Tag Archives: Global Positioning System

Deep-water Technology: The Future of Maritime Archaeology

While maritime archaeology is a rather new discipline compared to terrestrial archaeology, deep-water archaeology (greater than 100 metres) is so recent that it is still largely in its infancy.  This is due to the extreme conditions of the deep ocean and lack of technology necessary to reach such depths.  In addition, there is the prohibitive cost of deep-water exploration.  Expeditions that use ocean-class research vessels can cost $40,000 USD or $44,697 AUD per day and easily exceed $1 million over a month-long period (Ballard 2008:x).  However, multi-disciplinary projects that foster cooperation with oceanographers, biologists, and engineers can reduce the cost of research and allow each scientist to collect much needed data.  Continuous advancements in the technology of human-operated vehicles (HOVs), remotely operated vehicles (ROVs), and autonomous underwater vehicles (AUVs) are allowing maritime archaeologists to reach greater depths and explore hidden cultural clues in this largely unexplored world.

Techniques commonly used by maritime archaeologists for shallow-water surveys, such as side-scan sonar, magnetometers, and sub-bottom profilers, are being applied to HOVs, ROVs and AUVs to explore the depths of the ocean.  Side-scan sonar emits sound waves that strike the sea floor and creates imagery by recording the timing and amplitude of those sound wave reflections.  Magnetometers are used to locate man-made objects by detecting anomalies in the normal magnitude and direction of the earth’s magnetic field.  Sub-bottom profilers are similar to side-scan sonar in that they emit sound waves towards the sea floor; however, the sub-bottom profiler’s sound waves penetrate the sea floor in order to identify different layers of sediment (Ballard 2008:263-274).  By utilising these devices in conjunction with HOVs, ROVs and AUVs, archaeologists are able to map and survey depths greater than 100 metres.

Human-Operated Vehicles

HOVs are also known as human-operated submersibles or simply submersibles.  Many submersibles are limited in their ability to survey large areas.  This is due to their reliance on a human occupant/operator, which limits the amount of time they can stay on site.  Although HOVs are limited by time, they provide an advantage over ROVs and AUVs because they can “typically lift heavier objects and carry more equipment and/or samples” (Ballard and Coleman 2008:12).  An excellent example of an HOV is Alvin, a U.S. Navy-owned Deep Submergence Vehicle built in 1964.  It is able to dive to a depth of 4,500 metres and remain below the surface for up to  10 hours (WHOI 2013).  Alvin is outfitted with video cameras, lights, and two robotic arms that allow the vessel to carry 680 kilograms of samples.  Alvin is perhaps best known for its involvement in the exploration of RMS Titanic in 1986 (WHOI 2013).

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Figure 1: Human Occupied Vehicle Alvin (Photo by Mark Spear, Woods Hole Oceanographic Institution 2013)

Remotely Operated Vehicles

ROVs are similar to HOVs except that instead of having an occupant inside the vehicle, the ROV is controlled from a support vessel on the surface.  ROVs are tethered to the surface vessel by fibre-optic cables and controlled via fibre-optic telemetry (Gregory et al. 2008:17).  These cables allow the operator to control the movement of the ROV as well other functions such as lighting, cameras and manipulator arms.  ROVs are better adapted for surveying larger areas than HOVs, but are still limited by the cables that attach them to the support vessel.  ROVs are sometimes used in tandem with a towsled that is positioned between the support vessel and ROV.  The benefit of using a towsled is that it absorbs the movement of the support vessel and prevailing sea conditions, which allows the ROV to work undisturbed.  The towsled often sits above the sea floor and provides additional lighting to reduce backscatter from particles in the water when images are being taken.  Besides surveying, ROVs can be used to excavate artefacts from the sea floor.  One example of this type of vehicle is the ROV Hercules and its towsled ArgusHercules is equipped with digital cameras and sonar for site mapping, as well as tube corers to extract samples of sediment in preparation for excavation (Webster 2008:45).  The ROV also features jets that provide a flow of water to clear sediment from artefacts, as well as a suction hose to lift material (Webster 2008:53).  In addition to this useful tool, Hercules’ manipulator arms can be fitted with various hand tools such as brushes and scrapers (Webster 2008:56).

