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The Late Bronze Age Shipwreck off the islet of Modi (Poros).
Author Christos Agouridis

1) Forward

The islet of Modi is situated southeast of the island of Poros (ancient Kalavreia) at an important position for navigation. Ships sailing from the Saronic to the Argolic Gulf or vice versa would pass close to its rocky slopes. Its impressive shape, like a seated lion (Liondari is a name used by local fishermen), makes Modi an important land mark for mariners traveling one of the most frequented sea routes in the Aegean.

Excavations on Modi carried out during the years 2000 and 2001 by Dr. Eleni Konsolaki-Giannopoulou, with the encouragement and help of Mr. Adonis Kyrou, who made the discovery, brought to light an impressive settlement of the LBA III period.  Dr. Konsolaki’s research on Modi, together with information obtained from fishermen and divers, ceramics found in fishing nets and handed over to the Museum of Poros, the island’s important geographical position and, finally, Kyrou’s constant encouragement and help, were the reasons that led the Hellenic Institute of Marine Archaeology (HIMA) and Christos Agouridis, maritime archaeologist and secretary general of HIMA, to plan an underwater survey around Modi islet in order to investigate the area more thoroughly. Furthermore, the accumulated knowledge of the history and archaeology of the Argosaronic region after many years of HIMA’s fruitful scientific activity (EBA wreck site at Dokos and LBA shipwreck at Point Iria) was also very important.

The Late Bronze Age shipwreck was first located in 2003 off the north rocky slopes of Modi. Research campaigns in 2005-2007 recorded and raised all visible ceramics from the ship’s cargo. Preliminary reports were published in the Journal ENALIA and were presented at various symposia. Due to the potential of the Modi shipwreck to add to our understanding of a critical period of Aegean prehistory, HIMA and the director of the project decided to conduct a full scale underwater excavation during the fall of 2009 and 2010. 

The following seasons (2011 and 2012) focused on the conservation and study of the material raised from the seabed during previous expeditions. Excavation of the site will continue in the fall of 2013.

2) Preparation and planning

The project originally began in 2008 on many different levels. Methods of survey and documentation were carefully planned, a database was specially designed as a useful tool for cataloging and processing all data from the excavation, and all necessary steps concerning recovery procedures of the finds, u/w and on land, were prepared according to specific scientific protocols. Furthermore, a diving program was formulated in order to work safely and be more productive underwater, and a geo-archaeological survey was planned in cooperation with the Laboratory of physical oceanography of the University of Patras, in order to investigate the area around the site more thoroughly and try to reconstruct the ancient environment. Communication with the Goulandris Museum of Natural History was established for studying mollusks and shells from the site. Finally, fund raising occupied much time and effort (see below).

'Agios Nikolaos' boat

 

Mr. Evangelos Pissias, an Institute supporter, generously offered the “AGIOS NIKOLAOS,” a 19 m long wooden fishing boat, to be the project’s support vessel. Before the boat could be used, it needed extensive repairs and adaptations to safely support an underwater archaeological expedition. The boat’s preparation was carried out a few months earlier. Volunteer members of HIMA completed all the necessary  work under the guidance of the project’s technical director Markos Garras. Two additional rigid inflatable boats (zodiacs) supported the expedition. The boat sailed from its home port at Salamis and arrived at Poros carrying it’s rigging and anchorage (for anchoring both at Modi over the site and at the harbour close to our camp), as well as the mechanical and technical equipment needed for the underwater excavation and supplies necessary for life on board.

 

During the 13 weeks of field work, 40 people participated on a volunteer basis (archaeologists, architects, surveyors, conservators, photographers and cameramen, a physicist specializing in hydro-acoustics, a team of geologists-oceanographers, marine biologists and divers/technicians). Various factors guided personnel distribution. An average of 15 people worked in the field daily. The team operated usually during difficult weather (northern winds over 5 B and rain). All the members of the team worked hard, with enthusiasm, team spirit and humor. Without them nothing would have been accomplished (see participants at bottom of the page).

During 2009 and 2010 field campaigns 670 dives were made and 534 hours were spent underwater. Working time at the bottom was 40 minutes using nitrox 36 and 10 minutes of decompression with pure oxygen.

