater, this can have consequences that can place the excavator at increased risk. The main danger is that the diver may fail to regularly monitor dive times and dive tank contents. The consequences can be serious, including going beyond the planned dive time, incurring unplanned decompression, or perhaps even running out of air. Sharing air with a companion is an option, but as buddy pairs are on the same profile with the same equipment it is possible that they will run out of air more or less simultaneously. Given the strong tidal conditions, combined with harbor constructions, large moored vessels, and surface traffic, a free ascent to the surface is not a risk-free option. A secondary independent breathing supply would reduce this factor, but it is not a common practice in Latin America. Diver/surface/diver communications would enable a supervisor to monitor dive durations and remind the diver to check air contents, as well as to advise him or her when to stop work and surface. Archaeological instructions from an archaeological supervisor can also be provided, without interrupting the dive. However, this equipment remains on the team’s wish list.
(p. 149) Part of the daily routine is to take and remove all equipment except diving weight-belts from the diving platform. Although it would be more efficient to leave more equipment on the platform, the risk of losing it through bad weather, collision, or theft is considered too high. This daily routine continues for six days; the seventh day is a rest day.
The dive platform is a steel pontoon provided to the project at minimal cost by a local towage company; it allows for a working area of 5 m by 4 m (16 ft by 13 ft). A reasonably large boat would be required to create a similar working space, the potential charter of which would have a significant impact on the project’s overall budget. Although the platform lacks shelter or other conveniences, they are only a short boat ride away, so it is adequate for the needs of the project. It is held in position by four moorings strategically placed to enable it to be moved as close as possible to the excavation area. Two moorings would suffice, but four is preferred due to the lack of shelter from the strong winds and currents that can create rough sea conditions. Three of the moorings are cylindrical concrete blocks with metal rings cast into the concrete; the fourth, which forms the bow mooring point, is a metal strong point drilled and securely cemented to the rock adjacent to the site. Irrespective of the time between field seasons, it is important to inspect the moorings, shackles, and mooring ropes for any defect prior to securing the diving platform. It is also important not to cut corners with the mooring system, as the breakage of a single component will lead to a sudden repositioning, possibly causing excavation equipment to be dragged through the site, causing damage and potentially putting divers at risk. It also necessary, sometimes daily, to remove large quantities of kelp that accumulate around the moorings; the kelp makes access to the down-line more difficult and puts additional strain on the mooring components.
The main site marker buoy remains permanently in place, but those that normally mark the moorings are removed between field seasons. Their positions are known, but it still requires a dive to relocate and mark them. Once they are found, inspected, and moved if required, and their positions are buoyed, the pontoon is towed into position. The team’s small inflatable is inadequate for this purpose, so a local tug company provides the service free of charge, an example of the support the project receives from the local community. The only downside to this arrangement is that the timing of the operation is beyond the team’s control.
Preparation of the Excavation Area
The excavation areas are divided into 2 m by 2.m (6 ft 3 in by 6 ft 3 in) sections that conveniently fit between decks. The grid also provides a means of supporting the excavators above sensitive archaeological areas, but it should be noted that if the grid is (p. 150) used as a reference for surveying it may be disturbed by a diver involved in excavation, which will affect the accuracy levels of the measurements. The grid is made from stainless steel and has adjustable legs that enable it to be leveled over the excavation area.
Although the Swift project uses a water dredge, otherwise known as an induction dredge (Figures 6.4 and 6.5), it is also useful to consider the airlift (Figure 6.6), as together they are the tools most frequently used when excavating underwater archaeological sites. Ultimately, choosing which to use will depend on the site characteristics, the size of the diving platform, the experience and training of the excavators, and to some extent on a personal preference for one or other of the tools. Both utilize suction to carry away the spoil from the excavation area, but as their names imply, one is powered by air and the other by water; they also differ insofar as the water dredge lies horizontally when in use, whereas the airlift is almost vertical when being operated. They can both be constructed from plastic or metal, ideally lightweight for ease of setup on site, and the suggested diameter of the equipment for archaeological purposes is 10 cm (4 in), although larger diameters can be useful for quickly removing backfill. They can be purchased from specialist equipment suppliers or, alternatively, can be constructed from components found in home construction stores, but advisably using a proven design.
