Year 1 (Dive and Geophysics)

Assessment, Evaluation and Recording - Round Two

(Aggregate Levy Sustainability Fund – more on the ALSF).
 
Read the project background for round two of this project or to view the map click here.
 

Project Background

The aim of Round 2 of Wrecks on the Seabed is to provide industry, regulators and contractors with a framework for a staged approach to the investigation of wreck sites. Such a framework is important when considering the time and cost of marine investigations. It is also helps effective communication between industry, regulators and contractors. The project design for Round 2 of Wrecks on the Seabed builds on the experience of Round 1 of the project.
 
The project addresses the following aspects of wreck site investigation:
  • A geophysical survey of a 2x2km area of seabed presents an opportunity to develop methodologies for the survey of ephemeral wreck sites.
  • With the dredging industry moving into deeper water, one of the key points emerging from industry is the applicability of wreck investigation methods to greater water depths. The geophysical and Remotely Operated Vehicle survey of three unknown wreck sites in water depths between 46 and 60m will serve as a basis for the development of effective methods for assessing, evaluating and recording wreck sites in deeper water.
  • As most of the problems encountered during the diving fieldwork of Round 1 were related to the size of the diving vessel, a larger Remotely Operated Vehicle / diving support vessel will be deployed in Round 2 of the project. An analysis of the costs and benefits using larger vessels will be carried out.
  • Four of the wreck sites investigated by divers in Round 1 of the project will be revisited with an Remotely Operted Vehicle in Round 2. This will allow a direct comparison of Remotely Operated Vehicle and diver based results.
  • The project results will be made available to the public through web pages, brochures, lectures, conferences and diver information packs for recreational divers.
As the project is specifically tailored to the requirements of marine aggregate dredging, the study areas and sites chosen are all situated close to existing or intended marine aggregate extraction areas.

Round Two Methodology

Dummy

Work Support Vessel

The MV Flatholm from Coastline Surveys Limited was used as the work support vessel throughout the 2005 field sessions. The Flatholm is a converted harbour tug, built in Japan in 1976. The vessel has a length over all of 23.3m, a breadth over all of 8.0m and a 2.6m draft.
 
The Wessex Archaeology Remotely Operated Vehicle and diving operations were directed from a control room, permanently installed on deck aft of the superstructure.

Mooring System

Throughout the Remotely Operated Vehicle session Flatholm was moored on a four point mooring above the wrecks to be surveyed.
 
The vessel's two bow anchors were used at the front and two 200kg high power holding anchors with short lengths of chain were deployed at the stern. Two hydraulic winches were used to handle the stern mooring.
 
For the mooring procedure a computer file (.dxf) showing the wreck outline visible in the geophysical survey was displayed in the vessel navigation software package on the bridge. Points were taken where anchors were to be dropped, so as to avoid damage to the wreck. However it was not always possible to avoid mooring wires crossing the wreck site.
 
As the two 200kg anchors used as stern mooring during the Remotely Operated Vehicle session proved insufficient to hold MV Flatholm on station in strong tides and less favourable weather conditions, two sinkers of 2t and 3t respectively were bought for the diving session.
 
A 40m length of chain with a buoy and a shackle at the end was attached to each sinker. The use of sinkers required a lengthy mooring procedure to avoid dragging long wires through the water and damaging wreck sites.
 
On arrival on site, the two buoyed sinkers were dropped on one side of the wreck and their positions marked. The vessel than deployed the bow anchors on the other side of the wreck site and then dropped back. Then the stern winch wires were connected to the sinkers using a small rigid inflatable boat.

The Acoustic Tracking System

An Ultra Short Baseline (USBL) SCOUT acoustic tracking system from Sonardyne was used during all fieldwork sessions to track the Remotely Operated Vehicle and divers.
 
The SCOUT system consists of three main components: the vessel mounted acoustic transceiver, one or more Remotely Operated Vehicle or diver mounted transponders and the surface command module running the control software.
 
In a USBL system, the position of subsea targets is calculated by measuring range and bearing from the vessel mounted transceiver to the submerged transponder, which emits acoustic signals.
 
In a short baseline system, only one transducer (transponder on the seabed) transmits sound, but many transducers on the surface receive signals. In a USBL system such as SCOUT this array of transducers is built into a single transceiver assembly. The baselines between the individual transducers are very (ultra) short, usually in the range of centimetres.
 
The waterproof and portable surface command module running the SCOUT USBL software was installed in the control room.
 
 
The SCOUT USBL Transceiver was mounted on a pole over the side of Flatholm. In order to provide maximum stability for the transceiver the pole had a diameter of 10cm and was attached to a bracket welded onto the rail and supported by another bracket further down the ship’s side. The pole could be swivelled up when Flatholm was in passage.
 
SCOUT’s very light and rugged Type 7815 HF transponders could easily be attached to either the Remotely Operated Vehicle or diver umbilicals.
 
The transponder worked on frequencies between 35 and 55kHz. The stated operating range for the system was 500m and the acoustic coverage was +/- 90 degrees below the transceiver.
 
Even when moored, a vessel yaws, pitches and rolls. As the calculated diver/Remotely Operated Vehicle position is based on the transceiver position, this movement introduces inaccuracies into the positioning and has to be compensated. The SCOUT system allows tracking in two modes: The transceiver includes an internal heading and attitude sensor, which can be used for compensation. Alternatively an external motion reference unit (MRU) and a gyrocompass can be used to compensate for vessel movements.
 
Using the system on internal sensors is easier, as no external instruments have to be configured, but this decreases the stated accuracy of the system from ± 0.5% of the slant range to ± 2.75% of the slant range.
 
For both the Remotely Operated Vehicle and diver fieldwork sessions, an external MRU and gyrocompass were installed on the Flatholm.
 
A TSS HRP-10 MRU was fitted in the survey container. X, Y and Z offset values to the transceiver were entered in the SCOUT software.
 
An ASG Brown Meridian Surveyor gyrocompass was also installed in the survey container and positioned exactly parallel to the vessel's lubber line.
 
An onboard GPS provided positioning information. The GPS was a CSI Vector Sensor Differential GPS capable of sub-metre accuracy.
 
Prior to the fieldwork, all instruments were surveyed on the vessel with the help of a total station by a Wessex Archaeology surveyor to achieve the highest possible positioning accuracy. The offset values to the USBL transceiver were entered into the SCOUT software. All external instruments were connected to the SCOUT surface command module.
 
Both external and internal sensors had to be calibrated before use. This required the Flatholm to sail predefined patterns around a transponder on the seabed and to steam a full 360 degree circle. A calibration wizard in the SCOUT software automatically applied the necessary corrections to the USBL settings.

