Table Of Content9781405175913_1_pre.qxd 5/8/08 9:46 AM Page i
Underwater Archaeology
The Nautical Archaeology Society also publishes The International Journal of Nautical Archaeology with Blackwell
Publishing, a new series of monograph reports and a members’ newsletter, Nautical Archaeology. It runs several
public participation projects.
Underwater Archaeology: The NAS Guide to Principles and Practice Second Edition Edited by Amanda Bowens
© 2009 Nautical Archaeological Society ISBN: 978-1-405-17592-0
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Second Edition
Underwater Archaeology
The NAS Guide to Principles and Practice
Editor: Amanda Bowens, BA MA
THE NAUTICAL ARCHAEOLOGY SOCIETY
FORT CUMBERLAND
FORT CUMBERLAND ROAD
PORTSMOUTH
PO4 9LD, UK
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This edition first published 2009
© 2009 by Nautical Archaeological Society
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Library of Congress Cataloging-in-Publication Data
Nautical Archaeology Society.
Underwater archaeology : the NAS guide to principles and practice / author, the Nautical Archaeology Society; editor,
Amanda Bowens. – 2nd ed.
p. cm.
Includes bibliographical references and index.
ISBN 978-1-4051-7592-0 (hardcover : alk. paper)—ISBN 978-1-4051-7591-3 (pbk. : alk. paper) 1. Underwater archaeology.
2. Shipwrecks. 3. Underwater archaeology—Handbooks, manuals, etc. I. Bowens, Amanda. II. Title.
CC77.U5N39 2009
930.1′028′04—dc22
2007048319
A catalogue record for this book is available from the British Library.
Set in 10.5/12.5 Minion
by Graphicraft Limited, Hong Kong
Printed and bound in Singapore by C.O.S. Printers Pte Ltd
1 2009
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Contents
List of Figures viii 5 Project Planning 34
List of Plates xi The Project Design 34
Foreword xiii Further Information 37
Acknowledgements xiv
6 Safety on Archaeological Sites Under
Water and on the Foreshore 38
1 The NAS Handbook – Why It Was
Risk Assessments 38
Written 1
Diving Project Plan 39
Codes of Practice 39
2 Underwater Archaeology 2
Control of Diving Operations 40
What Is Archaeology? 2
Working Under Water 40
What Is Archaeology Under Water? 5
Potential Diving Problems and Solutions 40
What Is Not Archaeology Under Water? 6
Safety During Excavation 42
Closely Related and Complementary
Inter-Tidal Site Safety 43
Approaches (Ethnography and
Further Information 44
Experimental Archaeology) 8
Further Information 10
7 International and National Laws Relating
to Archaeology Under Water 45
3 Getting Involved in Underwater and
Jurisdiction – Where Do the Laws
Foreshore Archaeology 11
Apply? 45
Further Information 13
The Regime in International Waters 46
International Salvage Law 47
4 Basic Principles – Making the Most Underwater Cultural Heritage and
of the Clues 15 Salvage Law 47
The Importance of Underwater Sites 15 Ownership of Underwater
Site Types 17 Cultural Heritage 48
The Range of Evidence on an Abandonment of Ownership 48
Archaeological Site 19 National Legislation 48
Links Between Categories of Evidence 22 International Conventions 49
Using the Evidence 22 Case Studies 50
Dating 24 Further Information 52
Environment and Site-Formation
Processes 28 8 Archaeological Recording 53
The Deterioration of Wood 30 The Need for Recording 53
Culture and Site-Formation Processes 31 Recording Systems 54
Further Information 33 Planning the Recording: What to Record 54
v
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vi CONTENTS
Recording Information On Site 54 13 Geophysical and Remote-Sensing
Recording Timbers 57 Surveys 103
Recording Contexts 58 Search Patterns, Navigation and
Recording Stratigraphy 58 Positioning 103
Recording Environmental Evidence 60 Acoustic Systems 104
Recording Samples 60 Bathymetric Survey 104
Recording Survey Results 60 Echo-Sounders 105
Recording Plans and Sections 60 Multibeam Swath Systems 105
Recording Photographic Results 60 Bottom-Classification Systems 106
Conservation Records 61 Sidescan Sonar 107