The Swift project’s single water dredge is powered by a relatively small 5-horsepower, 200-gallons-per-minute water pump, a decision based on the limitations of space on the project’s diving platform and the need for portability, but it should be noted that much larger pumps are available that can power numerous dredges when required. (p. 151)
(p. 152) The amount of suction depends mainly on the pump’s flow rate, but it is also affected by the pump’s head pressure, leakages through joints or small tears in the delivery hoses, the diameter and position of the dredge-jet, the diameter of the dredge, and the angle and length of exhaust pipe. The pump supplies water to the tool via a flexible hose connecting the pump and dredge; this can be either lay-flat hose, commonly used by firefighters, or a more inflexible tubular hose. Lay-flat hoses have the advantage of occupying less space in a small boat, but they tend to be more prone to damage than the more rigid alternative.
The 7.5 cm (3 in) diameter inlet/outlet pump used on the project produces enough suction for the single dredge to remove fine silt, sand, mud, broken shell, and light gravel along the horizontally positioned 4 m (13 ft) long discharge pipe that carries the spoil off the ship’s structure. Larger material such as pebbles and stones can gradually accumulate along the discharge pipe, particularly if it is quite long, eventually reducing or stopping the suction completely. The dredge-head has a coupling for the water supply hose, and an on/off valve, an important safety feature that is discussed below. At the rear of the dredge-head there is a compatible fitting for attaching the exhaust section, which can be in sections if necessary to facilitate easier transportation and storage. A flexible extension to the working end of the dredge is used to provide greater mobility around the excavation area, bearing in mind that the on/off water control valve should always be accessible to the excavator.
The airlift is also a simple device, consisting of a length of hollow pipe, typically about 2–3 m (6–10 ft) long (although it can be longer depending on water depth) and a 30 mm diameter (1.25 in) air supply hose that connects to a coupling on the airlift to the low-pressure air compressor located on the surface. Suction is created at the working end by the expanding air rising up the body after it enters the airlift. Even the lower-capacity compressors, more usually found powering tools on a construction site, will deliver approximately 190 cfm (5.38m3/min) of air between 102–175 psig (7–12 bars), which is sufficient power for two airlifts to be used simultaneously. The disadvantage is that the machine is quite large and heavy, needing rather more space on the diving platform than the small water pump used on the Swift project. The rate of airflow from the compressor is the main factor that determines power, but leakages through loose joints, excessive length, small tears or porosity in the delivery hoses, and greater water depth can also reduce the power.
Setting Up the Excavation Equipment
The water pump used on the Swift project is placed on the corner of the pontoon closest to the site to reduce the length of supply hose to the dredge on the seabed, to avoid unnecessarily increasing the water-drag on the hose. Normally, the hose spans (p. 153) about twice the water depth, but this depends on factors such as tidal amplitude, strength of current, and the distance from the platform to the excavation area. It is advisable to place the pump close to the water-level to reduce the head pressure, which will affect performance. The pump inlet draws water toward it, but in so doing it can suck in seaweed or other floating debris that can accumulate and block the pump inlet, resulting in a partial or sometimes total loss of suction. Although the water inlet itself is protected by a filter, placing the inlet in a secondary container such as a bucket can help protect the inlet and reduce this problem, but it is recommended that the inlet be periodically inspected and any material removed as necessary.
