THALIS O MILISSIOS – IMO 5357800

ex JOSEPH HENRY – 1909-Built Historic Cable-Laying Steamship and Floating Museum

THALIS O MILISSIOS is one of the most historically significant preserved ships in Greece and an exceptional survivor from the earliest years of twentieth-century submarine communications.

Built in the United States in 1909 as JOSEPH HENRY, the steel cable-laying steamship was constructed by Newport News Shipbuilding and Drydock Company in Virginia for the U.S. Government.

After almost four decades of American service, she was transferred to Greece in 1947 and renamed:

THALIS O MILISSIOS.

For the following 36 years, the vessel played a crucial role in developing Greece's telecommunications network, laying and maintaining submarine telephone cables connecting the islands with the mainland.

Withdrawn from service in 1983, she narrowly escaped scrapping and was eventually donated to the Aegean Maritime Museum in 1991.

Today THALIS O MILISSIOS is officially recognised as a Floating Museum and is preserved at the Park of Maritime Tradition at Palaio Faliro.

Even more remarkably, the Aegean Maritime Museum identifies her as:

the world's oldest surviving cable-laying steamship still retaining its original steam engines, as well as the oldest vessel on the Greek Ship Registry.

Vessel Details

Current Name: THALIS O MILISSIOS

Original Name: JOSEPH HENRY

IMO: 5357800

Type: Cable-Laying Steamship / Museum Ship

Flag: Greece

Built: 1909

Builder: Newport News Shipbuilding and Drydock Co., Virginia, USA

Original Owner: United States Government

Transferred to Greece: 1947

Greek Operator: T.T.T. / Telegraph, Telephone and Postal Services; later OTE

Current Custodian: Aegean Maritime Museum

Official Status: Floating Museum

Gross Tonnage: 842 GT

Length Overall: 51.26 m

Beam: 9.77 m

Hull: Steel

Propulsion: Original steam machinery preserved

Withdrawn from Commercial / Cable Service: 1983

Donated to Aegean Maritime Museum: June 1991

Current Location: Park of Maritime Tradition, Palaio Faliro, Athens

Preservation Status: Preserved museum vessel.

Built as JOSEPH HENRY

The vessel was constructed in:

1909

at:

Newport News Shipbuilding and Drydock Company

in Virginia.

Her original name was:

JOSEPH HENRY.

The name honoured the influential nineteenth-century American scientist whose work in electromagnetism contributed fundamentally to the development of electrical communications.

The vessel was ordered for the:

United States Government

and purpose-built for work associated with undersea telecommunications cables.

An Early Cable-Laying Steamship

Long before:

satellites,

mobile networks,

fibre-optic systems,

and modern wireless communications,

international and island communications depended heavily on:

submarine cables.

Cable ships were specialised vessels able to:

carry long lengths of cable,

lay them accurately on the seabed,

recover damaged sections,

and undertake repairs at sea.

JOSEPH HENRY belonged to this technologically important but relatively small family of specialist vessels.

Transfer to Greece – 1947

Following the Second World War, the United States transferred the vessel to Greece in:

1947.

She was handed over to the Greek:

Telegraph, Telephone and Postal Services – T.T.T.

which later developed into the telecommunications organisation:

OTE.

At the same time, JOSEPH HENRY received her new Greek name:

THALIS O MILISSIOS – ΘΑΛΗΣ Ο ΜΙΛΗΣΙΟΣ.

Named after Thales of Miletus

The new name honoured:

Thales of Miletus,

the ancient Greek philosopher, mathematician and scientist.

Thales is frequently associated with some of the earliest recorded investigations into:

electricity,

magnetism,

astronomy,

and natural philosophy.

The name was therefore particularly appropriate for a ship dedicated to telecommunications technology.

Connecting the Greek Islands

For more than three decades, THALIS O MILISSIOS worked to connect:

the Greek islands

with:

mainland Greece.

Her principal duty was the laying and maintenance of:

submarine telephone cables.

This work took the vessel throughout the Aegean.

For an island country such as Greece, these undersea communications links were essential to the development of a modern national telephone network.

A Working Ship for 36 Greek Years

The vessel remained in active Greek service from:

1947 until 1983.

That means her Greek operational career alone lasted approximately:

36 years.

By the time of withdrawal she was already:

74 years old.

The technological world around her had changed almost beyond recognition since her construction in 1909.

Withdrawal – 1983

THALIS O MILISSIOS was finally withdrawn from active cable-laying service in:

1983.