Identifying Archaeological Material 61 Sub-Bottom Profiling 108
Tags and Labelling 62 Magnetometry 111
Storing the Information 62 Integrated Surveys 112
Computing Options and Issues 63 Submersibles: ROVs and AUVs 112
Geographical Information Systems 63 Aerial Photography 113
Explaining, Documenting, and Further Information 113
Supervising the System 63
Further Information 64 14 Underwater Survey 114
Types of Survey 114
9 Historical Research 65 An Initial Sketch 116
Types of Evidence 66 Planning 117
Locating Primary Sources 66 Setting Up a Baseline/Control Points 118
The Internet 68 Installing Survey Points 119
Methods of Research 69 The Principles of Survey 120
Further Information 70 Survey Using Tape-Measures, Grids and
Drafting Film 123
10 Photography 71 Vertical Control (Height/Depth) 124
Photographic Theory 72 Drawing/Planning Frames 125
Digital Photography 73 Grid-Frames 126
Surface Photography 74 Processing Measurements and Drawing
Photographing Finds 74 up the Site-Plan 127
Underwater Photography 75 Three-Dimensional Computer-Based
Underwater Photographic Techniques 76 Survey 127
Digital Darkroom 77 Acoustic Positioning Systems 132
Mosaics – Photo or Video 78 Positioning the Site in the Real World 133
Video Cameras 79 Further Information 134
Video Technique 80
Video Editing 81 15 Destructive Investigative Techniques 135
Further Information 82 Probing 135
Sampling 136
11 Position-Fixing 83 Excavation 141
Geographical Coordinates 84 Further Information 147
Accuracy 86
Methods of Position-Fixing 87 16 Archaeological Conservation and
Equipment 94 First-Aid for Finds 148
Further Information 95 Underwater Burial Environments 149
Materials Degradation and Post-
12 Underwater Search Methods 96 Excavation Deterioration 150
Positioning 96 Principal Risks to Finds During and
Coverage 96 After Recovery 152
Safety 96 Principles and Procedures for First-Aid
Diver Search Methods 97 for Underwater Finds 152
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CONTENTS vii
Lifting, Handling and Transportation 154 20 Presenting, Publicizing and Publishing
Approaches to Packing and Storage 156 Archaeological Work 189
Sampling and Analysis 157 The Importance of Publicizing (Where
Initial Cleaning 157 and When) 189
Holding and Pre-Conservation Identifying and Satisfying an Audience 190
Treatment Solutions 157 Methods of Presentation 191
Record-Keeping 158 Writing Reports and Publications 194
X-Radiography and Facilities 159 A Significant Achievement and
Health and Safety 159 Contribution 196
Insurance 159 Further Information 197
Checklists 159
Further Information 162 Appendix 1: Anchor Recording 198
Stone Anchors 198
17 Site Monitoring and Protection 163 Stock Anchors 199
Monitoring 163 Further Information 200
Protection 167
Further Information 169 Appendix 2: Guns 201
The Importance of Sea-Bed Recording 201
18 Archaeological Illustration 170 Identification of Material 202
Basic Drawing Equipment 170 Classification by Methods of Loading 204
Drawing Archaeological Material 171 Classification by Shape 204
Recording ‘By Eye’ 175 Inscriptions and Decoration 206
Recording Decoration and Projectiles, Charges and Tampions 208
Surface Detail 176 Recording and Illustrating Guns 209
Recording Constructional and Further Information 212
Other Detail 177
Post-Fieldwork Photography and Appendix 3: NAS Training Programme 213
Laser Scanning 178 An Introduction to Foreshore and
Presenting a Range of Complex Underwater Archaeology 213
Information 178 NAS Part I: Certificate in Foreshore and
Further Information 180 Underwater Archaeology 214
NAS Part II: Intermediate Certificate in
19 Post-Fieldwork Analysis and Archiving 181 Foreshore and Underwater Archaeology 214
Handling Material and Keeping NAS Part III: Advanced Certificate in
Records 182 Foreshore and Underwater Archaeology 214
Post-Fieldwork Treatment of NAS Part IV: Diploma in Foreshore and
Survey Work 182 Underwater Archaeology 215
Specialist Analysis 185 Further Information 215
Interpretation and Gathering Supporting
