Year 2 (Deep ROV)

In 2006 we applied the Remotely Operated Vehicle (ROV) survey methods that we tested on shallow wrecks last year to deep wreck sites. We wanted to find out whether a detailed archaeological survey of a wreck was possible with a ROV.

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.

Project Aims and Objectives

Aggregates being dredged from increasingly deeper waters. As a result, we need to know if the ROV survey methods tested in shallow waters will work on wrecks in up to 60m of water.
 
Three unexplored wreck sites were chosen to assess ROV methods. The wreckslay in water depths of between 50m and 60m, and had been surveyed with multibeam sonar, sidescan sonar and magnetometer in Round 2, Year One as part of the geophysical section of the current round of the project. The geophysical data from these surveys was used as a basis for the ROV survey.
 
All three sites were subject to an ROV survey aiming at level 2 or 3 recording.
 
This report is divided into two parts. Firstly, a methodological section which discusses the individual deep ROV project objectives. Secondly, the archaeological results of the fieldwork are presented.
 

Project Aim

The aim of the project is to provide industry, regulators and contractors with a framework for the incremental, decision-oriented investigation of wreck sites and with guidance on their archaeological assessment, evaluation and recording.
 
A framework like this is important when considering the cost and time implications marine archaeological investigations.
 
It is also important for developing effective communication between industry, regulators and contractors.
 

Project Objectives

  • Develop and refine methodologies for assessing, evaluating and recording sites in deeper water.
  • Assess the effectiveness of undertaking archaeological recording (to Levels 2 and 3) using ROV and geophysical techniques only.
  • Assess environmental issues (e.g. depth, distance from port, fetch) in respect of working on sites in deeper water.
  • Assess infrastructure issues (e.g. anchoring, tow cable handling, umbilical handling) in respect of working on sites in deeper water.

Methodology

Dummy

Support Vessel

 
We used the Sara Maatje XV , a survey, supply and support ship operated by Van Stee Survey and Supply B.V. of Harlingen in the Netherlands as our diving support vessel. The vessel has a length overall of 36m, a beam of 7m and a 1m draft.
 
Sara Maatje XV is equipped with two 300hp main engines, one 500hp Schottel (directional propeller) and a 120hp bowthruster, which provide excellent manoeuvrability.
 
The vessel has a 136m² wood covered working deck equipped with a hydraulic double drum winch for anchoring and a 80t/mtr deck crane.
 
It provided accommodation for 10 people in five cabins and was equipped with heads, showers, a large messroom and a galley. Water for approximately ten days could be stored in a 13m³ fresh water tank. Three different generators provided 450V AC, 240V AC, 24V DC and 12V DC power supply on board.
 
The Wessex Archaeology ROV equipment was set up in the large survey office in the wheelhouse.

ROV

 
For the survey of the deep wrecks we used a Seaeye Falcon ROV. The ROV and operator were supplied by Subsea Vision Ltd.
 
The Seaeye Falcon measures 1m x 0.5m x 0.6m and weighs 50kg. Four vectored vertical thrusters and a single horizontal thruster provide a maximum forward speed of more than 3 knots.
 
The ROV was fitted with a Tritech Typhoon Zoom video camera, a Tritech Tornado Low Light Monochrome video camera and three 75 watt lights.
 
In addition, a Kongsberg underwater digital stills camera (a Canon Powershot G5 in a Kongsberg housing) with flashgun and a Tritech ISS scaling camera were mounted on an under-slung module for some dives.
 
The ROV was equipped with forward scanning Tritech Mini King sonar for navigation, a built in fluxgate compass and a digital depth gauge. Information from all these instruments could be displayed over the video output.
 
The surface controls consisted of the main ROV surface unit, a hand controller with joystick, a screen, two PCs for sonar display and digital stills camera control and a Sony digital video capture unit. Video was recorded on miniDV tapes.
 
For the wreck surveys we tracked the ROV using an acoustic underwater positioning system.

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.

Scaling Camera

The Tritech Image Scaling System (ISS) can measure the size of objects underwater.
 
 
The system consists of a PAL colour zoom video camera with six lasers. Four of these lasers provide parallel beams. The other two are mounted at predefined angles to provide reference points. To measure an object, a video screen capture has to be taken with the lasers pointed at the object. The screen capture is then imported into the ISS-SOFT package after the dive, where the image can be analysed and measurements can be taken Depending on the image quality and camera angle, objects can be measured to within one millimetre.
 

The Wrecks

Click on the wreck number to view the wreck information

Site map

Unknown B-24 (site WA 1001)

 
After the geophysical survey of WA 1001 it was targeted for the use of the ROV. Originally thought to be the remains of a wooden shipwreck, the site turned out to be the wreck of a Second World War B-24 bomber. Use the menu above to find out more about this wreck. To see what we found on the wreck site click on the red text or related orange parts in the plan.
 