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Figure 2:  ROV Hercules viewed from towsled Argus (NOAA 2013)

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Figure 3: Towsled Argus being lowered into the water (NOAA 2013)

Autonomous Underwater Vehicles
AUVs differ from the two previously mentioned vehicles in that they are not controlled by an operator but rather programmed to survey a certain area.  In addition to not requiring an operator, the major advantages of AUVs over HOVs and ROVs is that they can be deployed and left to survey large areas for between 24 and 72 hours without the need for a support vessel.  This saves thousands of dollars in operating costs (Bingham et al. 2010:703).  While AUVs tend to be used more for commercial purposes, such as surveys for natural resources, their role in archaeology is significant and growing.  AUVs have precise on-board navigation systems that make use of global positioning system (GPS) and differential global positioning system (DGPS) that link to the support vessel.  The exact position (3-5 metre accuracy) of the AUV is essential to mapping and surveying the sea floor (Warren et al. 2007:4).  Many AUVs carry chemical sensors for testing the environment in addition to multibeam sonar (similar to side-scan sonar), a sub-bottom profiler, and magnetometer.  AUVs are limited by the power supply needed to both run the vehicle and maintain its illumination lamps (Bingham et al. 2010:703).  Despite their limitations, AUVs are ideal for conducting general surveys and producing photomosaics of the sea floor with limited detail.  A great example of AUV application within deep-water archaeology is the SeaBED model used to document the Chios shipwreck site in the northeastern Aegean Sea (Bingham et al. 2010:702-715).

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Figure 4: Model of SeaBED AUV being deployed (Bingham et al. 2010:705)

The future of maritime archaeology is continually evolving as technological advances in various underwater vehicles allow for the ocean to be explored and mapped at greater depths.  Multi-disciplinary cooperation has facilitated archeologists’ access to these forms of technology and increased the amount of data they can collect.  This in turn has enabled the discovery and documentation of ancient shipwrecks and landscapes previously unknown to modern archaeology.

References

Ballard, R. and D.Coleman

2008 Oceanographic Methods for Under Archaeological Surveys. Archaeological  Oceanography, edited by Robert Ballard, pp. 3-14. Princeton University Press, Princeton, New Jersey.

Ballard, R.

2008 Glossary. Archaeological Oceanography, edited by Robert D. Ballard, pp. 263-274. Princeton University Press, Princeton, New Jersey.

Ballard, R.

2008 Introduction. Archaeological Oceanography, edited by Robert Ballard, pp. ix – x. Princeton University Press, Princeton, New Jersey.

Bingham, B., B. Foley, H. Singh, R. Camilli, K. Delaporta, R. Eustice, A. Mallios, D. Mindell, C. Roman, and D. Sakellariou

2010 Robotic tools for deep water archaeology: Surveying an ancient shipwreck with an autonomous underwater vehicle. Journal of Field Robotics 27(6): 702-717.

Gregory, T., J. Newman, and J. Howland

2008 The Development of Towed Optical and Acoustical Vehicle Systems and Remotely Operated Vehicles in Support of Archaeological Oceanography. Archaeological Oceanography, edited by Robert Ballard, pp. 15-29.  Princeton University Press, Princeton, New Jersey.

National Oceanic and Atmospheric Administration

2013 Hercules (ROV) and Friends, Electronic document, http://oceanexplorer.noaa.gov/technology/subs/hercules/hercules.html, accessed 10/9/13.

Warren, D., R. Church, and K. Eslinger

2007 Deepwater Archaeology with Autonomous Underwater Vehicle Technology. In Offshore Technology Conference. Houston Texas Electronic Document, e-book.lib.sjtu.edu.cn/otc-2007/pdfs/otc18841.pdf, accessed 10/9/13

Webster, S.

2008 The Development of Excavation Technology for Remotely Operated Vehicles. Archaeological Oceanography, edited by Robert Ballard, pp. 41-64 Princeton University Press, Princeton, New Jersey.

Woods Hole Oceanographic Institution

2013 Human Occupied Vehicle Alvin. Electronic document, http://www.whoi.edu/alvin/, accessed 9/9/13.


Finding A Shipwreck You Can’t See: Detection and Survey Methods from Hinchinbrook Island

By Kurt Bennett

I have just finished a week-long field practicum in tropical Queensland. The field practicum took place on Hinchinbrook Island between the 7th and 14th of July. Five students (including myself) from Flinders University helped the Heritage Branch of the Department of Environment and Heritage Protection (QLD) locate possible shipwreck sites. Multiple survey methods were employed to locate cultural material buried beneath the sand. This blog will focus on one site that was investigated during the field practicum. It is located on the north end of North Shepherd Bay (Figure 1).