During the excavation a film crew operated together with the team in order to create a documentary. Shootings were conducted underwater, aboard the ship as well as on the LBA settlement at Modi. In addition, a helicopter flying above the area of the site made aerial filming possible.

3) Surveying and Documentation Methods

During the 2005 and 2006 seasons an overview of the whole site of the wreck was created using both conventional multi-tape trilateration methods combined with depth measurements, as well as SHARPS1 (Sonic High Accuracy Ranging and Positioning System). Furthermore, a photomosaic2 of the site was created in order to have a general overview of the site. Additionally, a 3D map of the seabed was made with the use of Cobra Tac (a sonar device offered by the greek army). A parallelogram perimeter was created around the main finds with the use of iron rods and rope. All surface finds were documented with reference to the fixed points of that original perimeter. These two methods of recording were overlaid to produce a complete site plan of the wreck, as well as to compare the results for research purposes. The positioning of the wreck was also geo-referenced through the fixed points of the perimeter using a global GIS referencing system.

During the 2009-2010 field seasons wreck documentation focused on future areas of excavation. In order for all the areas of interest to be included in an array of fixed points, the original perimeter was extended to the north, east and west, with the addition of close to parallel lines in those three directions. The original perimeter was now included in a reference grid composed of fixed points placed on the seabed and tagged with letters A1, A2, A3, B1, B2,….Δ1, Δ2, Δ3 using A, B, Γ, Δ, for the horizontal lines and 1,2,3 for the vertical lines. The whole frame of fixed points was measured using conventional multi-tape trilateration and was used as a reference for documenting key finds during the excavation. Research was focused within the perimeter formed by the fixed points (A1, A2, etc.). Both conventional and photogrammetric recording methods were used to produce sections of the excavated area.

 Three dimensional plan of southwestern sectors excavated during 2010 season after processing the photogrammetric data (view from northwest)

Multi-tape trilateration and photogrammetry, with the support of software such as Site Recorder and Eos Systems PhotoModeler as well as conventional architectural scaled drawing documented the transformations of the site during the excavation.

Multi-tape trilateration mapping of the finds was done through the plotting of “Detail points” of the finds in an Autocad3D environment. Site Recorder SE software processed the underwater measurements taken from the reference frame of fixed points and the results were exported into Autocad 3D environment. Secondary fixed points placed close to the finds being excavated allowed for more accurate measurements. Those secondary fixed points were tagged with the letters Σ1, Σ2, Σ3, Σ4, Σ5 and were also referenced via measurements to the grid of primary fixed points. Two-dimensional plans, sections and elevations of the excavation trench were created in this way to record the stages of the archaeological research.

 

The photogrammetric surveying of the wreck was done with a CANON A620 camera using a 35mm lens, in an IKELITE housing. Eos Systems PhotoModeler software oriented the photographs and plotted the points in a three dimensional environment.

For PhotoModeler, specially made plates were fitted to the fixed points of the grid or placed within the area of the trench. PhotoModeler automatic target program produced the targets used for the point scanner process. The targets were printed on waterproof adhesive paper, and attached to 10 x 10 cm and 130 x 10 cm Plexiglas plates accordingly. The 10 x 10 cm plates were fixed to a base, which could easily be screwed on to the top of the poles of the primary and secondary fixed points of the grid. The 130 x 10 cm plates were negatively buoyant, and could be placed conveniently within the area being photographed, in order for Photomodeler to produce a local reference frame of fixed points for the generation of the 3D point cloud. The combination of trilateration measurements and photogrammetric surveying performed on a daily basis produced as much data as possible for plans during the excavation and for more detailed results after further processing.

4) The excavation.

During the 2009 and 2010 work was conducted in eight sectors. Half of them were excavated to bedrock. Excavation presented great difficulties. The morphology of the seabed is extremely rugged. The site is covered with rocks rolled down from higher levels and from the land. Finds were heavily concreted to the seabed with hard marine concretions. Much time and effort was spent detaching the finds. The sectors selected for further research, before being excavated were cleared of large rocks and stones which were carried outside the perimeter to a specific deposit area. We estimate that 12 m³ of rocks have been removed so far from the site. Excavation started from the two southern sectors Α1Β1Β2Α2 and Α2Β2Β3Α3 and continued to the North. Excavation reached a depth of 1.20 m. Stratigraphy was as follows: a) A surface layer of thick sand and rocks; b) a layer of conglomerates, sand, rocks, pottery sherds and shells concreted with biogenic marine concretions; c) the same layer containing mud instead of sand; d) limestone bed rock.