The Recording System

Since 2002, Wessex Archaeology has developed a Microsoft Access based diver recording system known as ‘DIVA’ which can be used for real time recording of three-dimensional positions and information in conjunction with the mapping programme ESRI ArcGIS 9.0.
 
DIVA consists of a Microsoft Access database which stores the information, and a GIS interface for graphic display. This system was used in Round 1 of the project and has since been further improved.
 
The position of the tracked vehicle or diver is output from the Sonardyne SCOUT surface command module in real world co-ordinates and can consequently be displayed in real time on top of geophysical survey data in ArcGIS 9. The vehicle or diver track can also be displayed and saved separately.
 
 
To allow integration with the previously acquired geophysical survey data, Universal Transverse Mercator (UTM) coordinates, based on the WGS84 datum and the WGS84 ellipsoid were used for display and recording. The targeted wrecks were spread over UTM zones 30N and 31N.
 
A laptop running DIVA and ArcGIS was set up in the survey container, so that the recorder could see the screens showing the underwater footage being collected by the ROV and divers.
 
 
Observations made by divers or recorded from the Remotely Operated Vehicle video feed can be entered into the database by the recorder. These observations, stored in the DIVA database, include the three-dimensional position, comments typed in by the recorder and mapping labels for the display in the GIS system.
 
 
Observations can be taken as quick, but less accurate, spot fixes, or as average fixes. Average fixes obtain a number of positions over a short period of time and calculate an average position for the diver or tracked vehicle using a software application developed by Wessex Archaeology and known as Accu-fix. The more accurate average fixes were generally used for recording datum points and important features on the wrecks.
 
Diver observations can be displayed as different layers in ArcGIS, grouped for example by mapping labels, observation type, etc.
 
A summary form allows the archaeological supervisor to summarise individual dives, whole events and monuments. The diver can also enter archaeological, environmental and operational summaries. Paper records such as drawings can be referenced to individual diver observations.
 
A general log allows the archaeological supervisor to keep track of daily events, working hours, weather forecast and tidal predictions.
 
Records of earlier events, such as the Round 1 diving or the collection of geophysical data were readily available in the DIVA database. This was a useful source of reference and comparison, especially where earlier diver observations were concerned.

ROV Operations

The Remotely Operated Vehicle (ROV) survey of shallow wreck sites took place between the 11 and 26 June 2005. The survey was carried out from the MV Flatholm, Coastline Survey with two Wessex Archaeology staff acting as archaeological supervisor / tender and recording system operator to carry out the recording, and an external ROV operator.
 
The ROV and pilot were supplied by SUBCO Underwater Equipment. A Seaeye 600 high power inspection and observation ROV was used throughout the project.
 
The 1m long and 76cm wide ROV weighed 75kg. It was powered by 4 thrusters which provided a maximum forward speed of 2.5 knots. The ROV was supplied with 150m of umbilical. The maximum payload was 10kg.
 
picture m9picture m9
 
The ROV had two integrated cameras: a PAL colour camera; and a low light black and white (B/W) camera. Two 150 watt lights were dimmable and could be tilted together with the cameras to ± 80 degrees.
 
The ROV was equipped with forward scanning sonar for navigation, a built in fluxgate compass and a digital depth gauge. Information from these instruments could be displayed over the video output.
 
The surface controls consisted of an isolation transformer, the main ROV surface unit for power distribution, a hand controller with joystick, two screens and a Panasonic digital video capture unit. Video was recorded on miniDV tapes.
 
 
The ROV surface unit was installed in the survey container on deck. The umbilical was stowed on deck. Even though the ROV could be safely handled manually it was usually launched and recovered with the crane on deck.

Diving Operations

The diving survey was split in two units of 15 days with a six day break in between and took place between 4 July and 8 August 2005. Again MV Flatholm of Coastline Surveys was used as support vessel. The project staff consisted of five archaeologists and three crew aboard MV Flatholm. The archaeological team consisted of four divers and an archaeological recorder. Diving roles were rotated within the team. Two divers were appointed as diving supervisors.
 
All dives were conducted using surface supplied diving equipment with Kirby Morgan 28 band masks.
 
 
The diving panel, communication box and video recording equipment were set up in the survey container next to the recording computers and the SCOUT system. The air supply consisted of five 300bar J-bottles secured to the outside of the survey container. After each dive the cylinders were recharged using an onboard diesel HP compressor.
 
On the starboard side of the vessel a gate was cut into the rail to provide safe access to the water via a diving ladder. The umbilicals were stowed on the open working deck.
 
The dive team generally consisted of diving supervisor and recording system operator in the survey container, standby diver and tender on deck and one diver in the water. On some of the shallower sites the standby diver was used in-water alongside the main diver to aid with recording or to obtain digital video and stills footage of the main diver.
 
Every dive was recorded on miniDV tape using a colourwatch digital video system with hat mounted camera. A Canon Powershot G2 in Ikelite housing with Ikelite DS 125 substrobe was used to take digital still photographs. A .56 Sea and Sea wide-angle lens allowed the photography of larger objects from close distances.
 
On night dives and deeper sites with low visibility a 100 Watt Lumb Bros FIII underwater torch was employed.
 
In addition to the diver recording system based on acoustic tracking, conventional recording methods, such as offset drawing, were used on the dived wreck sites.
 
Depending on the desired level of recording, underwater photography, videography, sketches and drawings were used. Trilateration and offset measurements were acquired with folding rules or tape measures.
 
You can see how the methods worked by looking at the Bottle Wreck. This wreck was recorded using traditional marine archaeologcial methods. A 32m by 10m grid was established around the visible remains of shipwreck and cargo. The pipe cargo mound and individual artefacts were then drawn in relation to the grid using offset and trilateration methods. To link the site grid to real world co-ordinates accurate fix points were taken for each of the grid corner points with the USBL system. To speed up the drawing and recording process, measurements were obtained by the diver, but the drawing was carried out by the supervisor on the surface. This was done using the live video link provided by the colourwatch system.

Remotely Operated Vehicle Fieldwork Summary

The work support vessel MV Flatholm was mobilised on 11 June 2005 at Lowestoft. The acoustic tracking system was installed and secondary instruments such as GPS and gyrocompass measured in. After loading and setting up the Remotely Operated Vehicle equipment, a test dive was conducted in Lowestoft harbour.
 
The transit to site took place on the 12th June 2005, and the first wreck was surveyed on the 13th June.
 