Evidence From Other Sources 186 Glossary 216
Producing an Archaeological Archive 186 References and Further Reading 219
Further Information 188 Index 223
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List of Figures
2.1 The Dover bronze-age boat 3 10.1 A diver sketching a late ninetenth-century
2.2 The fifteenth-century Newport ship 4 shipwreck in Dor, Israel 72
2.3 Experimental archaeology: building a 10.2 A simple set-up for photographing finds
replica log boat 9 using a vertical stand 74
2.4 Trials of the Loch Glashan replica 10.3 A vertically photographed wooden weaving
log boat 9 heddle from the Armada wreck La
3.1 Post-fieldwork activity 12 Trinidad Valencera (1588) 75
4.1 Archaeological sites as part of a 10.4 Obliquely photographed wooden bellows
settlement pattern 16 from the Armada wreck La Trinidad
4.2 Survival of clues on underwater sites Valencera (1588) 75
relative to dry sites 17 10.5 Important considerations for successful
4.3 An RNLI wreck chart for 1876–7 18 underwater photography 76
4.4 Site types: aerial photograph of a stone- 10.6 A 5 metre square photomosaic of ship
built fish-trap at Airds Bay, Scotland 19 remains on the Duart Point wreck 78
4.5 Tree-rings viewed through a microscope 24 10.7 A photographic tower positioned on
4.6 Tree-ring sequence built up from trees a rigid site grid 79
in the same area 25 10.8 Photomosaics: formula to calculate
4.7 Typology: how it works 27 lens focal length and camera
4.8 Stratigraphy from above: the height necessary to give the
sequence of events 27 required coverage 79
4.9 Stratigraphy: what it can reveal 28 10.9 Underwater use of a video camera 80
4.10 The importance of context and 11.1 The earth, showing latitude, longitude
stratigraphy 28 and equator 84
4.11 Site-formation processes 29 11.2 The basis of the Universal Transverse
4.12 Re-used ship’s timbers in an open barn Mercator (UTM) projection 84
on the Turks and Caicos Islands 32 11.3 A scatter of shots showing precision
8.1 In situ recording: a diver’s recording form and accuracy 86
completed during excavation of the 11.4 Taking horizontal sextant angles 87
Mary Rose in 1982 56 11.5 How to use sextant angles (scribed
8.2 Planning contexts 59 on drafting film) 88
8.3 Harris matrix 59 11.6 Sextant angles: plotted geometrically
8.4 Section through a gully on the wreck of from baselines between charted
El Gran Grifon (1588) 60 features 89
8.5 An archaeological database 62 11.7 A triangle of error, or ‘cocked hat’ 90
9.1 An eighteenth-century gravestone near the 11.8 The use of coastal features as transit
River Tay in Perthshire showing a salmon marks to establish the position of a site 90
fisherman’s square-sterned coble 67 11.9 Accuracy of transits 91
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LIST OF FIGURES ix
11.10 Temporary transits formed by setting up 15.1 Excavation strategies: trench and test pits 136
paired ranging rods along a shore baseline 91 15.2 Probing to record sediment depths and
11.11 Surveying a submerged site in shallow water obstructions 136
using a shore-based EDM 92 15.3 Use of air or water probes 136
11.12 Differential GPS system with satellites, 15.4 Optimum place for tree-ring sampling 138
shore-based reference stations and 15.5 Taking a spot sample 139
in-boat mobile receiver 94 15.6 Column or monolith sampling from a
12.1 Towed diver search 97 section 140
12.2 Swimline (freeline) search 98 15.7 Excavating a wooden weaving heddle
12.3 The offset method in use (with on the Armada wreck La Trinidad
metal detector) 99 Valencera (1588) 142
12.4 Jackstay (corridor) search 100 15.8 Excavation tools: the trowel and the
12.5 Circular search 101 paint brush 142
13.1 500 kHz sidescan sonar image of a 15.9 A conservator removing the surviving
v-shaped fish-trap from the River section of a gunpowder barrel, excavated
Barrow, County Wexford, Ireland 107 from the Spanish Armada wreck La
13.2 Sidescan sonar image of the Trinidad Valencera (1588) 143
SS Storaa (1943) 108 15.10 Excavation using airlift 144