Figure 1: Location of the ‘possible’ shipwreck and our campsite (Google 2013).

Figure 1: Location of the ‘possible’ shipwreck and our campsite (Google 2013).

Queensland Parks Service observed timbers in North Shepherd Bay after Cyclone Yasi, in 2011, removed sand from the beaches on the eastern side of Hinchinbrook Island. The GPS (Global Positioning System) coordinates were taken and passed on to Paddy Waterson, Senior Heritage Officer at the Heritage Branch. The pictures taken by Parks resembled possible ships timbers. On Monday the 8th July and Friday the 12th 2013, the GPS points were visited. The GPS points were located approximately 3.6 kilometres (km) from our campsite (South Macushla) along a walking track. The walking track finished on the southern end of North Ramsey Bay and required a 1.6 km walk along the beach to the approximate area. No cultural remains were visible upon arrival and therefore certain archaeological methods were needed to locate the previously seen cultural material. The following will discuss the methods employed in order to find the cultural material and determine what remains on the beach.

The first step was a mixture of two methods using both a GPS and a metal detector. The aim was to locate the original marks with the GPS and establish a central point for what was originally witnessed. A 20 metre (m) square was placed around the central GPS point, marking an area to be metal detected. The metal detector, Excalibur II, was set to exclude non-ferrous metals. This enabled the metal detector to detect iron concentrations. The metal detection was systematically executed, with the user following an east-west pattern every one metre along the 20 m grid. Every ‘hit’ was marked with a pin flag and measurements taken using the baseline offset method (Figure 2).

Figure 2: Metal detector hits with baseline. Photo facing NE, North Shepherd Bay (Kurt Bennett, 8 July 2013).

Figure 2: Metal detector hits with baseline. Photo facing NE, North Shepherd Bay (Kurt Bennett, 8 July 2013).

Once the designated area had been covered and all the hits were marked, the next step was to probe the points of interest (hits). This was to determine whether solid material was buried beneath the sand. Both metal and wood were detected, with metal being distinguishable from wood due to the vibrations and the sudden jolt felt by the probe, as opposed to the stickiness felt with waterlogged wood. The probing also indicated the depth of cultural material. The wood and metal was located at a depth of approximately 30 centimetres (cm) below the sediment surface. The sand proved to be a challenge to probe as it was wet and compacted due to being located in the intertidal area.

Once the probing indicated there was material below the beach surface, a 1 m square was placed around the GPS point; this also proved to be a concentration of iron from the metal detection survey. The trench was then excavated with shovel and trowel until material was found. Timber was uncovered, which was possibly a ship’s timber with an iron brace and a treenail (Figure 3). Photographs and measurements were taken of the timber. The trench could not be excavated any deeper than 30cm due to water seepage caused by the intertidal zone. Therefore only the top face of the timber and iron brace was seen, with the rest left submerged in watery sand. The trench also uncovered rocks that were thought to be metal when detected by the probe. This posed a challenge when trying to distinguish between metal and rock, as the rock had the same reaction as metal when probed.

This became more evident when the site was revisited on Friday the 8th.  Photographs were taken of the uncovered timber and the trench was backfilled. Our investigation was limited due to the tide and daylight dictating the time we could spend at the beach. The trench could not have been dug if the tide was in and therefore the site had to be visited during low tide. This left the team approximately four hours to investigate the site. Not to mention we had to be back at camp by nightfall for health and safety reasons. Apparently dusk is the time that crocodiles come out to feed, and that is definitely not the way I planned on finishing my field practicum.

Figure 3: One metre square excavated showing ships timber, North Shepherd Bay. Timber being measured by Flinders students (Kurt Bennett, 8 July 2013).

Figure 3: One metre square excavated showing ship’s timber, North Shepherd Bay. Timber being measured by Flinders students (Kurt Bennett, 8 July 2013).