Altogether 20 Remotely Operated Vehicle dives were conducted on seven different sites in 10 days. Two days were down days due to strong winds (above force 6). The total bottom time for the 20 conducted dives is 1431 minutes, or 23.85 hours. The table below provides further details of the sites dived by Remotely Operated Vehicle:
 
WA ID
Wreck  Name
Dive
Days
Down
Days
No of
Dives
Bottom
Time/min
5004
SS Concha
2
-
3
340
5005
SS Umba
2
-
3
241
5006
SS Devon Coast
2
-
3
54
5009
Unknown
1
-
3
280
5011
Unknown
2
1
4
182
5013
Unknown
1
1
2
200
5014
SV Thomas Lawrence
1
-
1
94

Diving Fieldwork Summary

At the start of the first diving session, unfavourable weather conditions forced MV Flatholm to stay in Lowestoft, so that the diving equipment had to be mobilised in Lowestoft instead of Shoreham as planned. Five days fieldwork time were lost due to weather at the start of the session.
 
The remaining session was spent on site 5013, the so called ‘Bottle Wreck’. On the second session, the equipment was mobilised and demobilised in Shoreham. Two wrecks, site 5009, the ‘1906 Wreck’ and site 5004, the ‘Concha’ were surveyed.
 
Altogether 55 dives were conducted on three different sites in 19 days. Nine days were down days due to bad weather or technical defects. The total bottom time for the 55 dives is 2295 minutes or 38.25 hours. The table below provides further details on the sites that were dived:
 
WA ID
Wreck  Name
Dive
Days
Down
Days
No of
Dives
Bottom
Time/min
5004
SS Concha
5
2
13
675
5009
Unknown
6
2
13
455
5013
Unknown
8
5
29
1165

 

The Wrecks

Dummy

View the map

Click the spots on the map below to explore the wrecks. You may also view a map of the wrecks dived in Round I.

Location mapWreck 5013 Wreck 5004 Wreck 5009 Wreck 5005

 

The Ore Wreck (Site 5004)

Click the red labels on the image below to see underwater photographs. Scroll down to read about the wreck and to the bottom of the page to see videos from the wreck.
 
 

Plan of wreck 5004Buried Flywheel Anchor Winch 1 Donkey Boiler Main Boiler Main Boiler Engine Engine Coupling Propeller Bow Section

Location

The Ore Wreck is located 7.5nm SSE of Littlehampton in West Sussex, between the Outer Owers and Kingmere Rocks. The wreck position is 50 40.750N, 00 28.783W (Geodetic co-ordinates, WGS 84) or E 677954.12, N 5617253.31 (UTM Zone 30N, WGS 84). The wreck lies at a general depth of 10.7m (CD). Depths experienced on site ranged from 16m to 20m.
 
The seabed on the site consists of sand and sandy gravel, with a covering layer of dead shells.
 

What is left on the seabed?

Bow SectionBow Section The wreck is lying on even keel with a slight list to port on a fairly flat seabed. It is orientated northwest - southeast with the bow in the southeast. As the layout of the wreck is clear, the descriptions refer to port, starboard, bow and stern.
 
The site, including the debris field, measures 74m x 20m. The wreck itself measures 67m x 8m. From the propeller at the stern to the first cargo hold, the wreck forms a line on the seabed, but the bow section is broken off and lying at an angle to the starboard side.
 
In general the hull structure is heavily eroded and where present only survives to a level of one metre proud of the seabed. The most prominent feature on the site is the engine room 20m forward of the stern. Here, the two cylinder compound steam engine and the main scotch boiler are fully intact and stand 3.36 and 3m proud of the seabed respectively.
 
At least three cargo holds, two forward of the engine room and one aft are represented by square concreted mounds of iron ore. The aft hold or holds measure 10m by 8m and stand 2.5m proud of the seabed. No.2 hold forward of the engine room measures 6m by 9m. No.1 hold measures 8m by 8m, as does an area of debris forward of No.1 hold. The preserved part of the bow section measures 1.58m by 1.56m and stands 1.16m proud of the seabed.
 
Fittings and machinery originally located on the deck of the vessel, such as cargo winches and a spare propeller have collapsed and are now sitting upright on the seabed or onthe concreted cargo mounds.
 
While the seabed south of the wreck is fairly sterile, there is a scatter of debris along the port side of the wreck in the North.
 

Fittings and Machinery

Most of the ship's fittings and the machinery lie intact on the seabed. Two anchors, probably both spares, were found on site: Anchor 1 was found leaning against a debris mound forward of No.1 hold. The anchor is missing its stock. A square metal plate is bolted to one of the flukes; it is probably remains of a fastening which secured the spare anchor on deck.
 
AnchorAnchor The second anchor on site was found half buried beneath a steam winch (winch 1) forward of No.1 hold. The folding stock is still attached and folded in. Shank and stock length could not be determined.
 
Smaller in size than anchor 1, this would have been another spare anchor stowed on deck.
 
The anchor windlass was found upright on the seabed 6m forward of No.1 hold. It is 2.95m long and has two warping ends, each 30cm in diameter and 30cm long. Accurate measurements of the windlass were difficult to obtain due to the amount of concretion. Two heavily concreted anchor chains are still attached to the windlass.
 
Further aft on the wreck, three steam cargo winches were observed. The first winch (1) is situated forward of No.1 hold (view image). The second winch (2) is buried underneath iron ore cargo just to starboard of the first winch. Very little of it is exposed and it could not be recorded in detail. The third winch (3) is lying on top of a concreted cargo mound in the stern of the vessel.
 
Steam DrumSteam Drum The remains of the engine room form the most well preserved part of the vessel. The main single ended scotch boiler stands upright on the seabed with a slight list to port. It is 3m in diameter and 3.18m long (view image). The boiler shell is made from riveted steel or iron plates. Stay nuts and firetubes are clearly visible. A 44cm wide opening on top of the boiler marks the original position of the steam drum. A triangular arrangement of three furnace fronts was recorded on the forward face of the boiler.
 
The steam drum has fallen off the top of the boiler and is now leaning against the port side. It is 2.45m long and 1.15m in diameter. The inside of the drum is visible through a large hole. The original attachment opening measures 44cm in diameter and matches the opening on top of the scotch boiler.
 
A large hole in the side of the boiler allows the fire tubes to be seenA large hole in the side of the boiler allows the fire tubes to be seen Forward of the scotch boiler a donkey boiler has collapsed onto its side. It is 3.53m long and 1.85m in diameter. The bottom end of the boiler is still attached to a heavily eroded square base plate. On the top end the 40cm long funnel attachment is visible. The funnel was 40cm in diameter. A large hole in the side of the boiler allows the fire tubes to be seen.
 