13.3 Chirp and Boomer image from 15.11 Water-dredge operation 146
Strangford Lough, Northern Ireland 109 16.1 Teredo navalis (shipworm) 150
13.4 A two-dimensional profile and interpolated 16.2 A concretion recovered from the Duart
timeslice of the Grace Dieu (1439) wreck, Point wreck (1653) site, Mull, Scotland 152
River Hamble, Hampshire, UK 110 16.3 An X-ray of the concretion shown in
13.5 Geophysics equipment: 1) magnetometer, figure 16.2 152
2) sidescan sonar, 3) sub-bottom 16.4 The Duart Point sword hilt shown in
profiler, 4) ROV 112 figures 16.2 and 16.3 after conservation 152
14.1 Excavation plan of part of the Spanish 16.5 Excavating a small fragile object – a leather
Armada wreck La Trinidad water-bottle – from the Armada wreck
Valencera (1588) 115 La Trinidad Valencera (1588) 155
14.2 Representing the sea-bed using symbols 116 16.6 Raising a large organic object – a spoked
14.3 Radial method of survey 117 wooden wheel – from the Armada wreck
14.4 Recording the profile of a wreck using La Trinidad Valencera (1588) 155
vertical offsets from a horizontal datum 120 16.7 The leather water-bottle shown in
14.5 Offset method, including plotting results 121 figure 16.5 is brought to the surface
14.6 Ties/trilateration: survey and drawing and handed to the waiting conservator 155
up results 122 16.8 A pocket sundial with integrated
14.7 The principle of levelling to establish compass found on the wreck of
relative heights/depths 124 the Kennemerland (1664) 161
14.8 Depth relative to a temporary benchmark 124 17.1 A covering of sandbags placed over
14.9 A simple clinometer 125 a fragile area on the Duart Point
14.10 A double-strung planning frame 125 (1653) wreck, Mull, Scotland 168
14.11 A diver taking DSM measurements 128 18.1 Archaeological illustration in practice 171
14.12 Braced quadrilateral (3-D survey) 129 18.2 Recording shape: tracing round an
14.13 Joining quads (3-D survey) 129 object with a set-square and pencil 173
14.14 Measuring between quads (3-D survey) 129 18.3 Recording shape by establishing a vertical
14.15 Good control-point network shapes datum and taking offset measurements 174
(3-D survey) 130 18.4 A radius template in use 174
14.16 Secondary points (3-D survey) 130 18.5 A radius chart in use 174
14.17 Poor control-point network shapes 18.6 Correct orientation of a pottery sherd
(3-D survey) 131 when using a radius chart 175
14.18 Positioning detail points on features using 18.7 A simple pottery drawing 175
control points (3-D survey) 132 18.8 Thickness-gauge callipers in use 176
14.19 Surveying a submerged site in shallow 18.9 Archaeological illustration of a jug
water using a shore-based ‘total station’ 133 complete with spout 176
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x LIST OF FIGURES
18.10 Profile gauge in use 176 A2.2 Wrought-iron breech-loading tube gun:
18.11 Depiction of complex decoration terminology – a corresponding recording
(‘rolled out’) 177 form is available on the NAS website 203
18.12 The drawing of a complex object – swivel A2.3 Breech-loading swivel-gun: terminology
gun from La Trinidad Valencera (1588), – a corresponding recording form is
with views and details selected to convey available on the NAS website 204
the maximum amount of information 177 A2.4 A small swivel-gun recovered from
18.13 Illustration of two pairs of brass dividers a Spanish Armada wreck off
from the Dartmouth (1690) 178 Streedagh Strand, Ireland 205
18.14 Drawing of a more complex pot 178 A2.5 Plan and side view of a decorated cast-
18.15 Drawing of a boatbuilder’s tar brush bronze gun from the Spanish Armada
from western Scotland 179 wreck La Trinidad Valencera (1588) 206
18.16 A render of the 3-D laser-scan data of the A2.6 A Tudor rose heraldic emblem from
figurehead from HMS Colossus (1798) 179 one of the bronze guns from the
18.17 An orthographic view of the shaded 3-D Mary Rose (1545) 207
laser-scan data of the Mary Rose A2.7 The weight number on the breeching ring
(1545) hull 180 reinforce on the Stirling Castle’s (1703)