The dredge is placed and fixed adjacent to the excavation area, with the long exhaust or discharge pipe positioned horizontally and with the end outside the ship’s structure and ideally downstream to avoid fine material from drifting back over the excavator, which would reduce visibility. If the exhaust is inclined too high, heavier material will begin to accumulate inside and will eventually reduce suction, leading to a blockage. A dredge constructed from plastic materials can be more or less neutrally buoyant, so it may require securing to the seabed or site by weights or lines. It is also useful to place a small buoy or container tied toward the end of the exhaust, the contents adjusted so as to keep it level, or slightly declined to help material move away. This will keep the exhaust off the seabed and minimize the stirring up of loose sediment. Care has to be taken to keep the exhaust away from potentially sensitive archaeological material. Less-well-designed equipment may have an imbalance of pressure between the inlet and outlet of the dredge, causing it to move forward or backward. Minor imbalances can be overcome by reducing/increasing water flow, or by attaching the dredge to weights placed on the seabed. Excessive lengths of supply hose will also have similar effects, particularly where there is strong tidal flow. Without a tether this movement can tire the diver and also make the dredge harder to control, potentially having a negative impact on archaeological standards. A tether will reduce the mobility, but this can be easily overcome by attaching a 2–3 m (6.5–10 ft) flexible extension to the mouth of the dredge-head. This will enable the excavator to move around the excavation zone much more easily, but care has to be taken not to allow the extension to drag through archaeologically sensitive material.
The position of the compressor on the diving platform depends mainly on the length of available hose, but it is always good practice to minimize trip hazards on the diving platform, so consideration should be given to placing the compressor outlets convenient to the side of the platform nearest to the site. Avoid excessive lengths of hose in the water, as this will cause water drag. Because it is of a smaller diameter the air delivery hose is not quite so affected; nonetheless, it is advisable to anchor the airlift to the seabed, or, where several airlifts are being used, consider the use of a distribution manifold.
(p. 154) Effect of Tidal Flow
Placeing the long water-dredge exhaust downstream of the tidal flow will prevent spoil from drifting back toward the excavation area. However, if the schedule includes working the ebb and flood tides, and spoil drifting back over the excavation area becomes a real problem in maintaining visibility, the only options are to change the position of the exhaust, which can be time-consuming, or perhaps install a second dredge lying in the opposite direction.
Airlift spoil rises up the body of the lift and will tend to follow the tidal flow. Depending on the strength of this flow, fine deposits will travel well away from the site, creating spoil heaps, but heavier material will tend to fall back on top of the excavator or just behind. In some cases, this could be into another excavation area. If the water flow slows or stops, such as during slack-water periods, most of the excavated material will tend to fall back on the excavator. Fixing a tether to angle the exhaust helps, but this reduces mobility and may well not solve the problem entirely. If the problem cannot be resolved, then either different tasks should be undertaken or the excavation should be temporarily terminated until conditions improve.
The primary function of the airlift and water-dredge is to remove excavated spoil from the excavation area in a controlled way, analogous to the wheelbarrow or bucket commonly used on a terrestrial archaeological site. Underwater excavators have an advantage over their terrestrial colleagues in that moving the spoil from the site to the spoil heap is, by comparison, automated. The most sensitive excavation tool is the hand (Figure 6.7), preferably one without a glove, but this may be impractical (p. 155) due to low water temperatures or the hardness of the seabed. Some excavators, even in cold water, will cut off the fingertip of at least one finger of their glove to provide additional sensitivity. When excavating delicate material it is often necessary to use a single finger to painstakingly separate an artifact from its surrounding sediment. Some types of glove, particularly “dry” gloves, do not readily lend themselves to excavation, no matter how warm they may make the hands.
Where it is not feasible to use the hand, other appropriate tools should be selected: for example, a 10 cm (4 in) trowel is often used on harder substrates, and a soft-haired brush can be used for cleaning an artifact prior to photography or drawing. Hand-fanning is also a very common and effective method of excavating loose material. Gentle movement of the hand from side to side will dislodge fine material, with the loose material being sucked toward the dredge or airlift. This technique is also very effective for cleaning artifacts or structures prior to recording. Over-vigorous hand-fanning is likely to result in clouds of silt, reducing the excavator’s visibility. Whatever tool is selected, the utmost care should be taken to avoid damage to archaeological material.
On no account should these suction excavation tools be used as the primary means of excavating archaeological material. This would inevitably result in individual components of fragile artifacts being separated, while organic materials would almost certainly be damaged, if not lost completely, and contextual information will be lost as well.