The ROV survey of Wreck WA1001 showed that the site had not been correctly identified from the geophysical surveys. The wreck of the B24 bomber was too broken up with not sufficient structure for it to be positively identified as any sort of aircraft. In retrospect this site differed from other wooden wrecks seen by WA in that there was no evidence of isolated planks lying around the wreck site.

Bomber plan

Site Layout

The geophysical data for site WA 1001 shows two main anomalies. The largest of these which is 25m x 10m. A number of smaller anomalies were detected within of 25m-50m of the main anomaly. Another large anomaly, measuring 6m x 1m lies about 180m to the NE. The resolution of the data is not high enough to discern the exact shape and nature of these anomalies.
 
As a result of the weather conditions and low underwater visibility, only the main anomaly could be dived in the time available. The low visibility made it very difficult to understand the wreck layout. The wreck plan on this webpage only represents the main anomaly.
 
The most prominent features on the site are the remains of four aircraft engines which are still attached to the wings or sections of them.
 
Wing 1 is lying in a NW-SE orientation in the east of the site. The two engines designated Engine 1 and Engine 2 are still attached to the wing and are about 3m apart.
 
The second wing (Wing 2) appears to be less complete. It lies in a NE-SW orientation about 11m to the west of Wing 1. Engine 3 is still attached to the wing, but Engine 4 could not be positioned accurately.
 
The fuselage of the plane has broken up but seems to extend in a W-E orientation just north of the wings. Most of the surviving structure is partially or fully buried. What is visible may have been uncovered recently. This is also suggested by the presence of numerous textiles, including American clothing, on and around the site.
 
No bombs or machine gun ammunition were observed. However, ordnance may be present and the potentially dangerous character of the site should be noted.
 
No human remains have been sighted during the two ROV dives, but the presence of well preserved clothing on the site makes it very likely some or all of the crew were still aboard the plane when it crashed.

Fittings and Machinery

Engine MountingEngine Mounting Most of the wreckage is from the aircraft wings. The centre sections of the port wing and starboard wing are fully preserved and lying upside down on the seabed. Most of the wings are still covered with the aluminium outer skin, though this skin is missing along the leading edges.
 
Engine BlockEngine Block Further wreckage between and to the north of the wing sections could be from the outer wing panels or the fuselage.
 
The four Pratt & Whitney R-1830 Twin Wasp engines are in situ on the wings though their cowlings are missing. The engine mount assemblies are still attached to the rear of the engines. The inboard and outboard engine mount supports have collapsed onto the underside of the wings.
 
The engine blocks with their 14 twin row cylinders are surrounded by the exhaust collector rings. The cylinders are 15cm in diameter.
 
Turbo SuperchargersTurbo Superchargers Each of the engines is associated with a rectangular Harrison or Airsearch flattened tube intercooler. The intercoolers serve to cool the hot compressed air delivered by the superchargers.
 
PropellerPropeller They are situated behind the firewall at the back of each engine. Loose Type B-2 turbosuperchargers were observed on the seabed in the vicinity of Engine 1 and Engine 2. The superchargers were originally located below and at the rear of the engines.
 
A round oil tank was observed to the east of Engine 1.
 
Engine 1 and Engine 2 both have hydromatic propellers. On Engine 1, the propeller is lying upside down with the dome buried in the seabed and the nose section facing upwards. The propeller on Engine 2 is lying upright on the seabed south of the engine with the dome facing west and the nose section facing east.

Artefacts

Leather StrapLeather StrapSeveral pieces of textile were seen in different areas on the site. Some items were half-buried, while others were entangled in and around wreckage. The generally good preservation of the textiles suggests that it was buried until recently.
 
Most of the items on site were difficult to recognise. Strips of olive drab material were observed entangled around fuselage. White fabric, possibly parachute silk was also seen in several areas around the wreckage. A leather strap with buckle attached to olive or khaki fabric was stuck in a piece of aluminium fuselage on Wing 2.
 
To the west of the wreckage, a thin blue fabric with a white floral pattern lay half buried. This could be the remains of either a shirt or a scarf.
 
Snorkel parkaSnorkel parkaThe most diagnostic item on the site was the orange lining of an olive flying parka. This was wrapped around Engine 1. A label attached to the lining is decorated with a floral border and reads “Original Snorkel Parka”.
 
This type of parka was not a standard military issue item during the Second World War, but looks very similar to the standard issue N-3 snorkel parka that was introduced with the formation of the USAF in 1947.
 
The N-3 snorkel parka or heavy flying jacket was based on prototypes tested from 1942- 1945. During the war it was common for military personnel to supplement issued clothing with privately bought items. The snorkel parka on the site could either be a test prototype, although the non-military label makes this less likely, or a private item bought by an airman to keep warm at high altitudes in the unpressurised and unheated aircraft.