19.1 A plan chest for the storage of plans demi-cannon, as shown in figure A2.13 207
and drawings 182 A2.8 Founder’s mark (Thomas Western),
19.2 An example of a site-location map 183 touch-hole and details of markings
19.3 Interpreted and ‘naturalistic’ representations on the first reinforce on the Stirling
of the same section prepared for Castle’s (1703) demi-cannon, as shown
publication 184 in figure A2.13 207
19.4 Representing topography with hachures A2.9 Detail of the broad arrow on the Stirling
and contours 185 Castle’s (1703) demi-cannon, as seen in
19.5 One of the Mary Rose Trust organic stores 187 figure A2.13 207
19.6 The Mary Rose card file system 188 A2.10 Plain iron guns from the Armada wreck
20.1 A public talk during a NAS project El Gran Grifon (1588) 208
at Stourhead, Wiltshire, UK 190 A2.11 A drawing properly set out for publication
20.2 A team member being interviewed of a piece of ordnance – a cannon ferrier
for television during work on the from a Spanish Armada Wreck off
Mary Rose (1545) site 193 Streedagh Strand, Ireland 210
A1.1 Anchor terminology 200 A2.12 Rubbing taken from the top of the barrel
A2.1 Cast ordnance: terminology – a of the swivel-gun shown in figure A2.4 211
corresponding recording form is A2.13 A demi-cannon from the wreck of the
available on the NAS website 203 Stirling Castle (1703) 211
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List of Plates
Plates fall between pages 114 and 115 13.2 Surface rendered multibeam sonar image
of rock gullies off Moor Sand, UK, containing
2.1 Charles Deane diving on HMS Royal bronze-age and seventeen-century material
George (1782) 13.3 Multibeam sonar image of the
2.2 Ethnographic recording of a three-log SS Storaa (1943)
kat in Edava, Kerala, India 13.4 Multibeam image of a prehistoric land
3.1 NAS Training project near Bristol, UK surface at the base of the 8 m (26 ft) high
3.2 More archaeology on the foreshore in underwater Bouldner Cliff in the Solent,
the UK with NAS Training UK. The wreck of the 44 m (143 ft) long
4.1 A diver examining a chest of longbows dredger Margaret Smith (1978) is
on the Mary Rose (1545) included for scale
4.2 Site types: reconstruction of a crannog 13.5 High quality, diver-recorded site-plan
on Loch Tay, Scotland of the Hazardous (1706) wreck-site
4.3 The Swedish man-of-war Vasa (1628) 13.6 Multibeam sonar image of the Hazardous
6.1 Archaeological team on hookah (1706) wreck-site for comparison
preparing to dive with plate 13.5
6.2 A commercial archaeological diving unit 13.7 Multibeam image from a single pass in
working to UK Health and Safety Executive 2002 showing the sea-bed around the
protocols for surface-supplied diving wreck of the Stirling Castle (1703)
8.1 Recording timbers: 1:1 tracing of timber 13.8 Multibeam image from a single pass in
surfaces on polythene 2005 showing the sea-bed around the
8.2 Stratigraphy: an underwater excavation wreck of the Stirling Castle 3 years
face showing several stratagraphic layers after the pass shown in plate 13.7
8.3 Recording in situ: a slipware bowl during 13.9 Multibeam image of a nineteenth-century
excavation on the Duart Point wreck wooden sailing ship on the Goodwin Sands
(1653), Mull, Scotland 13.10 Ground discrimination data collected
8.4 On-site finds processing from a single-beam echo-sounder showing
10.1 Free-standing photographic tower in bathymetry, hardness and roughness of
use within a survey grid to record a the wreck of the 178 m (580 ft) long
photomosaic Markgraff (1919) in Scapa Flow
11.1 A ‘total station’ ready for use 13.11 Three-dimensional plot of magnetic
12.1 A dry run practice of a swimline data acquired from the La Surveillante
(freeline) search (1797) wreck-site in Bantry Bay
13.1 High-definition multibeam sonar point 13.12 Photograph showing a Geometrics G-881
cloud image of the 203 m (660 ft) caesium magnetometer, an EdgeTech 272-TD
long wreck of HMS Royal Oak (1939) side-scan, a GeoAcoustics side-scan and
in Scapa Flow, Orkney an Imagenex 885 side-scan sonar