A new vessel equipped with considerably more advanced technology replaced her.

At that point, OTE intended to:

scrap the historic ship.

Had that plan proceeded, an irreplaceable survivor from the earliest period of maritime telecommunications would have disappeared.

Saved by the Aegean Maritime Museum

The newly established:

Aegean Maritime Museum

intervened to save the vessel.

The museum recognised not only her Greek telecommunications history but also her international significance as an extremely rare surviving steam cable ship.

Following years of preservation efforts, OTE formally donated THALIS O MILISSIOS to the museum in:

June 1991.

Restoration

After acquisition, specialists carried out a detailed survey to determine how the historic vessel could be preserved.

The restoration was supervised with the involvement of:

Lloyd's Register of Shipping

Hellenic Register of Shipping

and:

Greek Merchant Marine Inspection Service.

The objective was not simply to keep the hull afloat.

The project aimed to preserve the vessel as closely as possible to her authentic historical form.

Original Steam Machinery Survives

This is perhaps the most important fact about the vessel.

The Aegean Maritime Museum describes THALIS O MILISSIOS as:

the oldest cable-laying steamship in the world that still preserves its original steam engines.

That makes the vessel technologically important far beyond Greece.

Many preserved historic ships survive only after:

major machinery replacement,

conversion,

or extensive reconstruction.

THALIS retains a direct mechanical connection with the era in which she was built.

Oldest Vessel in the Greek Ship Registry

The museum also states that THALIS O MILISSIOS is:

the oldest vessel registered in the Greek Ship Registry.

In 2026 she has reached approximately:

117 years since construction.

Official Floating Museum

The Greek State formally designated the vessel as a:

Floating Museum.

Her preservation also received international recognition.

In:

1998

Aegean Maritime Museum founder George Drakopoulos was honoured by the:

World Ship Trust

for his contribution to saving THALIS O MILISSIOS.

Maritime Tradition Park

Today the ship is preserved at:

Palaio Faliro

within the:

Park of Maritime Tradition.

She forms part of an extraordinary concentration of historic Greek vessels that also includes:

Battleship GEORGIOS AVEROF

Destroyer VELOS

Trireme OLYMPIAS

EUGENIOS EUGENIDIS

and:

EVANGELISTRIA.

Together these vessels represent very different periods of Greek naval and maritime history.

Piraeus Connection

THALIS O MILISSIOS also has an important connection with the wider Piraeus maritime area.

During her working career she repeatedly operated from Greek telecommunications and repair facilities, while preservation and maintenance work has also brought her into the Piraeus ship-repair environment.

A documented drydocking took place in the:

Vasileiadis dry dock

in 2008.

The ship therefore belongs not only to the national maritime heritage collection but also to the historical industrial landscape of Piraeus.

PiraeuShips in 2020

PiraeuShips published the dedicated:

THALIS O MILISSIOS – IMO 5357800

entry in:

August 2020.

The original database correctly recorded:

842 GT

1909 construction

Newport News Shipbuilding

Greek flag

and:

JOSEPH HENRY

as the former name.

The expanded profile, however, reveals why the ship is far more important than those basic specifications suggest.

A Survivor from Another Technological Age

THALIS O MILISSIOS was built before:

the First World War,

commercial radio broadcasting,

modern aviation,

electronic computers,

satellite telecommunications,

and container shipping.

Yet the hull and original steam machinery survive more than a century later.

Few ships represented in the PiraeuShips archive offer such a direct physical link with the beginnings of modern communications technology.

PiraeuShips Record

THALIS O MILISSIOS represents one of the most historically important vessels preserved in Greece. Built by Newport News Shipbuilding in Virginia in 1909 as the U.S. Government cable ship JOSEPH HENRY, she was transferred to Greece in 1947 and spent the following 36 years laying and maintaining the submarine telephone cables that connected the Greek islands with the mainland. Withdrawn from active service in 1983 and initially threatened with scrapping, the ship was saved through the intervention of the Aegean Maritime Museum and donated to the institution in June 1991. Today she is preserved at the Maritime Tradition Park in Palaio Faliro as an officially designated Floating Museum. At approximately 117 years of age in 2026, THALIS O MILISSIOS is described by the museum as the world's oldest surviving cable-laying steamship still retaining its original steam engines and as the oldest vessel on the Greek Ship Registry. The PiraeuShips record therefore documents not simply an old ship, but an internationally significant survivor from the formative age of submarine telecommunications.

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