Identification

Wreck WA 1001 is the remains of a four-engined aircraft, probably from the Second World War. The clothing recorded on the site suggests that the aircraft was American.
 
The two most common four engine bombers used by the United States Army Airforce (USAAF) during the Second World War were the B-17 Flying Fortress and the B-24 Liberator.
 
Initial research showed that the B-17 ‘My Day’ of the 388th Bomber Group crashed into the sea off the Isle of Wight in 1943. The 388th Bomber Group Association was therefore contacted to find out more about this accident and possibly identify the wreck.
 
Some of the ROV video footage was sent to the Curator of the 388th Bomber Group Collection to verify whether the wreck could be the remains of a B-17. After a first review of the footage, it was concluded that the remains on the seabed were not those of a B-17 bomber, but could be from a B-24 or a British four-engined bomber. Further footage was then sent to the 388th Bomber Group Collection and the RAF Museum in Hendon, both of which confirmed that the remains are of a Consolidated B-24 Liberator, lying upside down.

B-24 History

The development of the B-24 long range bomber was started by a request to the Consolidated Aircraft Corporation to set up a second production line for B-17 bombers in 1938.
 
The Consolidated chief engineer suggested a different design instead, based around a new wing patent that had less drag than the existing B-17 wings.
 
On 30th March 1939 Consolidated received a contract to build the first prototype of the new bomber which was designated the XB-24.
 
Development proceeded quickly and a number of the first production models, called YB-24, were delivered to the RAF in 1940. The B-24D was the first mass produced variant of the Consolidated ‘Liberator’ which was used by the USAAF from 1941.
Altogether 2,738 B-24Ds were built. Wartime development then continued through to model B-24M. Most of the later B-24 models were based on the B-24D, with changes in mainly the armament and equipment, as well as attempts to make the bomber lighter in order to increase its performance.
 
In total, some 19,203 B-24’s of 15 different variants were constructed during the war. Together with the B-17, the B-24 became the most used heavy long range bomber of the Second World War.
 

Technical Specifications

The technical specifications for the B-24D Liberator were:
 
Span
33.52m
Length
20.22m
Height
5.46m
Wing Area
97.36m²
Weight (empty)
15413kg
Weight (max take off)
27216kg
Armament
One (usually three) 0.5-in (12.7-mm) nose gun, two in dorsal turret, two in tail turret, two in retractable ball turret and two in waist positions; plus a maximum internal bomb load of 8,000 lb (3629 kg)
Powerplant
Four 1200 hp Pratt & Whitney R-1830-43 Twin Wasp radial piston engines
Max. Speed
488km/h
Range (5,000lb bomb load)
1730km
Crew
10

 

B-24 Liberator bombers in Europe

The first Liberators to enter the European war theatre were the YB-24s, which were also called Mark I models, which were delivered to Britain in March 1941.
 
These aircraft were used for Atlantic transport duties, and later for long range anti-submarine patrols in the Battle of the Atlantic by RAF Coastal Command. Mark II models delivered later in 1941 were also used by the RAF Bomber Command. The first bombing raids employing Liberator Mark II’s were carried out by RAF squadrons in the Middle East.
 
After the United States declared war on Germany and Italy on 11th December 1941, the USAAF entered combat on 11 June, 1942 with an attack on the Romanian oilfields at Ploieşti, carried out by 13 B-24 Liberators.
 
In August 1942 the first strategic bombing raids on Germany were carried out by units of the 8th Airforce from British airfields. The so-called Combined Bomber Offensive, which started in June 1943, involved massive bombing of German occupied areas and plants and factories in Germany by the RAF and the USAAF.

Media

Unknown Steamer (WA 1002)

 
After the geophysical survey of WA 1002, the site was targeted for survey by ROV. The wreck is an unidentified steamer, thought to have sunk during the First World War. Use the menu above to find out more about this wreck. To see what we found on the wreck site click on the red letters or related orange parts in the plan.
 
The interpretations of Wreck WA1002 from the geophysical and ROV surveys were broadly in agreement with the dimensions of the wreck and the damage to the hull, identified from the geophysics data, were confirmed by the ROV survey. The lack of detail seen in the sidescan sonar data due to the wreck lying on its side could not be compensated for during the ROV survey as conditions prevented the ROV operating on the NW side of the wreck.

Ship Plan

Site Layout

The wreck is lying on its starboard side with its bow facing SW. The vessel is about 63m long but as the stern area seems to be damaged it could have been longer.
 
The beam is c. 8-10m and the depth in hold c. 5-6m. The ship does not seem to have broken up. Outlying debris is visible only in an area just off the stern in the NE.
 
