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Engineering in the Ancient World
Reconstructing the Trireme
Stephen Ressler, P.E., Ph.D.
Professor Emeritus
U.S. Military Academy at West Point
The Trireme
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A oared warship used throughout the eastern Mediterranean from
700 BC onward
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Rowed by 170 men on three levels
Employed primarily as a human-powered torpedo
Why is it worth knowing about?
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Instrumental in:
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Persian suppression of the Ionian revolt
Greek victory in the Persian Wars
Establishment of the Athenian empire
Conduct of the Peloponnesian War
Athens’ post-war revival
An extraordinarily
sophisticated piece of
engineering
}  An intriguing
mystery!
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The principal
means of
asserting political
power in the
eastern
Mediterranean
The Battle of Salamis (September 480 B.C.)
A perfectly optimized balance of speed,
maneuverability, and strength
Classical Athens
437-432 BC
447-432 BC
Historical Development
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3rd Millennium BC:
First evidence of
primitive multi-oared
warships
Clay models from Minoan Crete
(3000-2700 BC)
Historical Development
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2nd Millennium BC: Minoan warships
Fresco from Thera (1600 BC)
Historical Development
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Late 2nd Millennium BC: The Penteconter
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50 oars
100 feet long
Used as a
troop transport
The Penteconter
Attic black-figure
Dinos
(c. 550 BC)
Historical Development
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Around 800 BC: The Bireme
Attic bowl, Thebes (c. 735 BC)
Double the oarsmen
or halve the length?
Double the oarsmen or halve the length?
Historical Development
A first-generation
trireme?
Assyrian relief showing the evacuation of Tyre, 701 BC
The Trireme
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Probably developed in Phoenicia (and possibly Corinth) around 700 BC
Thousands built in Greece, Asia Minor, Egypt, and the Levant
Perfected in the Athenian triremes of the 5th century BC
Later Oared Warships
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Hellenistic Era
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Quadrireme, Quniquereme, …, 20er, 30er!
Carried large complements of troops and artillery
No longer used ramming tactics
Roman Era
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Relied on triremes and quadriremes
Developed specialized equipment to enhance the ships as
platforms for marine infantry
The Corvus
The Olympias Project (1982-87)
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The Goal: Design, build, and test an accurate working
reconstruction of an Athenian trireme from the 5th-century BC
The Team:
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Designed by classics
scholars, naval architects,
and rowing enthusiasts
Funded by the Greek
Ministry of Culture,
the Hellenic Navy, and
private donations
Built by a Greek shipbuilder at the Piraeus
An extraordinary exercise in experimental archaeology
Literary Sources
Histories of Herodotus and Thucydides
}  Oblique references to triremes in Greek
poetry, drama, and philosophical treatises
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Literary Sources
Histories of Herodotus and Thucydides
}  Oblique references to triremes in Greek
poetry, drama, and philosophical treatises
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“…and they came to a place where they could see from above a line
of light, straight as a column, extending right through the whole heaven
and through the earth…; another day's journey brought them to the
place, and there, in the midst of the light, they saw the ends of the
chains of heaven let down from above: for this light is the belt of
heaven, and holds together the circle of the universe, like the
hypozomata of a trireme. From these ends is extended the spindle
of Necessity, on which all the revolutions turn.”
~ Plato’s Republic
Archaeological Sources
Wrecks of ancient merchant ships
Kyrenia Ship (4th century BC)
Archaeological Sources
The Athlit Ram (probably 2nd century BC)
Archeological Sources
Athenian naval inventories
}  Relief fragments
}  Vases and vase
paintings
}  Coins
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Archaeological Sources
Ship sheds at the Piraeus
Archaeological Sources
Ship sheds at the Piraeus
And the Most Important Source…
…but only because of
global symmetry in
time.
Key Information
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Physical characteristics:
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Length and width of hull
(122 feet x 19 feet)
Shell-first construction
Wineglass-shaped cross section
Configuration of bow and ram
Stern and steering system
Number of oars (170 + spares)
Length of oars (9 or 9.5 cubits)
Spacing between oars (2 cubits)
Size and composition of crew
Removable mast and sail
Key Information
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Operating characteristics:
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Cruising speed (7-8 knots)
Turning radius
Positive buoyancy
Marginally stable
Vulnerable to high
seas
Beached sternfirst at night
Design: The Oarsystem
Did the ancient Greek trireme have three levels of oars?
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Impossibly long oars on the top level
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What about quadriremes, quinquerems, and 20ers?
Design: The Oarsystem
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Well-established alternative naming systems
A Scaloccio
Alla Sensile
Design: The Oarsystem
But a three-level
oarsystem
with all oars
of the same length
is feasible!
Design: The Oarsystem
The Lenormant Relief,
Athens (410 BC)
Askoma
Design: The Hull
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Accommodate 170 oarsmen at correct spacing
Shape consistent with all sculptural and pictorial representations
Stern configured for launching and beaching
Cross-section and construction methods consistent with all known
contemporary vessels
Length and width consistent with ship shed dimensions
Positively buoyant and stable without ballast
Hydrodynamic properties consistent with known cruising speed
There is only one solution to this problem
Hull Construction: Plank-on-Frame
Hull Construction: Shell-First
Hull Construction: Shell-First
Design: The Hull as Structure
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Sagging
Hogging
Bending & Shearing
Ship’s Weight
Buoyant Force
The Hull as Structure:
Role of the Keel
Splices
The Hull as Structure:
Keel Splices
The Hull as Structure:
Role of the Hypozoma
Design: Other Elements
Ram
}  Decks
}  Masts & rigging
}  Sails
}  Oars
}  Rowing
hardware
}  Steering oars
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The Finished Product
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Cost: Over $1 million
Built with modern tools and a few minor compromises on
materials and methods
Displacement:
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28 tons empty
46 tons manned and fully equipped
Power under oar:
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17 horsepower
(sustained)
110 horsepower
(in short spurts)
20 hp
motor
Sea Trials (1987-1994)
Sea Trials (1987-1994)
Results of Sea Trials
Stable under oar and sail
}  Highly maneuverable
}  Demonstrated
need for a highly
trained crew
}  Speeds almost
reached historically
attested levels
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8+ knots max
6 knots cruising
Shortfall could be addressed with
a few modest design changes
Conclusions
A three-level oared warship can achieve historicallyattested levels of performance.
}  Ancient Greek shipbuilders achieved:
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A deep qualitative understanding of nautical engineering
Superb shipbuilding skills
Modern science and engineering can inform our
understanding of history in uniquely powerful ways.