North Shepherd Bay was revisited on Friday the 12th and this time the aim was to establish the full extent of the site. Again the metal detector was employed and this time we extended our square to 20 m north south of Monday’s metal detection area. To our disappointment the hits did not resemble the shape of a ship’s hull, but more a scatter of debris. This was still exciting, as it could still resemble a wrecking event. The only way to find out was to dig and dig we did!

Several holes were dug, with the longest being over four metres in length (Figure 4). This trench was a continuation from the previous ship timbers. Two additional timbers were uncovered and what appeared to be the beach substrate with a rocky base. It proved to be a little frustrating, since we set out to find a shipwreck. The timbers uncovered were measured and detailed drawings were produced, providing an accurate recording of what had been found. The lengths of the two timber were approximately 1.5 m. The rest of the metal detector hits uncovered a mixture of items that may have washed in over time, including a chain block and pulley, and buried car batteries. The metal detection survey was extended a further 250 metres, walking south along the beach, but it had to be cut short due to daylight running out.

Figure 4: Red arrows indicating points of interest dug for material. Photo facing SE, North Shepherd Bay (Kurt Bennett, 12 July 2013).

Figure 4: Red arrows indicating points of interest dug for material. Photo facing SE, North Shepherd Bay (Kurt Bennett, 12 July 2013).

The aim of visiting North Shepherd Bay was to investigate the known GPS marks. The timbers uncovered and seen after the cyclone may be a result of washed up material, possibly from a shipwreck in another location, or they could be the last remaining pieces of a shipwreck. The methods employed were systematically executed to try and determine if a shipwreck lay beneath the sand, however our thorough searching and non-stop digging proved it was a beach littered with cultural material that could span a whole century. The methods mentioned above will provide a basic plan for any archaeologist wishing to investigate buried shipwrecks on a beach.

The Cultural Maritime Landscape of Ramsey Bay, Hinchinbrook Island

By Daniel Petraccaro, Master of Maritime Archaeology Student (Flinders University)

Introduction

The maritime archaeology fieldwork on Hinchinbrook Island (figure one) was conducted by the Queensland Department of Environment and Heritage Protection (DEHP) with the grateful support of the Hinchinbrook National Park. The aim was to locate, identify and record the maritime heritage sites on and around Hinchinbrook Island. This blog will discuss two sites investigated: The wreck of Belle in Ramsay Bay (figure one; figure two) and a nearby concentration of possible ships’ fittings to the south of Belle. Masters students and staff from the Flinders University Archaeology Department were lucky enough to assist DEHP with the recording and interpretation of maritime archaeological sites on the island.

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Figure One: Map of Hinchinbrook Island and Location of Belle in Ramsey Bay. Google Earth.

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Figure two: Belle after Cyclone Yasi in 2011. http://www.townsvillebulletin.com.au/article/2011/09/03/263161_news.html. Accessed 25/07/13.

Using the archaeological results of the fieldwork, I will discuss in this blog how the sites investigated at Ramsey Bay are interconnected within the concept of a maritime cultural landscape. I will also hopefully show how human behaviour and the natural landscape play a part in the maritime setting. The maritime cultural landscape signifies human utilisation (economy) of maritime space: boats, settlement, fishing, hunting and shipping (Westerdahl 1992: 5).

Background: Hinchinbrook Island

Hinchinbrook Island is the perfect tropical paradise. The island is part of the Great Barrier Reef Marine Park and protected within the Hinchinbrook Island National Park. Hinchinbrook Island is eight kilometres east from the Queensland coast at Cardwell (figure three). Spectacular natural vegetation includes mangroves, scrublands and tropical rainforests. Sandy isolated beaches and the view from the prestige coastline are breathtaking! If you are interesting in visiting the island, the only way to access Hinchinbrook Island is using shipping transport launched from Cardwell or Lucinda; if you are prone to seasickness, I suggest you bring some medication along!

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Figure three: Sunrise at Cardwell. Hinchinbrook Island in the distance. Photo courtesy of Daniel Petraccaro

Historical Background: Hinchinbrook Island    

I found most of the historical research on Hinchinbrook Island in Douglass Barrie’s book: Minding My Business; an interesting read. Hinchinbrook Island contains natural resources extracted by European Australians from the 1850s until the early 1930s. Cedar oak, a valuable hardy timber, was logged during the 1850s (Barrie 2003: 120). Shell middens were also mined during the 1860s and processed into lime (Barrie 2003: 121). The lack of jetty structures, the isolated conditions of the island, and shallow bays (figure four) made for difficult access, which in turn prevented the further development of these industries. Sugar plantations were also established on the island during the late 1800s but were abandoned due to seasonal cyclone damage and gale force winds (Barrie 2003: 121 – 123).