No superstructure is preserved, but the upper deck structure seems intact and a number of deck fittings were observed. The upper deck is vertical and facing NW. At least two cargo hatches are visible. The hull appears to be fairly intact with the exception of a large area of damage on the port side 20m from the stern. Here a 6m x 6m hole was seen in the side of the vessel.
 
In addition to the possible damage to the stern, the metal at the edge of the hole in the hull is bent inwards, suggesting an impact from the outside.
 
Due to strong currents and low visibility it was not possible to explore the seabed on the NW side of the shipwreck. The intact upper deck prevented access to the inside of the vessel, so it was not possible to see any internal machinery, cargo, or ballast.

Construction

Riveted PlatingRiveted PlatingAs most areas were covered by dense marine growth little can be said about the construction of the vessel beyond that it was built from riveted iron or steel plates.
 
One section of hull plating could be surveyed in more detail. This was fastened by two/three rows of 30mm rivets. It was not possible to obtain measurements of the hull plates themselves, the frames or the beams.

Fittings and Machinery

Anchor flukeAnchor flukeEven though the hull is almost intact, only a few fittings could be observed and recorded on site WA 1002 due to the dense cover of marine growth and the very low visibility.
 
At the bow, a Hall’s patent stockless anchor was observed secured in the hawsehole. One of the anchor flukes was measured with the ISS scaling camera as being 48cm long and 24cm wide. The distance between the flukes is 42cm.
 
Anchor ChainAnchor ChainOn the now vertical foredeck, an anchor windlass is still secured to the deck. It is heavily concreted but a 6cm wide spur wheel and the 7cm wide brake could be seen. Chain runs from the windlass towards the hawsers. An individual chain link was measured as being 23cm long and 6cm wide.
 
BollardsBollardsA 5cm wide iron fitting with a block was attached to the side of the foredeck. This could have been part of the rigging or a davit.
 
Further aft towards midships, two fairleads were observed. Both have an overall length of 65cm and are 22cm wide. The first is situated just aft of the foredeck. The second fairlead is located just aft of midships. It is associated with a set of bollards which measure 32cm across.

An attempt to identify the wreck

Only limited archaeological evidence could be collected during the survey. However, we know that the wreck is of remains of a riveted iron or steel steam or sailing vessel which was built at the end of the 19th or the beginning of the 20th century. Hall’s patent stockless anchor was first used in 1886.
 
The general vessel dimensions are: LOA (length over all) 63m, BOA (breadth over all) 8-10m and D (depth in hold) around 5-6m.
 
Although difficult to determine from the available evidence, the general hull shape suggests a steamship rather than a sailing vessel.
 
The extensive damage to the hull amidships on the port side suggests how the vessel was lost. The hull is bent inward in this area, suggesting an impact perhaps caused by a shell, torpedo, or a collision with another ship.
 
Because only limited archaeological evidence is available, the only possible approach to identifying the WA 1002 was to search lists of lost vessels for the general area, such as Richard Larn’s Shipwreck Index. Any vessels that match the dimensions and date of the wreck can then be checked against the United Kingdom Hydrographic Office (UKHO) shipwreck database to see whether they have been identified. Dive guides and the National Monuments Record (NMR) can be also checked.
 
This process only leaves a few candidates.
 
The Hall’s patent anchor shows that the ship sank after 1885. As the loss is not recorded, it is seems likely that the vessel sank in either of the two World Wars. In these wars the amount of shipping being sunk made the keeping of accurate records very difficult.
 
The following vessels have been identified as possible candidates for WA 1002:
 
Vessel Name
Vessel type
Vessel dimensions (m)
Date of sinking
Recorded Sinking Location/ Position
Peter der Grosse
Steamship
LBD 60.65 x 8.65 x 6.33
03/ 1893
Beachy Head Offshore, not known
Gotthard
Steamship
LBD 73.24 x 10.72 x 6.22
03.09.1916
Beachy Head Offshore, 45nm or 25nm SW
Polpedn
Steamship
LBD 78.57 x 11.06 x 5.15
14.11.1916
Littlehampton Offshore, 20nm S, 50.27.30N, 00.30W
Houlgate
Steamship
LBD ?, 929t net
22.11.1916
Beachy Head Offshore, 24nm WSW?

 

The Peter der Grosse

The Russian steamship Peter der Grosse sank following a collision with the German Preussen on the way from Hamburg, Germany, to Greenock in Scotland. The vessel was registered in St Petersburg and owned by the St. Petersburg Dampfschiff Gesellschaft (Steamship Company).
 
The ship was built in Germany in 1872 by the Norddeutsche Schiffbau Aktiengesellschaft in Kiel. The iron steamship was equipped with two boilers and a two cylinder compound steam engine. No further details about the position of the collision with the Preussen could be found.
 