Good excavation technique should prevent the dredge or airlift from becoming blocked. A piece or cross of wire (or other suitable material) placed at the mouth will prevent larger objects from entering the equipment, but this will not necessarily prevent the mouth from becoming blocked if a large object is allowed to completely cover the working end. It is also advisable to place a trap of some form over the discharge pipe. A net sack is tied over the exhaust end of the dredge on the HMS Swift project, allowing the fine silts that characterize the site to easily pass through the mesh but trapping small finds inadvertently missed by an excavator. The net sack is removed each day and inspected, in part to aid in maintaining provenience information for any artifacts that were accidentally recovered.
One needs training and experience to become a competent archaeological excavator and to be aware of and therefore avoid the associated dangers when using the airlift or water dredge. The main risks to the excavator are entrapment caused by the lines used to anchor the equipment and from loose diving equipment, or even a hand, being sucked into the working end of the tool, if the tool is particularly powerful. One particularly serious eventuality is the second-stage regulator of the alternative air supply becoming trapped in the dredge. The suction can rapidly deplete the contents of a diving tank, as if the regulator was on maximum free-flow, with potentially dangerous consequences for the diver. All personal extraneous diving equipment, especially hoses for gauges and alternative air supply, must be (p. 156) positioned so as to minimize this risk while still remaining accessible. Care should also be taken to prevent large loose pieces of spoil or even archaeological material entering the dredge, to prevent damage and to avoid the consequences of blocking the tool. While this possibility is common to both tools, the significant difference is that if an airlift becomes blocked it will become buoyant and rapidly rise toward the surface, perhaps carrying the excavator with it. A tether will reduce the risk, but anchors also somewhat reduce the mobility of the tool. For both tools, an on/off valve in easy reach of the diver is essential. Quarter-turn valves are quicker and easier to operate than wheel valves, particularly if the diver is wearing thick neoprene gloves or mittens.
Artifact Recovery and Inventory
All artifact recoveries are planned taking into account the need to ensure that an object has been first recorded in situ (sketch, survey, video, photography). There is an agreed-upon recovery method based on the artifact’s physical condition, material, dimensions, and weight; packaging materials that will be required underwater and on the surface to prevent damage during the recovery and transportation to the museum; and the personnel required to carry out the plan. The museum’s conservation staff are consulted to ensure that they are fully prepared to receive the artifact(s). A recovery operation can be a relatively simple affair, or rather more complex when recovering larger artifacts such as cannon, anchors, or even ship structures that may require specialist lifting equipment, but the decision-making process should be more or less the same. The timing of the artifact recovery normally coincides with slack water or shortly before or after; a little water movement can be helpful in maintaining underwater visibility. Typically an appropriate container for the object—generally one with a lid and lined with protective foam—is prepared in advance. If the container is quite large, the foam will increase its buoyancy, so compensatory weights are attached to the container, making the diver’s task easier.
As there are a relatively small number of artifacts recovered during a typical season, the labeling is normally carried out by placing an identification tag in the receptacle prior to the recovery of the artifact to the surface. In the event that there are more numerous objects of a similar category, or where it is deemed better to dismantle an artifact comprising numerous components prior to recovery, such as a stave-built container, it is advisable to label in a sequence that will aid subsequent recording and reconstruction.
Whereas on some projects the archaeological team is responsible for carrying out first-aid stabilization and cleaning, this is not the case on the Swift project. The archaeological team is responsible for the archaeological material from the seabed to the conservation facilities in the Brozoski Museum, where the museum staff (p. 157) takes over, although it is often the case that museum staff will be present on the diving platform to receive the artifacts as soon as they arrive on the surface. Initial cleaning, finds stabilization, and first-aid conservation are part of the museum’s role, along with assistance in handling material during any postexcavation archaeological recording or sampling carried out in the museum by the archaeological team. The complete archaeological collection is held in the museum’s conservation and storage facilities. A conservator contracted by the municipal government is responsible for the conservation and subsequent monitoring of the archaeological collection.