The two cylinder compound steam engine is situated just aft of the main scotch boiler (image 1, image 2). The engine is very well preserved with little marine growth. It stands 3.36m proud of the seabed. The engine casing is 2.6m long and 1.27m wide. Two cylinders are visible on top of the engine. The low pressure cylinder is 1.17m in diameter. It has an 18cm wide escape valve arrangement in the centre. The high pressure cylinder measures 91cm in diameter. The escape valve arrangement is 24cm wide. A two door condenser was seen on the aft end of the engine. All engine internals such as connecting rods and crankshaft are well preserved.
 
Around the engine a number of features on the seabed probably relate to the engine room, but could not be identified. A possible pump was observed to starboard of the engine casing. On the port side a spindle wheel is attached to a mount.
 
A spare propeller and crankshaft are lying on the cargo mound aft of the engine room. The crankshaft is 3.65m long. At one end it has a flange of 55cm diameter. The diameter of the shaft is 22cm. The cast iron four bladed spare propeller is lying at an angle on the starboard side of the cargo mound.
 
At the stern of the vessel, the main cast iron propeller is still attached to the propeller shaft.At the stern of the vessel, the main cast iron propeller is still attached to the propeller shaft. At the stern of the vessel, the main cast iron propeller is still attached to the propeller shaft. It has the same dimensions as the spare propeller. The propeller shaft is exposed for ca. 8m before it disappears into the 1.1m wide tunnel. The shaft is 24cm in diameter. The stuffing box, intermediate shaft and two couplings are visible (view image).
 

The cargo

The vessel sank with a cargo of copper, tin and iron ore. On the seabed, the position of individual cargo holds is marked by concreted mounds of iron ore. No copper or tin were observed during the diver and Remotely Operated Vehicle surveys.
 
The United Kingdom Hydrographic Office wreck index mentions evidence of earlier diver salvage . It seems likely that the valuable copper and tin ore was lifted at some point after the sinking. The less valuable iron ore seems to have been left on the seabed.
 

Artefacts

Buried fly wheel.Buried fly wheel. Very few small objects or artefacts were noted on the wreck site. Forward of No.3 hold on the starboard side of the vessel a metal wheel with straight spokes was found. This could have been part of cargo handling machinery or a fly wheel for a pump. A possible large block was observed on the starboard side forward of the main boiler. A smaller fly wheel with curved spokes is located between anchor windlass and No.1 hold.
 

What is the Ore wreck?

In 2003 the ore wreck was identified as the Belgian steamer Concha by Wessex Archaeology on the basis of geophysical data and documentary research. Basic information on vessel dimension and equipment were obtained from Lloyds Register. No further published information on the Concha was found to be available.
 
 
The Concha was a well decked steamer of 883 tons, built in 1877 by the Société Anonyme des Etablissements John Cockerill in Hoboken. She measured 64.98m x 8.32m x 5.09m and was equipped with a two cylinder compound steam engine. The Société Anonyme des Etablissements John Cockerill was the most influential Belgian industrial corporation of the time. It owned coal and iron mines, steelworks and a shipyard in Belgium, Luxemburg, Alsace-Lorraine and Spain. The Concha was built on the corporation yard in Hoboken and operated by the Cockerill Shipping line to transport ore. The Cockerill corporation was founded in 1817. The corporate shipyard started operations in 1824 in Antwerp. It was later moved to Hoboken, where it existed until 1982.
The Concha sank on 20th August 1897 after a collision with the Liverpool registered steam ship Saint Filians.
 
The general vessel layout of the Concha can be reconstructed from the dimensions listed in Lloyds Register. However, the information gathered during the 2005 fieldwork session allows a more accurate reconstruction of the vessel layout. The vessel outline and superstructure are based on typical designs for the period. The internal layout and the position of deck machinery are based on measurements from the geophysical data and diver observations.
 

Videos

Click the links below to see underwater videos from the wreck. You will need QuickTime 6 or above to view them. If you do not have quicktime, please visit the QuickTime website to download the latest version:
  • Bow section of wreck 5004, the Concha (watch video: 6 seconds, 440Kb)
  • ROV footage of the 2 cylinder steam engine on site 5004 (watch video: 33 seconds, 2.1Mb)
  • Cargo winch on site 5004 (watch video: 20 seconds, 1.3Mb)
  • ROV footage of the whole site (watch video: 9mins 37secs, 35.5Mb)

The Gun Wreck (Site 5005)

2987

Location
Site 5005 is located 5.5nm south of Hastings, just to the east of Hastings Shingle Bank. The wreck position is 50.77060N, 00.64781E (Geodetic co-ordinates, WGS 84) or E 334106.41, N 5626992.71 (UTM Zone 31N, WGS 84). The wreck lies at a general depth of 22m (CD). Depths experienced on site ranged from 29m to 30m. What is left on the seabed?
 
The wreck is lying on even keel with a list to starboard and is orientated WNW-ESE. The bow is in the West. The wreck site including debris is 100m long and 18m wide. The vessel stern is intact with a fully preserved poop which stands 9m proud of the seabed. There is a gun on the poop which gave the vessel its name. The aft part of the main deck is also preserved and exposed. The midship area and bow of the wreck are partially or completely buried by sand. Very few structural remains seem to be preserved in the bow area, but a very broken up anchor windlass was observed.
 
Portions of the deck and the top of two boilers were visible amidships. This indicates that the engine room area is completely buried.
 

Fittings and Machinery

On the poop most of the original wooden deck planking is still in place.On the poop most of the original wooden deck planking is still in place. As the wreck was only surveyed by Remotely Operated Vehicle, none of the features recorded on the seabed could be measured. The stern is best preserved. The main propeller is still attached, but two of the four original blades have broken off. The rudder is missing, but parts of the tiller mechanism are still in place.
 
On the poop most of the original wooden deck planking is still in place. Four sets of bitts are situated around the intact emergency steering wheel (image 1, 2, 3). Forward of the wheel a cabin skylight and a mount for a small gun were seen. The gun has fallen off its mound and is lying on the starboard side of the deck (image 1, 2).
 
Forward of the gun mount, a steam driven winch is situated in the centre of the quarterdeck (view image). Two wire reels were seen either side of the winch (view image).
 
A large four bladed spare propeller is secured to the upper deck forward of the collapsed mast.A large four bladed spare propeller is secured to the upper deck forward of the collapsed mast. Parts of a mast or derrick have collapsed onto the main deck just below the poop (view image). In this area, the main deck is intact bar the deck planking which was probably wooden. A large four bladed spare propeller is secured to the upper deck forward of the collapsed mast.
 
