Introduction
G. A. Robinson gives an account of harvesting abalone ("mutton fish") in deep water by the aboriginal tribes on the north coast of Tasmania, facing Bass Strait.
In placing thirty-one aboriginals on Swan Island, in a "state of security," he also records that "the Blacks would probably never attempt and might not succeed if they did attempt" the crossing from Swan Island to the mainland on their rafts ("catamatrans")
As Robinson considers the crossing extremely difficult, "a boat though well manned can scarcely make across," this still suggests considerable familiarity of the aborigines with their craft.

Also note:
1831 G. A. Robinson: The Aboriginal Rafts, Northern Tasmania.
Printed in The Hobart Town Courier, 22 January 1931, page 4.

G. A. Robinson at Bega & Twofold Bay, August - September 1844, in:
1797-1892 Michael Organ (ed.): Canoes of SE Australia.
Extracts from A Documentary History of the South Coast Aborigines, 1770 - 1850, Wollongong University, 1990, page 279.

SUPPLEMENTARY RESEARCH: Bamboo Rafts (?)

Franklin DC: Taxonomic interpretations of Australian native bamboos ... 2008.
- viewed 8th June 2014.

STUDY NOTES- Under preparation.
Aboriginal Rafts
The crossings of the straits between South East Asia and Australia, a distance of perhaps 90 kilometres, by the nascent-Aborigines provides a definitive benchmark in maritime history.
Such a voyage is only conceivable with the employment of considerable maritime skills, in the construction and management of their vessels, and a studied familiarity with the ocean environment.
Although it is likely that this was their longest voyage of relocation to date, it was probably not the first.

It is often suggested, admittedly with some ambivalence, that these crossings were either by log raft or by bark canoe, however, note that  no distinction is usually made between the tied-bark of the mainland or the more-seaworthy, rolled-bark design of Tasmania.
Given its antiquity and inherent seaworthiness, the log raft is clearly the most practical candidate.

A third possibility, that these were bamboo rafts, was noted, with considerable reservations, by D.C. Franklin in 2008:

A plausible but hypothetical case has been made that Aboriginal people could have reached Australia on bamboo rafts (Flood 1995, Bednarik et al. 1999).

(However...)

I have also been unable to identify any direct archaeological evidence from Aboriginal usage that B. arnhemica may have been in Australia for millennia.
Remains of bamboo have been detected in archaeological deposits in Kakadu National Park, but only in deposits no more than, and possibly much less than c. 800 years of age (Clarke 1988), page186.

- Franklin, D.C.: Taxonomic interpretations of Australian native bamboos ... 2008, viewed 8th June 2014.

For a substantial ocean crossing by a significant number of people, probably including the elderly and the young, it is questionable whether a bark canoe of suitable dimensions could be constructed.
Note that the vessel would also have to carry a store of freshwater, presumably fire, provisions, and a collection of tools and weapons, in addition to any twines or other materials that might be carried for repairs at sea.

While it is impossible to create an accurate picture of the forest resources of coastal South East Asia 50,000 years ago, it is probably safe to assume that there was a reasonable supply of timber available to ancient raft builders.
Their technology included fire and stone tools, known from the archaeological record, and, invariably absent, a variety of bone tools and rope or twine, woven from plant fibres.
Similarly absent from the archaeological record, and often overlooked, were a selection of wooden tools; not only used as shafts for axes, adzes, spears, or knives, but as levers and, importantly in this instance, as poles and/or paddles to propel rafts
The advantages of co-ordinated and collective manpower, and abundant time, should also be noted.

The local forest and the current technology would determine the variety and size of the timber harvested to construct a raft, and although a number of methods are possible, it is clear that larger logs, of the same species, would be more buoyant and structurally sound.
In construction, prime consideration would be given to selecting, or manipulating, logs that would provide the smallest seam between them, and the fixing of bindings.

The possibility of a major structural adjustment while afloat is a major advantage over any bark canoe; indeed, over any equivalent sized craft.
This was a feasible proposition given the likelihood that these voyagers, like Columbus (1492-1493), da Gama (1498), and de Queirós and Torres (1605-1607), travelled as a fleet or in convoy, maximising the chances of a successful voyage and the possibility of assistance while at sea.
James Cook's first Pacific voyage (1769-1771) in the Endeavour, is a notable exception.

Furthermore, once landfall was made, a large raft could be easily disassembled for other functions, particularly useful if reconfigured as smaller craft, more suitable in the new location.