The Gotthard

The Norwegian steamer Gotthard was torpedoed by UB-25 en route from Middlesbrough, England to Rouen in France with a cargo of cast iron pigs and sulphate. The Gotthard was built in Christiania, Denmark, in 1906. She had a single boiler and a three cylinder triple expansion steam engine.
 
Two different positions of sinking are recorded for the Gotthard. The English position would put the wreck much further to the South than WA 1002. However, the position given in the Norwegian sources would put the wreck in approximately the right area. The Gotthard is 10m longer than the length of WA 1002 measured on the multibeam data, but this difference could be explained by the apparent damage to the stern area.
 

The Polpedn

The Polpedn, a steel steamer owned by Farrar, Groves & Co Ltd., London, was sailing in ballast from Dunkirk in France to Ayr, Scotland when she was attacked by UB-38. The vessel was torpedoed amidships on the port side and sank within five minutes.
 
The Polpedn was an Admiralty prize (ex Thor), equipped with a three cylinder triple expansion steam engine and a single boiler. Although the recorded sinking position is a fair distance from the position of WA 1002, this might be explained by inaccurate positioning due to the rush in which the crew abandoned ship.
 
As with the Gotthard, a difference in length between the Polpedn and WA 1002 could be due to the damaged stern on WA 1002. The damaged midship section observed on the wreck would be consistent with the torpedo damage sustained by the Polpedn.
 

The Houlgate

The Houlgate was a Canadian steamer of 929 tons net, owned by a French company at the time of sinking. The vessel was en route from Montreal, Canada to Le Havre, France, with a cargo of coal, when she was shelled by a German submarine.
 
There are conflicting reports. The crew abandoned ship and watched it sink after an explosion in the boiler room. However, a British patrol ship reported finding the Houlgate deserted the next morning but it sank shortly afterwards. The vessel dimensions are given as 73m x 12m x 4.5m.
 
It is difficult to narrow down the search any further and securely identify wreck WA 1002 without additional archaeological evidence. All four of the vessels could, in terms of their size and date, be matched with WA 1002 and all are reported to have sunk in the approximate area of WA 1002. In addition, all were subject to damage of some sort, which could be consistent with the damage observed on the wreck.

Media

U-86 (site WA 1003)

 
After the geophysical survey of WA 1003 the site was targeted for ROV survey. This site, previously listed as unknown, proved to be the wreck of a First World War German U-boat. During the survey it was identified as U-86. Click on red text for photographs of wreck.
 
The sidescan sonar data for Wreck WA1003 showed a significant amount of detail was present on the wreck. It was not possible to accurately identify what these features were and so the wreck was identified as a large metal hulled vessel. The soundings from the multibeam data identified just one main upstanding feature which was tentatively identified as being the bridge. The ROV survey showed that the geophysics interpretation was incorrect and that the site was a submarine. Using this information it is possible to re-examine the sidescan sonar data and identify many of the features which are now known to be present such as the coning tower and deck gun.

Sub Plan

Site Layout

The general site layout can be seen on our clickable site plan.
 
The vessel is lying on even keel with a slight list to port on the fairly flat seabed in a NNW-SSE orientation. The bow is in the SSE.
 
The 2005 multibeam survey gives dimensions of 58m x 5m x 3m for the wreck. Dimensions taken off the sidescan data suggest a length of 66m, a breadth of 6.5m and a height off the seabed of 3.5m for the wreck itself.
 
The outer hull of the vessel has largely disappeared, but the internal pressure hull is fairly intact. The bow and stern are heavily damaged and broken up from the bow bulkhead forward and the stern bulkhead aft. The bow has collapsed and is lying partly buried in line with the vessel. The stern section has broken off and is lying at a 90 degree angle to the main hull, pointing westwards.
 
Apart from the features associated with the damaged bow and stern sections, outlying debris noted around the site consisted mainly of pressure cylinders that have fallen off the pressure hull. A large seabed scour was noted on the eastern side of the wreck.

Construction

Forward Torpedo tubeForward Torpedo tubeThe wreck shows the twin hull construction typical of U-boats: a pressure resistant inner hull and free flooding outer casing.
 
The cylindrical pressure hull is built from riveted 12mm nickel-steel plates with external steel frames. The inside of the pressure hull is separated into compartments by a number of bulkheads made from 16-21mm thick steel. The forward and aft collision bulkheads are visible where bow and stern are damaged.
 
Conning tower hatchConning tower hatchOn the outside, the pressure hull is completely surrounded by outer casing made from 3.5-4mm thick galvanised torpedo-boat steel. The outer casing protected the pressure hull. The rigid connection of outer casing and pressure hull enhanced the strength of the pressure hull. On the wreck the outer casing is only partially preserved and the pressure hull is clearly visible in the upper deck area.
 