Forward of the propeller the hatch for the aftmost cargo hold is visible. The aft hold is separated from the midship area by a bulkhead. A steam winch lies collapsed just forward of the bulkhead (view image).
 
The whole midship area of the vessel is buried, but a large amount of unrecognisable debris was observed on the surrounding seabed, possibly a consequence of the torpedo explosion that led to the sinking of the vessel. The top edges of two scotch boilers, covered by bent and collapsed upper deck structure, were observed amidships (image 1, 2).
 
Debris and the barely visible line of starboard side frames leads towards the bow of the vessel. The bow itself is heavily damaged. The only recognisable features among the debris in this area were a broken up anchor windlass and bitts.
 

What is the Gun wreck?

Site 5005 is listed in the United Kingdom Hydrographic Office wreck index as steamer Umba (No. 20549). This identification is supported by The Shipwreck Index of the British Isles and the book World War One Channel Wrecks. Details on vessel specifications and history were obtained from Lloyds Register and the Schiffsregister der Neptunwerft . A plan of the vessel was published in the maritime journal Strandgut.
 
Recon 5005Recon 5005
 
The Umba was built as Adelheid Menzell (Construction No. 287) in 1903 at the Neptun shipyard in Rostock, Germany. She was a schooner rigged screw steamer with a gross tonnage of 1501t, and measured 88.39m x 12.5m x 5.8m. She was equipped with a triple expansion steam engine delivering 180HP and two boilers. She had a crew of 25 and was capable of a maximum speed of 9kn.
 
According to Lloyds Register in 1917, the vessel had a single deck, deep framing and was equipped with electric light and wireless. The Register also gives the lengths for poop (8.53m), bridge deck (38.1m) and forecastle (10.36m).
 
From 1903 to 1906 Adelheid Menzell was employed on the Hamburg- China route. In 1906 the vessel was bought by the Hamburg Bremer Afrika Linie AG, and was used in the Africa trade. In 1907 she was renamed to Irmgard, renamed again to Utgard and purchased by the Deutsche Seeverkehrs A.G. in Nordenham in 1912. A plan published in Strandgut 17 shows the general layout of the Utgard and her sister ships. A photograph shows one of the sister ships, the Asgard, also built by the Neptun shipyard in 1903 moored in Wilhelmshaven in 1919.
 
In 1914 F.W. Fischer from Rostock bought the Utgard, but shortly thereafter she was commandeered by the Russian forces in Kovda in 1914, renamed to Umba and used by the Archangelsk Murmansk S.N. Co. Archangelsk. The vessel was armed with a single Russian 6pdr gun mounted at the stern. In 1917 the Umba was in turn confiscated by the Shipping Controller in England. In 1918 she was bought by the Ellerman's Wilson Line. She was torpedoed on 30 April 1918 while in ballast en route from Dunkirk in France to Barry Roads in south Wales. The torpedo, fired by SM UB-57, hit the Umba amidships and tore a massive hole into her side. She sank almost immediately with the loss of 20 of her crew of 25.
 

Videos

Get QuicktimeClick the links below to see underwater videos from the wreck. You will need QuickTime 6 or above to view them. If you do not have quicktime, please visit the QuickTime website to download the latest version:

The 1906 Wreck (Site 5009)

Click the red labels on the image below to see underwater photographs. Scroll down to read about the wreck and to the bottom of the page to see videos from the wreck.
 
 

Plan of wreck 5009Anchors Mast hole Winch 1 Winch 2 Portholes Hatch Engine Safety valve Winch 3 Condenser Boiler 1 Boiler 2 Rudder and propeller

Location

Wreck site 5009 is situated 5.56 nautical miles off Beachy Head in East Sussex, just south of the Royal Sovereign Shoals. The wreck position is 50.41.033 N, 00.22.967E (Geodetic co-ordinates, WGS 84) or E 315009.34, N 5618060.89 (UTM Zone 31N, WGS 84). The wreck lies at a general depth of 15.2m (CD). Depths experienced on site ranged from 23m to 30m.
 

What is left on the seabed?

The wreck is lying on even keel in southwest - northeast orientation. The stern in the southwest stands 4.5m proud of the seabed and forms the highest part of the wreck. The site measures 75m x 30m including the debris field. The wreck itself measures 66m x 8m.
 
The aft part of the vessel from the rudder at the stern to the two scotch boilers in the engine room is the best preserved section of the vessel. Internal framing and outer hull plating survive to a level of 2-3m above the seabed.
 
The intact propeller tunnel runs from the 3m high steam engine to the stern. Engine and boilers are well preserved. Forward of the engine room the upper deck has collapsed onto the hull of the vessel with fittings and machinery still attached in their original positions.
 
The vessel sides have collapsed outwards.The vessel sides have collapsed outwards. The vessel sides have collapsed outwards and are now lying facing upwards on the seabed. In some areas portholes are still visible in the sides. The bow is heavily damaged and not recognisable. The bow area is covered in metal debris. Sand levels in the bow and midship area are high and parts of the wreck in these areas are partially or fully buried. Debris scatters were observed on both sides of the vessel and in the bow area. Little debris was seen around the stern.
 

Fittings and Machinery

Common anchors with iron folding stocksCommon anchors with iron folding stocks Even though the upper deck of wreck 5009 has collapsed, machinery and fittings are fairly well preserved. Two anchors with folding stocks, probably a large and small kedge, were observed next to the forward edge of the fore cargo hatch on the upper deck. Both are common anchors with iron folding stocks. They are stored with the stocks folded down, the smaller anchor on top of the larger one.
 
Parts of an anchor windlass were noted beneath metal debris in the bow area of the vessel. Close to the anchors, 1m long bitts marked the side of the vessel (view image). A wire reel with concreted wire was observed on the seabed between the bitts and anchors (view image).
 
Aft of the fore cargo hatch and the mast partner plate (view image) a steam winch is fastened in the centre of the upper deck. It is well preserved but covered in marine growth (image 1, 2).
 
The winch is partly buried and heavily overgrown, but seems to be well preservedThe winch is partly buried and heavily overgrown, but seems to be well preserved A second, slightly larger steam cargo winch is situated 4m further aft. The winch is partly buried and heavily overgrown, but seems to be well preserved.
 
A third winch has collapsed onto the tunnel in the stern of the vessel. It is lying upside down, covered by its baseplate and could not be recorded other than photographically (view image).
 