As the prime method of propulsion was by various methods of paddling, these ancient mariners probably attempted to their voyages during benign conditions, although they may have also identified suitable rips, tidal flows, and winds, as advantageous.
The raft was manoeuvred by arm-stokes or by swimming, with small hand-blades or paddles (a pudding stirrer), or a pole, effective in shallow water and, although without a blade, also produces a considerable amount of thrust in deep water.
Throughout south-east Australia the Aborigines punted their canoes with the base of their fishing spears.

- Edwards (1972) page 31; Bradley (1788) in Flannery (1999) pages 54-55; Stokes (1846) pages 15-16.

At this point, it is highly unlikely, though not impossible, that propulsion was assisted the use of a "sail."
Any mechanism that could be said to be sail-like, was probably a structure of large fronds added to provide a shaded area for the crew, that incidentally provided assistance when the wind was suitably astern.

Mangrove rafts were still in use on the northern coasts at the time of European contact, but traditional craft had largely been supplanted by the relatively recent introduction of the dugout canoe from Melanesia.
On the Beagle's survey of north-west Australia in the 1840s, John Lort Stokes reported "The raft they use is precisely the same in make and size on the whole extent of the North-west coast," this wide dispersion and uniform design suggesting a craft of significant antiquity.

- Stokes: Discoveries in Australia, London, 1846, page
 
The raft of the north-west coast, or kaloa, is a unique double-decked design built from logs of the widely dispersed mangrove tree, and fixed with hardwood spikes.
While the hardwood spikes may have been the method of construction of the original rafts, it is just as possible to be a later development.
In the seventeenth century, Lionel Wafer observed a similar method employed by the raft builders of Panama- after being bound with Maho-Cords, the logs were and pegged through "with long Pins of Macaw-wood."

- Water, Lionel: A new voyage and description of the Isthmus of America. Ed.by G. P. Winship, Cleveland, 1903.
Quoted in Roberts and Shackleton: The Canoe, MacMillan of Canada, Toronto, 1983, page 6.
 
Crucially the double-deck design, whereby two triangular rafts are sandwiched together, with their bases opposed, is an example of substantial over-engineering, as would be expected when contemplating an inaugural voyage.
The design effectively doubled the buoyancy, without the need to procure larger logs, while retaining a narrower profile that was more sea-worthy and easily manoeuvred, than would be the case with a wider craft.
Maximising the structural integrity, the central logs are in contact with, and could be affixed to, both the two logs beside it, and the two below.
Furthermore, as the top deck was less prone to water-logging, if the voyage was extended, the lower layer could be jettisoned, or recycled, if it became damaged in any way.
In the extreme case of complete structural disintegration, the individual logs, as swimming floats, offered the last resort for self-rescue.
The illustration and photograph below clearly show the construction of small double-decked rafts.

It is generally accepted by maritime historians that the development of the raft substantially precedes any form of boat or canoe.
 
- Casson: Ships and Seafaring in Ancient Times (1994) page 7, Johnstone:The Sea-Craft of Prehistory (1989) page , Landstrrom: The Ship (1961) page 11.

Given the simplicity of design, the inherent buoyancy of log construction, the ability to carry large loads, and a recognised stability in a sea, a larger version of the double-decked kaloa is the prime candidate for the Aboriginal occupation of Australia.
In a global context, this a strong indication that, at least 50,000 years ago, rafts were firmly entrenched as the dominant water craft for the transport of communal groups, along with a suitable amount of provisions and chandler, in navigating large bodies of water.

Rolled-Bark and Reed Canoes - Tasmania
Upon landfall, it appears that the southward dispersal was largely inland, and into what was then  a possibly more tropical environment, and not around the east or west coasts.
Thus, water craft of southern Australia were subsequently either re-invented or reconfigured in response to the available resources.
This is undoubtedly the case for the aboriginals of Tasmania, whose antecedents had made the earliest of the ocean crossings and eventually occupied the the southern extremities of, as it was then, the continent.

Regularly cited as "bark or reed," the canoes of Tasmania, are a distinct design and unlike the tied-bark canoes of the mainland, see below.
While the materials varied with the region; stringy-bark (E. Obliqua) in the south, paper-bark (Melaleuca sp.) in the north-west and reeds in the east; the construction technique remained the same.