Forward Escape hatchForward Escape hatchmade from 30mm galvanised steel is riveted onto the pressure hull. It is fully preserved with only the protective casing and armour missing. Recesses for the navigation lights and maintenance access hatches are visible either side of the tower. The main conning tower hatch is situated aft of the periscopes and was found slightly ajar.
 
Aft torpedo tubeAft torpedo tubeTwo torpedo loading hatches were observed at bow and stern, aft and forward of the torpedo rooms. At the stern of the vessel, the engine room escape hatch is wide open. The forward escape hatch is sealed.
 
At the bow of the u-boat, the two bow torpedo tubes are split at the forward collision bulkhead. The tubes have an internal diameter of ca. 58cm. The tube construction with outer reinforcement rings and bolted segments is clearly visible.

The two stern tubes are heavily damaged and lie at a 90° angle to the hull within the stern wreckage. The outer torpedo tube door is visible on one of the aft tubes.

Fittings and Machinery

WindlassWindlass Most of the fittings that were originally located on the upper deck of the U-boat are in place. The patent anchor is secured in the hawsehole in a recess on the side of the damaged bow section.
 
Using the ISS camera, it was possible to obtain some measurements: the anchor shaft is 13cm wide. The anchor fluke measures 24cm x 20cm. The electrical anchor windlass and capstan is in place just aft of the anchor. The opening for the windlass drive shaft can be seen in the collision bulkhead above the two torpedo tubes.
 
AnchorAnchor There are a number of compressed air cylinders on top of the pressure hull along the length of the upper deck. These formed part of the boat’s compressed air system which was used to blow air into the dive and ballast tanks. All the cylinders were connected to a compressor in the control room and could be centrally recharged when the U-boat was on the surface. The individual air cylinders are 46cm wide.
 
The U-boat was armed with two upper deck guns forward and aft of the conning tower. The forward gun is still attached to its mounting and is trained upward. It is well preserved with only a small amount of fishing gear snagged around the barrel.
 
Due to low visibility and strong currents, it proved difficult to obtain accurate measurements with the ISS camera. However it appears that the calibre of the gun is larger than 10cm. The gun is fitted with a horizontally sliding breech block and top-mounted recoil cylinders.
 
Forward GunForward Gun A comparison with small calibre naval guns in use during the First World War shows that it might be a German 10.5cm/45 (4.1") Ubts L/45. This gun was in service from 1907. It was used to arm cruisers, but later in the war it was also fitted on destroyers and submarines. A 10.5cm Ubts L/45 gun from U-98 is preserved in the Imperial War Museum, London.
 
Aft GunAft Gun The aft gun is also attached to its mounting but has fallen over to the port side. This gun appears to be the standard World War One U-boat gun, the 8.8 cm/30 (3.46") Ubts L/30. This gun is attached to a circular mounting rather than the collapsible mounting used on some U-boats. The 8.8cm L/30 Schnelladekanone was originally developed for river and coastal gunboats by Krupp in 1898. During the First World War it became standard U-boat armament. An 8.8cm L/30 gun from the wreck of UB-61 is on display in the Bavarian Army Museum in Ingolstadt.
 
Conning TowerConning Tower On the conning tower, the mountings for three periscopes are visible. The two main periscope mountings are situated on top of the conning tower, forward of the escape hatch. Both periscopes were operated from the conning tower. The mountings seem to be empty and the periscopes could not be seen. The mounting for the emergency periscope is situated just forward of the conning tower. The emergency periscope was operated from the control room.
 
VentilationVentilation The column for the bridge steering wheel is situated forward of the two main periscopes. The main steering controls were located in the conning tower, but additional steering wheels were situated on the bridge, in the control room and aft in the torpedo room.
 
 The U-boat’s ventilation system has collapsed onto the upper deck and is lying across the hull aft of the conning tower. At the stern the two propellers are still attached to the shafts. The port propeller is missing one of its blades. An intact blade could be measured with the scaling camera. The blade is 75cm long and 40cm wide.

 

Identification

Wreck WA 1003 is a submarine or U-boat. The vessel is between 58m and 70m long and has a beam of c. 6.5m. The exact length is difficult to determine due to damage to the bow and stern. It stands 3m proud of the seabed, but is partly buried.
 
The submarine is armed with four torpedo tubes, two bow tubes and two stern tubes. Two deck guns, consistent with guns used on German u-boats during the First World War are visible. No evidence of mine launching chutes could be found.
 
The size of the vessel, the absence of mine launching equipment and the general layout suggest that WA 1003 is the wreck of an oceangoing German attack U-boat from the First World War.
 
As a construction and general layout plan of U-63 to U-65 was available during the ROV survey, features observed on the seabed could be compared to this plan.
 