Two scotch boilers and the two cylinder steam engine are the main components preserved in the engine room area. The boilers are 3m long and have a diameter of 3m. The boiler fronts are partially covered with debris and sediment, but stay nuts and fire tubes can be recognised (view image). The boiler shells are made from riveted iron plates. A steam drum with safety valve is attached on top of the starboard boiler (view image). The steam drum on the port side boiler is missing, but the two attachment holes can clearly be seen (view image). A lifting arrangement with lifting eyes and strops was observed on the portside boiler.
 
A number of pipes have collapsed around and between the two boilers. Some of those probably connected the boilers to the engine. The two cylinder steam engine is well preserved but covered in debris and heavily overgrown. The engine casing is 3.2m long and 1.3m wide. The diameter of the HP cylinder is 1.1m; the LP cylinder is 1.3m in diameter.
 
A number of hatches were observed among pipes and unrecognisable metal objects.A number of hatches were observed among pipes and unrecognisable metal objects. A feature connected to the engine on the port side is thought to be the condenser. It is approximately 2m high and 1.3m in diameter (image 1, 2). The whole engine room area is covered in debris. A number of hatches were observed among pipes and unrecognisable metal objects. A pump was seen on the starboard side of the engine (view image). Aft of the engine, the propeller shaft disappears in the tunnel.
 
The main propeller is still attached at the stern. It has four blades, each 1.45m long and 77cm wide at the widest point. The boss has a diameter of 36cm. A spare propeller is located between the two cargo winches. It is partially buried, but one of the blades could be recorded. The blade is 1.39m long and 80cm wide at the widest point. The rudder is still attached to the sternpost of the vessel. The internal plating has corroded away, but the rudder frame and attachment are intact. The lower part of the rudder is buried in sediment (view image).
 

What is the 1906?

The Shipwreck Index of the British Isles and the Board of Trade Wreck Returns record that a vessel was lost at this position in 1906. Only one vessel with approximately the same dimensions has been identified in the Lloyds Register; the Swedish steamer Talis. It seems likely that the 1906 Wreck is the wreck of the Talis.
 
 
The Talis was built as the Dudley by F & W Smith in North Shields in 1865 as an iron screw steamer of 870t gross. In 1870 the Dudley received a two cylinder compound engine. In 1871 she was lengthened to measure 66.42m x 8.59m x 4.63m. The vessel received new boilers in 1878. In 1885 the Dudley was the first ship bought by Walter Runciman, a young entrepreneur who founded the Runciman Co. and the South Shields S.S. Co. She had been laid up on the Tyne when Runciman found her. The fairly old and small steamer was mainly used in the home trades between Trondheim in Norway and Ipswich on the east coast.
 
Shortly before her sinking the Dudley was bought by Ångfartygs Aktiebolaget Göteborg and renamed Talis. She sank in a collision with the Liverpool steamship Roman on the 22 July 1906 when en route from Llanelli in south Wales to Gävle in Sweden with a cargo of coal.
 
Based on diver observations, geophysical data and documentary sources a reconstruction of the Talis as she would have looked in 1906 has been attempted. The vessel had a very short forecastle (5.79m). No.1 hold was situated between the mainmast and the forecastle. Two steam cargo winches were fastened on the upper deck aft of the mainmast between the two fore cargo holds. The 14.32m long bridge deck was located just forward of the engine room. Another steam winch and thus possibly another mast were located on the 17.67m long poop. The existence of an aft hold is very likely. Walter Runciman was one of the first ship owners to abolish square yards and sails on his ships. Because of this the Talis is depicted with short masts and without sails.
 

Videos

Click the links below to see underwater videos from the wreck. You will need QuickTime 6 or above to view them. If you do not have quicktime, please visit the QuickTime website to download the latest version.
 

 

The Bottle Wreck (Site 5013)

Click the red labels on the image below to see underwater photographs. Scroll down to read about the wreck and to the bottom of the page to see videos from the wreck.
 
 

Plan of the Bottle wreckPipes 1 Pump box Copper sheathing Pipes 2 Anchor Hull structure Pipes 3

Location

Wreck site 5013 lies 7.18 nautical miles east south east of Selsey Bill. The wreck position is 50.40.919 N, 00.36.557W (Geodetic co-ordinates, WGS 84) or E 668864.22, N 5617198.10 (UTM Zone 30N, WGS 84). The wreck lies in a general depth of 19.7m (CD). Depths experienced on site ranged from 22m to 26m.

What is left on the seabed?

The pipe cargo mound is 11.5m long and measures 6m across.The pipe cargo mound is 11.5m long and measures 6m across.The wreck is lying on an even keel with a slight list to port orientated NNE - SSW. The site is 28m long and 8m wide. The most prominent feature on the seabed is the cargo of stacked iron pipes which ranges from 60cm to 2m in height. The pipe cargo mound is 11.5m long and measures 6m across (view image).
 
In an area 4m to the South of the pipe cargo, partly exposed hull timbers mark the location of the bow. To the North buried timber and copper bolts are visible in a distance of up to 10m from the cargo mound. The pipe cargo mound has partly collapsed to the starboard side, where broken pipes and metal debris are lying on the seabed.
 
Scattered artefacts and concretions are exposed on the seabed in an area of c. 30m around the wreck. A concentration of glass beer bottles and bottle shards was observed in the bow area. North of the cargo mound the seabed is littered with broken pottery and potsherds. Two large irregular shaped lumps of a brown, possibly organic material were observed in the bow area, covering some of the exposed hull structure. The nature of this material is unknown.
 

Construction

The lower part of the vessel’s hull survives in the seabed. Timbers are exposed in the bow area and close to the stern only. Due to the level of burial, excavation would be necessary to allow more detailed recording of the structural remains.
 
Outer planks are 6-8cm thick and ceiling planks have a thickness of 5cm.Outer planks are 6-8cm thick and ceiling planks have a thickness of 5cm.The vessel seems to be built from oak. Outer Planks and ceiling planks are fastened by a combination of trenails and copper drift or clench bolts. In the bow area frames are 16cm to 19cm sided and 18cm moulded. Outer planks are 6-8cm thick and ceiling planks have a thickness of 5cm. In one area the width of a ceiling plank could be measured as 30cm. All trenails have a diameter of 3.2cm. The average diameter of the copper bolts is 2.5cm (view image 1, 2).
 
The outer hull is copper sheathed. Small pieces of copper sheathing were found around the wreck and copper sheathing was still attached to an outer plank in the northeast of the site (view image). In the bow area cant frames curve inwards towards the stem post, but the exact position of the post cannot be determined due to the sediment levels on the site.
 