All u/w works were monitored for safety reasons and recorded by an ROV. All works on land, underwater and on board the research vessel were filmed with Full High Definition cameras for a documentary.

5) The finds

From the area excavated so far, a very interesting pottery assemblage of transport vessels belonging to the ship’s cargo was recorded and raised to the surface. The assemblage comprises:

Undecorated jar M 7i) Eleven (11) large undecorated jars (M7, M8, M73, M69, M79, M80, M23, M12, M75) two almost intact (M7 and M29) and the rest in fragmentary condition. Together with other jar fragments collected from the research area, raise the total number of two-handle jars to at least fifteen (15) items. They belong to the same type with a spherical-ovoid body, flat base, high cylindrical neck and two horizontal handles on the body. The type compares favorably to the cargo of the Point Iria wreck and other centers of the Peloponnese, such as Prosymna, the Palace of Nestor in Pylos and recently Salamis, dated to the LH III B-C period.

ii) A large jar (M58) unique so far in the cargo (description of the situation on the seabed). It differs from the type mentioned above as it has a relief-decorated band with multiple triangles on the junction of the neck to the body. Lower, on the shoulder, it has a rope band with engraved parallel lines. Furthermore, it has two deep engravings under the handles, most probably potter’s marks.

iii) Two pithoi recognized in the cargo with similar characteristics but without the handles. Pithos M14 was raised intact during 2007 campaign. After its desalination process was completed, first mechanical cleaning of its surface showed a relief band with fishbone engravings on the junction of the neck with the body. Parallel evidence documented in context in Mycenae belong to a Late Heladic III B horizon. Pithoi as transport vessels over long distances for liquid or other commodities, are well known from the three other wrecks of the 14th and 13th centuries (Cape Gelidonya, Uluburun and Point Iria) and they are of Cypriot origin. However, the intact pithos from Modi has more parallels with vessels found at Pylos and Mycenae rather than the Cypriot examples. It is smaller and it has one relief ring at the junction of the neck and the body, in contrast to the Cypriot pithoi from Point Iria, bearing three parallel relief rings in the same position. After close examination, the impression given by the shape and fabric point to a common origin of both types of jars, with and without handles on their body.

Hydria M13 from Modi shipwreck's cargo (photo P. Vezyrtzis)iv) Thirteen (13) hydrias were found in fragmentary condition. Three of them (M13, M18 and M57) were inside the bellies of the jars M27 and M58 (concentration showed on pics 1 and 2). It is possible that this group of overlapping vessels, may reflect how the cargo was originally stowed. A group of at least seven hydrias was found in sector Γ1Γ0Δ0Δ1. One more hydria (M86) with the same characteristics was detached in many fragments from the mouth of the jar M7 and from the rocky seabed. They belong to the same type and have an ovoid body, ring base, high neck, two horizontal cylindrical handles on the body and one vertical, elliptical handle from rim to shoulder. Their vertical handles were pierced before firing with one thin vertical hole. They survive in pieces that can make up whole artifacts after conservation. After their surface was cleaned of marine concretions, decoration with two parallel lines on their shoulders appeared. Their decoration and general shape, find close parallels in Mycenae assigned to a LH III B and C horizon.

v) Two small jugs (M68 and M86) were found almost intact, in a pocket of the bedrock, under the M13, M18 and M27 assemblage. The jugs have parallels to vessels found at Asine and Mycenae dated to LH III B and C period.

vi) Many pottery sherds were collected from the sediment coming from the rocky slope of Modi which covers the site with conglomerates, concretions and rocks. Between them we can distinguish half of a hemispheric kyathos, sherds from decorated skyfoi, an alabastron (an alabastron or an alabaster ? ), cooking pots and a Ψ type figurine.

Apart from investigating the five sectors mentioned above, the whole site was cleaned and surveyed. All exposed and visible finds were recorded. The jars, pithoi and hydrias mentioned above, together with other fragments such as bases, rims and handles located and recorded to date, raise the number of transport vessels from the ship’s cargo to at least 30 items. Further research will add more information about the size of the ship and its cargo.