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Figure four: Flat tidal zone ( tide is out) at Ramsey Bay. Photo courtesy of Daniel Petraccaro

The Hinchinbrook Channel was also an important shipping route from the 1850s until the early 1900s (Barrie 2003: 114, 117, 124). The 22 kilometre channel separates the mainland from the island (figure one). The channel was an important trading route for vessels shipping cedar from the great forests in Cairns and Atherton to Melbourne and Sydney (North Queensland Register 1900: 31). The Hinchinbrook Channel was also an important route, as much of the surrounding Great Barrier Reef was uncharted and exposed by strong winds and waves.

The Shipwreck Sequence at Ramsey Bay, Hinchinbrook Island

Ramsey Bay was of interest to this field study due to historical accounts of four ships known to have wrecked while attempting to retrieve a cargo of cedar washed up on shore after the Merchant wrecked on the 5th March 1878 (North Queensland Register 1900: 31). Merchant was a steamer built in the USA in 1862. While Merchant was en route to Melbourne from Port Douglas, the ship hit a reef and vanished. The exact wreckage location of Merchant was never found. Once reports reached Cardwell of the cedar logs washing up in Ramsey Bay, the Harriet Armitage (Barque) was sent to retrieve the cargo (North Queensland Register: 1900: 31). The cedar was considered more valuable than the lives sent on the salvage mission (Barrie 2003: 111). Despite the efforts of Harriet Armitage, gale winds in Ramsey Bay caused the ship to run ashore and wreck in July 1879. Three other ships followed Harriet Armitage, unfortunately, strong gales caused all three ships to wreck in Ramsey Bay. Charlotte Andrews (Barque) wrecked in October 1879, Rebecca Jane (Brigantine) wrecked in July 1880 and Belle (figure two; figure five) (Brigantine) wrecked in February 1880 (Morning Bulletin 1925: 5). The cedar was eventually salvaged by a fifth shipping vessel and sold at auction in Townsville (Morning Bulletin 1925: 5).

The Natural Landscape at Ramsey Bay, Hinchinbrook Island

The natural landscape played a crucial role in the wreckage sequence and process at Ramsey Bay. While Merchant struck a reef hundreds of kilometres away, winds and strong surf caused the cargo to drift until it finally beached at Ramsey Bay.  One survivor from the Harriet Armitage noted the tremendous surf on the beach and claimed the wind and sea rose extremely rapidly (North Queensland Register 1900: 31). Without any jetty infrastructures, the shallow waters also proved to be a difficult task for ships trying to reach Ramsey Bay, the only logical access point for the vessels trying to retrieve cargo washed onto shore. Ramsey Bay is naturally encompassed by mangrove forests to the north-east and south (figure one; figure five), which is impossible to travel through by foot or sailing vessel.

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Figure five: Ramsey Bay showing the location of Belle and southern artefact concentration. Google Earth.

The Maritime Cultural Landscape at Ramsey Bay

You would be surprised to hear of the amount of rubbish washed up on Ramsey Bay. The dunes were littered with bottles, plastic, iron drums, wood and the largest variety of thongs I have ever seen. While one might only see rubbish, I saw a landscape and a deposition event that has occurred within the bay for the past 150 years. It was an interesting task rummaging through the rubbish hoping to find the remains of a wreck! No luck, however. Similar to how the rubbish had washed up on  shore, it is easy to forget the cargo of cedar timber followed the same pattern when it washed up in Ramsey Bay in 1878.

It is also interesting to note that Cyclone Yasi in 2011 (figure six) drastically altered the maritime landscape. The cyclone caused a drastic change in the sand dune, exposing the wreckage of Belle (figure two) (Waterson 2012) and a site called ‘Southern Artefact Concentration’, located eight-hundred and fifty meters south from Belle. However, during the current fieldwork, shifting dune sands had covered most of Belle and the remains of ‘Southern Artefact Concentration’ under a minimum of 10 cm of sand, suggesting the sand dune has recovered since the cyclone two years ago. The remains of Belle identified during previous surveys include the frames, metal brackets and windlass (Waterson 2012). Iron cable was also identified west of the ship’s bow. During the current fieldwork, the remains of iron bolts, rods and mast caps (courtesy of Paddy Waterson who helped with the identification) (figure seven; figure eight) were identified within the upper tidal zone and sand dune at ‘Southern Artefact Concentration.’