During an excavation of the bow area in 1983, divers of the Chelmsford Underwater Archaeological Unit uncovered the keelson (the upper part of the keel), which was 25cm wide and 23cm high. Just south of the pipe cargo, a mortise measuring 15cm x 15cm was observed in either the keelson or a 5cm high mast step on top of the keelson. The foot of the fore mast would have been stepped into the mortise. The mast step was covered by a round concretion 61cm high and 35cm in diameter, possibly the remains of the fore mast.
 
A second mast step, covered by concretion, was observed just forward of a pump box in the pipe cargo mound in 2005. Measurements could not be obtained as the pipes shifted sternwards onto the pump box and covered the mast step. Its association with the ship's pumps would suggest that this was the position of the main mast.
 
At the stern a single timber was seen 8m aft of the pipe cargo mound in line with the lubber line of the vessel. It is heavily eroded and measures 2m by 50cm. Three eroded copper bolts extend upwards from the timber. Judging by its location, this could be part of keel, keelson or part of the stern construction of the vessel.
 

Fittings

An iron pump boxAn iron pump boxVery few fittings are preserved on the seabed. The shaft, stock and ring of a small anchor were observed in the bow area on the portside of the vessel (view image 1, 2). The iron stock is 4cm in diameter and 1.3m long. The ring has an outer diameter of 20cm. The inner diameter is 12cm. The shaft is heavily concreted and barely visible. Crown and arms are buried.
 
An iron pump box, measuring 1m x 40cm is located aft of the mainmast in the pipe cargo mound. The concreted remains of two metal suction pipes, each of 18cm diameter are visible in the box.

Cargo

Several different types of cargo are known to derive from site 5013. The cargo can be divided into the following categories:
  • Cast iron pipes
  • Beer (in barrels and bottles)
  • General Cargo (including pottery, cutlery, razors and guns)

 

Cast iron pipes

Lengths of Cast Iron PipesLengths of Cast Iron PipesLengths or 'sticks' of cast iron pipes form the main cargo mound which is clearly visible on the seabed. In 1983 divers counted 204 pipes in four banks. The sticks are 2.77m (9ft) long with a 10cm (4in) socket at one end. The external socket diameter is 38cm (15in). External pipe diameter is 30cm (12in). The internal diameter is between 17cm and 18cm (7in).
 
Type and diameter of the pipe sticks suggests that they were designed as water or drainage pipes. Cast iron water pipes were first used in the late 17th century and became increasingly popular in England and the United States from the beginning of the 19th century. In the United States cast iron pipe production started in 1819. Before this date and to a certain degree even afterwards, cast iron pipe was imported from England or Scotland.
 
The spigot and socket type pipe joint was developed by Sir Thomas Simpson in 1785. This joint is typical for cast iron water pipes. The pipe sticks were pushed together, and the joints were caulked with lead.
 
The Encyclopaedia for Municipal and Sanitary Engineering lists typical drainage pipe diameters with associated metal thickness and pipe weight. Water pipes are usually measured by the outer diameter. According to the Encyclopaedia, the 12in pipes found on site 5013 would have been made from 9/16in or 1.4cm thick metal. A pipe stick would have weighed 8.5cwt or 431kg.
 

Beer

Beer bottles and barrels were found forward of the pipe cargo mound. At least two barrels were excavated in 1983. The barrel staves are 1.07m (42in) long and the words 'BARCLAY & PERKINS' are burnt into the lids of the barrels. The barrels were probably hogsheads and would have contained 54 gallons of ale or porter. The Barclay & Perkins brewery was founded in Southwark, London in 1781 and was the biggest producer and exporter of beer in the 19th century.
 
Broken beer bottles are scattered on the seabed all around the bow area, forward of the pipe cargo. In 1983 around 500 complete and corked bottles were lifted from the site. The bottles are all of the typical 'porter' shape, common between 1760 and 1918. They are ½ pint in size. Some of the bottle corks were inscribed 'Kinnley Williams London'. Brewers of this name could not yet be tracked down. The bottles contained porter, which was a very dark and malty type of ale based on roasted malt. Porter became popular at the beginning of the 18th century and was known as a working class beer. English porter was exported to a number of countries, among others the United States, Australia and India.
 
Samples of yeast preserved in some of the corked bottles lifted from the site were used to recreate the original beer in 1991. The result is sold as Flag Porter by the Darwin Brewery, UK.
 

Pottery

The pottery on site 5013 is concentrated in the area aft of the pipe cargo mound.The pottery on site 5013 is concentrated in the area aft of the pipe cargo mound. The pottery on site 5013 is concentrated in the area aft of the pipe cargo mound. Five different types of pottery can be distinguished:
  • Blue and white transfer printed willow pattern plates
  • Pink, blue and black transfer printed ware, unknown pattern with romantic landscape
  • Dark brown transfer printed ware, Bombay Japan pattern
  • Annular ware, mocha pattern
  • Refined whiteware, plain
Several blue and white transfer printed willow pattern plates were found on the site. Some examples are also kept in Littlehampton Museum. One plate was lifted, photographed and drawn in 2005. The plate has a diameter of 24.5cm and the bottom is marked 'R&C'. This trade mark could be identified as belonging to the pottery Read & Clementson which was based in Hanley, Staffordshire between 1833 and 1835.
 

Cutlery

In the 1980s unknown quantities of cutlery including spoons, knives and forks were lifted from the site. No complete examples of the knives or forks could be recorded, but a number of spoons and bone knife handles are preserved in Littlehampton Museum. The spoons are of the fiddle pattern, typical of the early 19th century.
 

Further General Cargo

Further general cargo found on the site includes gun flints and flintlocks, glass salt cellars, silver sugar tongs and a number of cutthroat razors. The bone razor handles were engraved with a number of different motives, including portraits of George Washington, the Liberty Bell and rural farming scenes. A razor handle recorded in Littlehampton Museum was engraved with a horizontal wave pattern.
 

What is the pipe wreck?

The archaeological evidence gathered during the 2005 field session indicates that wreck 5013 is the remains of a wooden merchant sailing vessel. Judging by the extent of the site and the preserved hull timbers, the vessel was ca. 28m (91.8ft) long and had a breadth of 7-8m (23ft-26ft).
 
 
It had at least two, possibly three masts. The foremast was situated 4m aft of the stem post. The distance between foremast and mainmast was 9m. The ship was carvel built from oak and fastened with trenails and copper alloy bolts. The outer hull was copper sheathed.
 
The ship's bilge pumps, situated aft of the main mast had cast iron tubes. The vessel was carrying a cargo of cast iron pipes, beer and general goods, including pottery. All elements of the cargo date to the first half of the 19th century.
 