Apart from a number of details on the conning tower, all fittings and machinery were consistent with the plan. It could thus be concluded that the U-boat was of the so called ‘Ms’, or Mobilmachungs (mobilisation) type.
 
Ms boats were built by a number of different shipyards and were constantly improved. This led to a variety of subtypes, all with slight variations. Each subtype was named after the first boat built to the specification.
 
Further study showed that the wreck was consistent with the subtype U-81. This type of U-boat was built at the Germania Werft in Kiel between 1915 and 1916. There were six boats in the U-81 type: U-81 to U-86. Four of them were sunk during the war around Ireland or in the Atlantic. One boat was broken up (uboat.net).
 
Only U-86 is stated to have sunk or been sunk in the Channel after having been used by the British Navy in 1921. WA 1003 has therefore been identified as the German Ms-type u-boat U-86.
 
Using archaeological and documentary evidence it is possible to describe the U-86 in some detail.

Technical Specifications

U-86 (Construction No 256) was ordered at the Germania shipyard in Kiel on the 23rd June 1915. The keel was laid on November 5th, 1915 and the boat was launched on November 7th 1916.
 
The technical specification of the boat was:
 
Displacement (m³) surfaced
808
Displacement (m³) submerged
946
Length (m)
70.1
Beam (m)
6.3
Draught (m)
4.0
Propulsion Main (no. x hp)
2x 1200 Diesel MAN
Propulsion EL (no. x hp)
2x 600 EM
Fuel Capacity
81+38
Speed surfaced (kn)
16.8
Speed submerged (kn)
9.1
Range surfaced (nm/kn)
11200/8
Range submerged (nm/kn)
56/5
Armament
2 bowtubes, 2 sterntubes, 8 torpedoes (50cm), originally 2 x 8.8cm guns, archaeological evidence for U-86 shows that the bow gun has been replaced by a 10.5cm gun

 

It's History

U-86 was commissioned on 30 November, 1916 and served until it was surrendered at the end of the War.
 
It’s first commander was Kapitänleutnant Friedrich Crüsemann, who was in charge of the boat until June 22nd, 1917. On June 23rd Kapitänleutnant Alfred Götze took over as commander. Oberleutnant zur See Helmut Patzig was the last commander of U-86. He was appointed on January 26th, 1918 and served until the boat was surrendered at the end of the war on November 11th, 1918.
 
Between 1917 and 1918, U-86 was assigned to the 4th U-Flotilla. Altogether the boat conducted 12 patrols. It sank a total of 33 ships (125.580 tons), warships excluded.
 

In 1918

As an example for the general service of U-86, information for the year 1918 has been extracted from the German naval war diary.
 
In 1918 U-86 conducted operations in the Skagerrak (the waters between Norway and Denmark), the Irish Sea, the North Sea and the Bristol Channel. It sank the following ships:
  • the British steamer Kafue (6044grt): 1 May, 1918
  • the British steamer Medora (5135grt): 3 May
  • the British steamer Leeds City (4298grt): 7 May
  • the Norwegian steamer San Andres (1656grt): 12 May
  • the British steamer Atlantian (9399 BRT): 26 June
  • the US troop transport Covington (16,339grt):1 July
In June 1918 U-86 was involved in one of the worst war crimes committed by a U-boat commander during the First World War, the sinking of the British hospital ship Llandovery Castle and the subsequent murder of the surviving crew members in the water.
 
The Llandovery Castle, clearly marked as a hospital ship and known to the German government as such, was en route from England to Halifax, Canada, with nurses, officers and men of the Canadian Medical Corps on board when she was torpedoed by U-86 in the evening of June 27, about 116 nautical miles south-west of Fastnet.
 
According to witness statements at the later Leipzig war crime trial, the commander of U-86, Oberleutnant zur See Patzig, gave the order to torpedo the Llandovery Castle even though he knew that she was a hospital ship, the sinking of which was illegal under international law and the Hague convention.
 
Even though the Llandovery Castle sank within ten minutes, a number of boats were lowered successfully and the ship was abandoned in a calm and efficient manner. The lifeboats proceeded to rescue survivors from the water but were interrupted by Patzig, who started interrogating crew members to obtain proof of the misuse of the hospital ship as an ammunition carrier.
 
When no proof could be obtained, Patzig gave the command ‘Ready for Diving’ and ordered the crew below deck. Only himself, the two accused officers and the boatswain’s mate Meissner stayed on deck.
 
However, the U-boat did not dive, but started firing at and sinking the life boats in an attempt to kill all the witnesses in order to cover up the incident. To conceal this, Patzig extracted promises of secrecy from the crew, and faked the course of U-86 in the logbook so that nothing would connect U-86 with the sinking of the Llandovery Castle. Of the 258 persons on board only 24 survived.
 