If bark, multiple strips of bark were rolled in the form a log, much as in rolling a cigar, and then bound tightly with twine or, if reeds, simply dried, aligned and bound to produce a single craft, able to be paddled by an individual as a float board.
The canoe was a composite of smaller bundles of bark or reeds lashed to a larger central keel with fibre cord, and tapered at the ends so that the bow and stern rose high out of the water.
Fire was regularly carried on a bed of clay and the canoe was propelled by a pole, paddle, or by a person swimming alongside.

- http://www.aboriginalheritage.tas.gov.au/canoes, viewed 9 October 2013
- Robinson, G. A.: Friendly mission : the Tasmanian journals and papers of George Augustus Robinson, 1829-1834.
Edited by N.J.B. Plomley. Hobart : Tasmanian Historical Research Association, 1966.

These canoes were known to travel across large stretches of open water (see Tasman in Muller 1898?), G. A. Robinson noted:

"Aboriginal leader Worrady recounted in 1831 that they would embark on long and dangerous voyages to islands as far as Eddystone Rock and Pedra Blanca, up to 25km off shore, stating that their catamarans was large, the size of a whaleboat, carrying seven or eight people, their dogs and spears.
The men sit in front and the women behind."

In design, the rolled-bark canoe is essentially in the form a three-log raft, with the timber logs replaced by similar sections of bound bark or, on the east coast of Tasmania, bundles of dried reeds.
The most famous example of three-log raft is the catamaran of Madras, known for its performance in the demanding surf on the east coast of India.

Similar reed craft were common across the Pacific, examples include the pora of Rapanui, the balsa of California's Seri Indians, and the cabiltto of Peru, and all known to be actively sea-going.
As these appear at some of the extremities of human occupation, after numerous significant water-crossings and variations in environment, it is probable that these were originally based on some knowledge of the the log raft, and re-configured with local substitute materials.

Tied Bark Canoes - East Coast Australia
In the south of the continent, aborigines, no doubt, often used a log, and occasionally several fastened together, in crossing rivers and narrow straits.
However, the availability of suitable timber was limited, and most likely these were broken limbs collected from the forest floor, that had cured for some time.
Henry Ling Roth (1899) noted, that "Eucalyptus wood is too heavy to float, and few Tasmanian woods have sufficient buoyancy to serve for rafts unless very dry."

The tied-bark canoe, with certain regional differences, was in wide use inland and on the coast of south east Australia.
Formed from one sheet of bark cut from a tree, with its shape simply enhanced with the ends filled with mud or bound with twine.
More sophisticated designs included internal struts and/or binding, some even moulding the shape in an external frame.

The vast majority of reports of Aboriginal tied-bark canoes indicate that the usual crew was two, but on some occasions, up to six; however this usually included infants or juveniles.
In a rare exception, John Oxley (1818) reported bark canoes "sufficiently large enough to hold nine men," but this was on an inland lake, and this simple craft was unlikely to be suitable for use in the open ocean. (Edwards, p 7-9)

As the European explorers travelled through the ocean tropics, before landfall, they would invariably encounter local fishermen or traders at sea in their indigenous craft.
While many accounts, like those around Sydney Harbour, strongly infer that the craft were used off-shore; significantly, reports of European sailors encountering mainland Australian aborigines at sea in tied-bark canoes are extremely rare.

Most significantly, a coastal panorama of Wallinga Bay, NSW, painted around 1825 by Robert Hoddle, includes an Aboriginal in a bark canoe, apparently, preparing to return to the beach through several lines of surf.

In response to a discussion about native canoes in 1826, Daniel Cooper wrote to the Sydney Morning Herald that he had witnessed Aboriginals at sea off the south coast of New South Wales of two occasions.

"In 1834 I saw the natives using the large canoes outside both Jervis Bay and Twofold Bay, and the large fish which were brought in by them clearly proved to me that their canoes must have been very buoyant and strong.
Anyone acquainted with the strength and tenacity of stringy-bark would not wonder that a primitive people without metal tools should use it for boats in preference to wood, which could only be hollowed out in a rude manner, and with immense labour."

- The Sydney Morning Herald, 30 June 1862, page 3.

Note that Jervis and Twofold Bays are deep-water ports with easy access to off-shore fishing grounds in benign conditions.

Francois-Edmond Paris, serving on the Astrolabe when it visited Jervis Bay in 1826, drew and described the local bark canoes, while questioning their sea-worthiness:

"Only at Jervis Bay, south of Port Jackson, did we see a canoe on the sand, 4 to 5 metres long, if however this name may be applied to a piece of bark tied at the ends (plate 112, fig. 1) and held open in the middle by flexible saplings, curved by a cord like a bow; this frail skiff had no form and could not have been able to travel very far.
We do not know how the natives succeeded in removing such large pieces of bark from the handsome trees which cover the region around their bay, where, in 1826, the English had called only briefly and had not yet established a settlement."