6) First Aid and Conservation of the finds.

Five archaeological conservators worked on the project. Among their responsibilities were the immediate storage of the finds in plastic tanks of sea water and the care of keeping them fully impregnated all the time. The upper deck of the boat was arranged as a work area for the conservators. Where needed, the surfaces of the finds were cleaned mechanically by removing the adhering vital and phytogenic marine life, and in other cases, the concretions from encrusted shreds. All treatments were recorded on a conservation report created for the needs of the excavation. Moreover, conservators helped archaeologists to document the finds by registering and photographing them. Diving conservators had as their main task the detachment and release of pottery finds, strongly concreted to the surrounded rocks, so that they could be raised to the surface safely. A variety of tools were used for releasing these finds, such as: sharply ended chisels and sledgehammers. In one case a soft foam cushion was used successfully as a supporting medium for absorbing vibrations during mechanical detachment.

7) Marine biology.

Conservators were also responsible for collecting shells (both fossilized and alive) that were either salvaged by the divers during excavation or picked out on the surface during the sorting of the air-lift’s basket. Shells were initially stored in sea water, gradually desalinated and finally stored in a solution of 70% ethanol in tap water. Our collaborators, Dr. Vardala from the Goulandris Natural History Museum at Athens and Prof. Theodorou from the University of Athens, have already provided us with a detailed report with the actual names of the shells found attached to the shipwreck’s finds. Further study may show whether the cargo created an environment, which favored the development of certain marine species.

8) Geo-archaeology.

A Geo-archaeological survey was planned and carried out in cooperation with the Laboratory of Marine Geology and Physical Oceanography of the University of Patras, under the coordination of Prof. George Papatheodorou. The Modi marine remote sensing survey is an ongoing research project designed:

to define the evolution of the coastline configuration around Modi islet over the last 18,000 years based on the mapping of palaeo-shoreline features,

- to define the sub-bottom stratigraphy of the recent sediment sequence,

- to detect targets (surface and subsurface) of potential archaeological interest, and

- to produce a detailed bathymetry of the northwestern coastal zone of Modi islet.

Furthermore, sediment samples will be collected to define in more detail the rate of sedimentation in the study area. Data are under analyses and results are expected to guide the continuation of the survey in the future.

9) Conclusions.

The cargo found at Modi is from a Late Bronze Age shipwreck, possibly associated with the life of the Mycenaean settlement on Modi during its flourishing period. It is the second wreck of this period located so far in Greek waters (the first is from the Point Iria, presently on display at the Museum of Spetses). The finds from the Modi wreck present a unique opportunity to study a late Mycenaean pottery assemblage with typological and chronological homogeneity, pointing possibly to a common origin. The cargo of the wreck can be placed at the LH III horizon (13th -12th c. BC). Further research and study of the finds, especially those with painted decoration, which are currently in the process of desalination and conservation will give us a more precise date. Additionally, provenance studies of the cargo planned for the future through petrographic analyses are expected to illuminate the problems of sea routes and trade networks during the critical transitional period of Aegean prehistory which follows the decline and abandonment of the Mycenaean palaces and the collapse of their centralized economy. Furthermore, it will help to interpret the role that the settlement on Modi would have held as an important maritime stop over and distributor of goods in the Argosaronic Gulf and the Aegean in general.

Modi research team 2009-2010

- Agourides, Christos – archaeologist, director
- Antonopoulos, Phaidon – diving supervisor
- Agapakis, Alexander – diver, captain
- Argiris, Xanthe - archaeologist
- Zissi, Aggeliki - conservator
- Dionisopoulos, Achilleas - archaeologist
- Garras, Markos – physicists, technical director
- Kavalaris, Kyriakos - diver, captain
- Kouvelas, Athanasios – diver
- Kouvelas, Elias - diver
- Koutsouflakis, Georgios – archaeologist
- Michalis, Myrto – archaeologist, assist. director
- Michaelides, Georgios – topographer
- Marsinopoulou, Despena – conservator
- Maglis, Agellos – civil engineer
- Mentogiannis, Vassilis – photographer
- Mari, Alexandra - archaeologist
- Nakas, Ioannis – archaeologist
- Oikonomopoulos, Gregorios – diver
- Papadopoulou, Chrisanthi – archaeologist
- Papageorgiou, Kyriakos – topographer
- Sapountzis, John – archaeologist
- Sklavounakis, Panagis - archaeologist
- Sotiriou, Alexander – diver
- Solterman, Marion - diver
- Spondylis, Elias – archaeologist
- Tsabourakis, Petros – diver
- Tzanoudakis, Nikos – diver
- Tsobanidis, Agellos – conservator
- Tzortzatou, Dona – archaeologist
- Vassiliades, Konstantinos - conservator
- Vlahaki, Photini – architect
- Volikou, Maria - archaeologist