After the war Patzig fled the country and only the first and second officer of U-86, Dithmar and Boldt could be arrested and tried for their action in the incident.
 
At the Leipzig trial, both Dithmar and Boldt were sentenced to four years of hard labour. Patzig, with whom the responsibility for the incident rested was never found and prosecuted. Dithmar and Boldt were both released from prison after a few months due to the political changes in Germany.
 
U-86 was in the first group of u-boats that were handed over to the Allies as part of the armistice treaty at the end of the war. She was taken from Brunsbüttel, Germany to Harwich, England, on November 20th, 1918. From September 1919 to March 1920, U-86 was commissioned into the Royal Navy to test her design and make comparisons with other classes and later designs.
 
After decommissioning U-86 was scuttled at sea at the end of June 1921. The evidence of the ROV survey suggests that the bow and stern of the U-boat may have been blown off to sink the vessel.

Sources

The following webpages contain material related to U-86:
 
The plans for U-63 were found on this webpage. The page also contains a wealth of information relating to naval technology of WW1.
 
The naval archive in the Bibliothek für Zeitgeschichte in der Württembergischen Landesbibliothek holds an extensive collection of photographs of U-boats from both World Wars.
 
U-boat net is probably the most extensive web archive of everything and anything related to U-boats.
 
This webpage has extensive information on the sinking of the Llandovery Castle.
 
Information on the guns on U-86 was extracted from these two webpages.

Media

Methodology Results

In summary, the project has shown that Remotely Operated Vehicles (ROV’s) are effective tools for the archaeological survey of deep wreck sites.
 
It was possible to define the extent, character, date and also the importance of wreck sites.
 
Even detailed measurements of objects on the seabed could be achieved with the scaling camera on the ROV. However; just like divers, ROV’s are affected by tidal currents, low visibility and marine growth hiding important features.
 
While divers might be the better solution for detailed archaeological surveys on shallow wrecks, they are unlikely to provide a cost-effective solution for deep shipwreck surveys.
 

Want to know more?

When looking at the methodologies for assessing, evaluating and recording wreck sites in deeper water, it was found that the general approach to the ROV survey did not differ very much from the approach taken on the shallow sites. However, a few alterations to the survey plan had to be made:
 
As the quality of the geophysical background data was fairly low, additional dives were necessary to obtain a general overview of the site and establish the type of site. The use of a digital stills camera and the Tritech ISS scaling camera allowed to take recording from level 2 to level 3 on one site.
 
Generally, the adverse underwater conditions on site necessitated a high degree of flexibility in the survey procedures.
 
One of the objectives of this round of the project was to assess the effectiveness of undertaking archaeological recording using ROV and geophysical techniques only. It became apparent that using the geophysical data only, partial level 1 recording was possible. While presence and position of the sites could be established, the available information was not sufficient to determine the type of site.
 
Applying the methodology outlined before, all deep wreck sites could be recorded to level 2. The use of a scaling camera and a digital stills camera on the ROV allowed partial level 3 recording, even in the low visibility conditions and strong currents experienced on the study sites.
 
However, it was found that the four main factors limiting survey efficiency that were identified during the shallow water ROV survey in Year One (2005) also affected the deepwater survey. These were:
  • visibility
  • tidal current
  • access, and
  • marine growth
The poor visibility experienced on all of the deep wreck sites made underwater orientation and video recording very difficult. It also limited the use of the underwater stills camera.
 
Most importantly, the duration of all recording tasks had to be changed as even simple tasks took much longer. Despite this, it proved to be possible to carry out recording, mainly because of the skill and experience of the ROV operator.
 
The strong tidal currents experienced on all sites limited diving to the slack-water periods and made it difficult to control the ROV. Again the survey efficiency depended mainly on the skill and experience of the ROV operator and on a high degree of flexibility in the survey planning.
 
The problems of access to enclosed areas on structurally coherent wrecks and dense marine growth preventing the identification and recording of features are indicative for ROV surveys in all environments. These have to be accepted as general limitations.
 
No environmental issues relating specifically to the location of the sites in deeper water could be identified. The conditions experienced were related to the time of year and the unusual general weather conditions rather than to the location of the sites in deeper water.
 
When assessing issues related to infrastructure, the choice of support vessel was found to be a critical factor. Using Sara Maatje XV, none of the problems identified during the Year One survey were encountered. The vessel was equipped for establishing three- or four point moorings and the crew was very skilled and experienced. The mooring procedure on each wreck site took an average of 30 minutes and the vessel was generally secured directly above the wreck. Umbilical handling was carried out by the crew and did not pose any additional problems.
 
>In conclusion, the project has improved the knowledge necessary for specifying and conducting rapid and efficient deepwater ROV wreck surveys in areas with conditions similar to the English Channel.

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