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Figure six: Path of cyclone Yasi in 2011. bom.gov.com.au. Accessed 25/07/13.

Discussion: The Maritime Landscape at Ramsey Bay, Hinchinbrook Island

The results of both Belle and the ‘Southern Artefact Concentration’ suggest there is evidence of interaction between the sea and the wreckage history of shipping vessels at Ramsey Bay. The identification of Belle within the tidal zone at Ramsey Bay supports the theory that strong winds and surf caused the ship to wreck. One newspaper article states that Belle, when fully loaded, parted her cables and drifted ‘whole’ onto the beach (Morning Bulletin 1925: 5). The location of the cables east of Belle were identified during the study and therefore conform to the historical accounts regarding how the ship wrecked. Furthermore, the lack of any remains from Belle conforms to historical accounts that the cargo was eventually salvaged. The mast caps identified from  ‘Southern Artefact Concentration’  are from either Belle or another wreck (figure seven; figure eight). The results support the theory that remains such as  wood and other cargo was salvaged, while the mast caps and another other iron items were left behind.

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Figure seven: (LEFT) Mast Caps from ‘Southern Artefact Concentration’. Photo Courtesy of Paddy Waterson.
Figure eight: (RIGHT): Mast caps. (Paasch 1890: plate 93).

The natural landscape could aid in identifying the possible location of the other known wrecks in Ramsey Bay. Belle was known to have wrecked during strong gale winds so there is no surprise the ship ended up stranded in the tidal zone (figure five). The three other wrecks known to have wrecked in Ramsey Bay are also most likely to be located in the tidal zone. The three other ships all were wrecked during strong winds while trying to salvage timber. They are most likely to be located within the same vicinity as Belle. These wrecks are also likely to be salvaged and therefore few archaeological remains would be present.

Summary: The Cultural Maritime Landscape of Ramsey Bay

The sea and the maritime cultural landscape of Hinchinbrook Island have influenced the economic development and wrecking process of shiping vessels at Ramsey Bay. Merchant wrecked while attempting to travel from Cairns to Melbourne following charted trading routes and the Hinchinbrook Channel. It is clear that the sites and shipwrecks identified at Ramsey Bay have resulted from salvage events, commencing with the cedar timber cargo from Merchant. The only way to salvage cargo at Ramsey Bay is via ship. However, the shallow coastline, gale winds and tides at Ramsey Bay caused the wreckage of four ships. The cedar and the shipwrecks were eventually salvaged. Items with little monetary value, such as iron, were left behind. Therefore, when examining a maritime landscape, it is important to include all factors relating to, and influencing, the maritime activity within an area. Overall, this type of archaeological investigation shows how human behaviour and natural landscapes play an important part in the maritime setting. In summary, I hope you have all learnt something about the cultural maritime landscape history of Ramsey Bay!

Acknowledgements

A special thanks to the Department of Environment and Heritage Protection (DEHP) for allowing the Flinders students to participate in the fieldwork, and, the Hinchinbrook National Park for granting access. A warm thanks goes out to Paddy Waterson (DEHP), Amelia Lacey (DEHP) and Ed Slaughter (Queensland Museum).

References

Barrie, Douglas 2003.  Minding my Business: The History of Bemerside and the Lower Herbert River District of North Queensland Australia. S and D Barrie, Ingham, Queensland.

Morning Bulletin 1929. http://trove.nla.gov.au/ndp/del/article/54641887. Accessed 22/07/2013.

North Queensland Register 1900. http://trove.nla.gov.au/ndp/del/article/82342975. Accessed 22/07/2013.

Paasch, Hermann 1890. Illustrated Marine Encyclopedia. Argus Books, England.

Waterson, Paddy 2012. Shipwreck Heritage: The Belle. Unpublished powerpoint report. QEHP, Queensland.

Westerdahl, Christer 1992. The maritime cultural landscape. The International Journal of Nautical Archaeology 21(1):5-14.