Geologists - University of Patras

- Papatheodorou, Georgios: Asist.Professor
- Geraga, Maria
- Christodoulou, Dimitris
- Fakiris, Elias
- Iatrou, Margarita
- Tsabouraki, Konstantina

Sponsors and supporters 2009-2010

INSTAP
Stavros Niarchos Foundation
Motoroil Hellas
Ellactor LTD
Prefecture of Pireus
Municipality of Poros
Ministry of Health and Social Security
Mrs. E. Darsinou
Mr. E. Pissias

Selected bibliography - Papers and Research Reports on Modi shipwreck.

2002, “Underwater survey in the Argolic Gulf, 2000”, ΕΝΑΛΙΑ, vol. VI, 32-39.
2004, “Underwater Archaeological Research in the Argolic Gulf, 2003”, ΕΝΑΛΙΑ, vol. VIII, 28-44.
2007, “Underwater Archaeological Research in the Argolic Gulf, 2005”, ΕΝΑΛΙΑ, vol. Χ, 12-30.
2009, “The Late Bronze Age shipwreck at Modi. Preliminary report”, in ΤROPIS X, 10th International Symposium on Ship Construction in Antiquity, Hydra 2008 (in press).
2012, “Underwater Archaeological Research in the Argolic Gulf, 2006-2007”, ΕΝΑΛΙΑ, volume ΧΙ, 70-85.
2012, “The Late Bronze Age shipwreck at the islet of Modi (Poros)”, in SKYLLIS, Zeitschrift für Underwasserarchäologie 11, 2011, Heft 2, p. 25-34, DEGUWA 2012.


1 SHARPS (Sonic High Accuracy Ranging and Positioning System). A high accuracy acoustic triangulation system for mapping and measuring the sea bed and/or objects laying on the sea bed. The system has a range of up to 1000 m and an accuracy of +- 3 mm at a distance of 100 m.

2 A technique used widely on land for joining multiple images to form one final image. We have developed a method, using open source software, which has the possibility of joining thousands of images to create a full image of an underwater site for reference purposes.

A pithos (M14) was raised inctact from Modi shipwreck's cargo. Here after raising (photo P. Vezyrtzis) A pithos (M14) was raised intact from Modi shipwreck's cargo (drawing J. Nakas) A pithos (M14), detail of the relief and incised decoration on the junction of the neck to the body (photo P. Vezyrtzis) A two handled jar (M29) was raised intact from Modi shipwreck's cargo (drawing J. Nakas).jpg A two handled jar (M29) was raised intact from Modi shipwreck's cargo (photo P. Vezyrtzis) General plan of the excavated area during 2010 season HIMA's research vessel AGIOS NIKOLAOS over the research area HIMA's research vessel AGIOS NIKOLAOS Hydria M77 from Modi shipwreck's cargo in situ. Painted decoration of parallel lines on the shoulder appeared during excavation (photo V. Mentogiannis) Photogrammetric surveying ROV that helped to monitor underwater works (photo V. Mentogiannis) Section elevation of sectors A1A2B2B1 and A2A3B3B2 Side scan sonar survey was conducted in cooperation with the University of Patras The upper part of a jar (M58) with relief decoration (photos P. Vezyrtzis) The upper part of a jar (M58) with relief decoration on the shoulder and deep engravings under the handles (photos P. Vezyrtzis) Three dimensional  plan of the excavation area during 2010 season after processing the photogrammetric data Three dimensional plan of southwestern sectors excavated during 2010 season after processing the photogrammetric data (viewed from northwest) Works underwater (photo V. Mentogiannis) Works underwater were filmed with Full High Definition cameras and monitored by a ROV (photo V. Mentogiannis)

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