The identification of the maker of one of the blue and white transfer printed willow pattern plates allows more accurate dating, as the pottery Read & Clementson only existed between 1833 and 1835. The terminus post quem for the sinking of the vessel is thus 1833. The terminus ante quem could tentatively be defined as 1835, but there is a possibility that Read & Clementson transfer printed ware continued to be traded after the pottery closed down.
 
Wreck 5013 was a wooden merchant vessel with at least two masts. The dimensions of 28m x 7/8m or 91.8ft x 23-26ft would be typical for a brig of 200t to 300t.
 
The copper sheathing indicates that 5013 was intended for trading in warmer waters, either the Mediterranean or the overseas trade. This interpretation is supported by the cargo assemblage found on the site.
 
Cast iron pipes, porter, beer and Staffordshire ceramics would be typical British export goods in the first quarter of the 19th century. Only the ornamented bone razor handles give an indication of the possible destination of the vessel. Designs such as the George Washington portrait and the Liberty Bell would only have been popular in the United States.
 
Altogether wreck 5013 is probably the remains of an English brig of 200t - 300t, trading overseas, possibly to the United States. The vessel sank after 1833 and possibly before or during 1835, although a later date of sinking cannot be ruled out. The visible structural remains do not allow a more detailed description of the construction.
 

Videos

Get Quicktime. Click the links below to see underwater videos from the wreck. You will need QuickTime 6 or above to view them. If you do not have quicktime, please visit the QuickTime website to download the latest version.
 

Methodology Results

Based on the results of Round 1 of 'Wrecks on the Seabed', Round 2 aimed to further develop and test methodologies for the assessment, evaluation and recording of wreck sites. The project objectives related to three different subheadings:
  • Infrastructure
  • Remotely operated vehicles and
  • Intrasite survey.
The Round 2, Year 1 fieldwork was divided into a 15 day ROV session followed by two 15 day diving sessions.
 
Seven study sites were visited during the ROV session. All of these had been subject to geophysical survey, diver investigation or both in Round 1.
 
Each of these sites were to be recorded to level 2a with the aim to develop methodologies for the use of ROVs in underwater archaeology and to integrate ROV based methods with tracking and recording systems. In addition, the use of ROV survey instead of diver-based methods and the use of ROV survey to complement diver-based methods were to be assessed.
 
The two diving sessions concentrated on three wreck sites that had been very difficult to access during Round 1 of the project. All three sites were recorded to level 3a or 3b in the course of the diving sessions of Round 2.
 
Round 1 diving was conducted from a small workboat that returned to port every night. In Round 2, MV Flatholm, a 26m converted tug, was used as the diving support vessel. Weather permitting, Flatholm was able to stay out on site for the whole 15 day session with crew and dive team living aboard.
 

Infrastructure

When assessing the effectiveness of a larger platform in maintaining station in prevailing conditions it was found that the larger vessel had clear advantages over the small workboat. The position on site could be held in winds up to force 6Bft. When investigating the scope for increasing working time by coping with less favourable conditions, it was found that downtime could be reduced by 10% through the use of a larger vessel. The larger vessel also enabled work on sites that could not be accessed in Round 1.
 
 
By maintaining station on site whenever possible, travel time was reduced and it became possible to work additional slack water periods. By doing this, the total average bottom time per day could be increased by 60 %.
 
The larger work platform also proved to be beneficial for the use of acoustic tracking systems, although it was difficult to quantify this effect.
 
An assessment of the benefits of a larger platform for accommodating and handling diving and ROV systems showed that the larger vessel had several advantages over the small workboat. Equipment could be stored safely, protected from spray and wash. It was also possible to carry out maintenance on board and undertake post-processing tasks, thereby increasing work efficiency.
 

The use of ROVs in underwater archaeology

It has been possible to develop a methodological approach for level 2a surveys with a remotely operated vehicle. In addition, ROV-based methods were successfully integrated with the USBL tracking system and the Wessex Archaeology diver recording system DIVA.
 
The use of ROV survey instead of diver-based methods and as a complement to diver-based methods was also assessed.
 
It was found that when used as a stand-alone tool, the ROV proved to be an efficient mechanism for the rapid survey of large wreck sites with acceptable visibility. The extent and character of wrecks could be determined, and rough site sketches sufficient for a level 2a survey could be made from the tracked ROV video footage in combination with previously obtained geophysical data. However, it was difficult to understand the layout of individual components as the ROV lacked measuring capabilities.
 
Due to the danger of snagging and losing the vehicle, visibility proved to be an important limiting factor for the use of ROVs on wreck sites.
 
A comparison of deployment costs showed that a small survey class ROV such as the Seaeye 600 used was slightly cheaper per day than a dive team, and that overall work rate was significantly greater for level 2 survey.
 
An idealised scenario would be to use the ROV for the level 2a evaluation and then deploy divers for the more detailed level 3, in situ recording. The time consuming tasks of getting an overview of the wreck and defining its extents could be carried out by the ROV and the divers could concentrate on the detailed recording of selected elements identified during the ROV survey.
 

Intrasite survey

A USBL acoustic positioning system was successfully deployed during diving and ROV sessions. The general positioning accuracy achieved with this system using external sensors in single dives varied between 0.5m and 2m and was sufficient for the tolerances/requirements of a level 2a survey. The issue of low repeatability from dive to dive, attributable to GPS, was avoided by conducting designated positioning dives with the aim of positioning all important elements and datum points on sites in a single dive.
 
The Wessex Archaeology recording system, DIVA, was improved and upgraded to run with ArcGIS 9 rather than Arcpad and to include new features. Altogether the recording system with its seamless integration with the acoustic positioning system was found to facilitate decision making in the field and greatly reduce post-processing times.
 
As part of the objective to develop underwater video and still photographic methods, different camera and lighting systems and settings were tested under a variety of conditions to find the best camera and strobe settings.
 
During the post-processing of photography and video, photo mosaics were derived from digital still photos and video captures. Two different software packages were used. Smoky City Designs Panorama factory was found to work best for panoramic underwater still shots taken by swivelling around a single point. The photomerge function in Adobe Photoshop Elements worked well for stitching video captures into plan view photomosaics.
 
 
As part of the development of underwater video methods, video editing facilities were used on site. After each dive the captured video was reviewed and important clips were stored in a site movie project. This allowed site sketches to be corrected and completed and effectively reduced post processing times.
 
As part of the project, the levels of archaeological recording for level 2 and 3 were refined. Recording tasks and related recording foci were added to each of the levels and sublevels.
Altogether the project has improved the knowledge necessary for specifying and conducting rapid and efficient ROV and diver based wreck surveys in areas with conditions similar to the English Channel Coast.
 
PDF files of the project report with a full discussion of project objectives and results can be downloaded in the project download area.

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