- Paris, Francois-Edmond: Essai sur la construction navale des peuples extra-européens, ou, Collection des navires et pirogues construits par les habitants de l'Asie, de la Malaisie, du Grand Océan et de l'Amérique, dessinés et mesurés par M. Paris.
Arthur Bertrand, Paris, 1841-5, Plate 112, descriptive quote page 106.

Paris was to rise to the rank of admiral, and was later appointed as the director of the national maritime museum of France.

Dr. Stan Florek has claimed, apparently on archaeological evidence of occupation, that " some variants of Queensland seafaring bark canoes must predate dugouts because they, or their earlier prototypes, allowed visiting offshore islands (e.g Whitsunday Island, Great Keppel Island) from at least 8,000 years ago."

- Stan Florek: Nawi- exploring Australia’s indigenous watercraft, Australian National

Stan Florek presented a paper at the conference ‘Nawi – exploring Australia’s indigenous watercraft,’ held at the Australian National Maritime Museum (31 May – 1 June 2012). - See more at: http://australianmuseum.net.au/BlogPost/Science/Tentative-Chronology-of-Indigenous-Canoes-of-Eastern-Australia#sthash.wOGeLt8J.dpuf

Maritime Museum (31 May – 1 June 2012)
http://australianmuseum.net.au/BlogPost/Science/Tentative-Chronology-of-Indigenous-Canoes-of-Eastern-Australia, viewed 16 September 2013.

However, note the relatively recent date, and that these islands, while technically "offshore," are inside the Great Barrier Reef and not subject to the intense storms and large swells generated in open ocean conditions.
Furthermore, there appears no reason why these journeys could not have been carried out on rafts.

Although the Tasmanian Aboriginals were known to travel across large stretches of open water (Tasman in Muller 1898), this was not in tied-bark canoes, but rather rolled-bark or reed craft, see above.

Some variants of Queensland seafaring bark canoes must predate dugouts because they, or their earlier prototypes, allowed visiting offshore islands (e.g Whitsunday Island, Great Keppel Island) from at least 8,000 years ag - See more at: http://australianmuseum.net.au/BlogPost/Science/Tentative-Chronology-of-Indigenous-Canoes-of-Eastern-Australia#sthash.GDWINtev.dpuf

There were some sightings of aborigines of Northern Australia and the Torres Strait Islands in the open ocean, however these reports are of dugout canoes, some with outriggers, or sophisticated sewn bark canoes.
The dugout had been assimilated much later from visiting Macassan trepang fisherman, and the sewn canoe was a significantly later development from the Pellew Islands.(edwards, page 10)


It is generally noted that Aboriginal bark canoes become waterlogged after prolonged use (Edwards, page 9) and their structural rigidity was minimal. 
- Bradley (1788) in Flannery pages 54-55.
While perhaps not a serious problem for short term use in enclosed waters, the result of such a vessel being swamped in the open sea was potentially disastrous.

It is probable that the tied-bark canoes of inland and coastal Aborigines, like the rolled-bark or reed canoes of Tasmania, were either re-invented or reconfigured as the needs arose across a diverse range of environments.

The principle advantage of the tied-bark canoe was its simple construction with a most basic of tool kits, a stone blade, fire and twine.
Only slightly less important, was its extreme light weight that facilitated easy transport between bodies of water, particularly useful along the coastal zone.
This feature was integral in the development of the highly sophisticated birch-bark canoe of North America.

Sewn Bark Canoes - North Coast Australia.
Awaiting content.

Dugout and Bark Canoes - North Coast Australia.

Some variants of Queensland seafaring bark canoes must predate dugouts because they, or their earlier prototypes, allowed visiting offshore islands (e.g Whitsunday Island, Great Keppel Island) from at least 8,000 years ag - See more at: http://australianmuseum.net.au/BlogPost/Science/Tentative-Chronology-of-Indigenous-Canoes-of-Eastern-Australia#sthash.GDWINtev.dpuf

The aborigines of Northern Australia and the Torres Strait Islands were regularly sighted in the open ocean, usually in dugout canoes, some with outriggers, or in sophisticated sewn bark canoes.
The dugout had been assimilated from visiting Macassan trepang fisherman, and the sewn canoe was a significantly later development from the Pellew Islands.

-Edwards, page 10.