Demobilization and Site Management
Closing the Excavation Area
On completion of the excavation of a particular area or at the end of each field season the exposed area is covered, but the method varies depending on whether the area has been finished or further excavation is planned. In 2006, the excavation in the captain’s cabin in the stern of HMS Swift was completed. The decision was made to replicate a site protection method successfully used on sites in the Netherlands (Manders, pers. comm. 2006). The first stage was to recover the grid to the surface and move the water dredge away from the excavation area, but not to the surface. The exposed area was then covered by a mesh fabric held in place by sandbags to provide an interface between the ship’s structure and the backfill. The exhaust of the water dredge was then positioned to enable spoil to be replaced into the area. A number of dives were required to fill the zone. Finally, a second mesh was loosely placed over the area, again affixed to the structure, rather like the fly sheet of a camping tent. It was intended that the mesh would act as a sediment trap, gradually accumulating material beneath it. During subsequent seasons, inspections have revealed that the method has been quite successful, to the extent that the “free” net is no longer visible.
If researchers plan to return to an area to continue the excavation, the exposed area is covered, ensuring that any partially exposed archaeological material is either recovered or reburied and then protected by a mesh held in place by sandbags, but the active backfilling process is not done. The mesh provides an interface that enables rapid removal of any naturally accumulated backfill without running the risk of inadvertently disturbing or damaging unexcavated archaeological material.
During each field season, at least one public presentation is held in the Brozoski Museum to describe the progress of research resulting from previous seasons and to outline the aims and objectives of the current work. These presentations are an (p. 158) opportunity to recognize the site’s discoverers and early investigators, as well as to publicly thank the local community for their significant contribution to the project. The museum staff prepares a display of the latest discoveries and provides access to the laboratory to allow visitors to see the conservation of the objects that will enhance the museum’s display.
Individuals who have helped in some way are invited to come out to the diving platform to experience the project firsthand. Those that dive, including some members of the original amateur team, are taken on site tours. Local radio and TV interviews are also a part of the project routine, and although they can interrupt the working day, such opportunities are rarely if ever turned down. Maintaining a close connection with the local community, who consider Swift to be part of their heritage, is an important aspect of the project.
A natural extension to the periodic interview or broadcast is to consider maintaining a blog or online “journal” that follows the progress of the project. Such journals can give daily updates and potentially be live. While there are local technical issues, due mainly to the town’s relative isolation, and while admittedly a lack of relevant skills in the team may currently prevent the utilization of this method of outreach, there is no doubt that it will play an increasingly important role in the future and should be considered an option where feasible.
In planning all field-based research projects it is important to understand the relationship between the aims and objectives and the resources required to fulfill them. If they are too ambitious, it may be very difficult to successfully complete them. Inevitably, an archaeologically intrusive project is more complicated than a nonintrusive survey, given the additional components of excavation, finds handling, conservation, and protection of the excavated areas, and all that these phases require in terms of equipment, personnel, and expertise. The HMS Swift project is no exception.
Because of the benign nature of the sinking and advantageous environmental conditions, large parts of the hull and contents survive in excellent condition, although the exposed structural elements are clearly slowly deteriorating. As has already been seen from the array of finds recovered since 1982, the potential for recovering a significant percentage of what was lost with the vessel in 1770 remains high. It would therefore be tempting to undertake a full excavation at some point, if not in the immediate future. However, to do so would inundate the current conservation and storage facility, which does not now have, and is not soon likely to have, the capacity to deal with large amounts of additional material. The current archaeological team would also not be able to cope with the resultant backlog of research. Therefore, the project themes are wisely restricted to those that are achievable (p. 159) within the human, physical, and financial resources currently available, retaining a degree of flexibility to enable unexpected discoveries, such as the human remains.
The site is not under imminent threat from harbor development, although this remains a possibility; and some archaeological sites are threatened by looting, but this is not the case with Swift. Apart from its legal protection, the site is located in a controlled area of the port. More importantly, it is acknowledged by the local population as a very significant part of their local heritage, and as such they play an active role in the site’s protection. The team continues to monitor the situation and is taking steps to understand the options for physically protecting the site. Until any of the above factors change, the project remains committed to studying HMS Swift while preserving as much of the site as possible for future researchers, a key objective of current archaeological thinking.
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