Tha's Cogs, Carracks n' Caravels; Well shiver me timbers what ship's a galleon then?
Was It a Galleon? Was it a Spanish Galleon?
This was the heading of the now famous newspaper article about the Stradbroke "galleon" by Isabel Hannah in the Brisbane Courier Mail of 1921. In this piece Isabel states that the man who found the ship in the Swamp in the early 1890's, Mathew Heeb who was "a shipwright" and a boat builder and that he said specifically  that the vessel was a ship and had a "high poop and forecastle".
This single piece of historic information actually answers the question "was it a galleon" because the high poop and forecastle was not a common characteristic of a galleon but makes the shipwreck in the 18 Mile Swamp more likely to be either a carrack or a caravel rather than a galleon.

However when people think of shipwrecks from the sailing era, from the golden years of sail driven exploration, they immediately think of galleons, particularly Spanish Galleon, but the reality is that most timber sailing ships we find as wrecks around the world's oceans were not galleons but various other styles of ship. Below I will  attempt to show the differences between the different types of ships, the periods of their prevalence, where and when they sailed the oceans and what they predominat uses for each style of ship were.
Is it a galleon?
Yes it is.
Whilst this image of a Spanish galleon does have a high poop and a forecastle the forecastle would not be described as "high".
Galleons, Spanish Galleons in particular, were built big to carry large amounts of goods or weapons long distances. Sailing qualities of galleons were compromised for size.
When people think of Spanish shipwrecks they tend think "galleon" but the reality is that there were many other types of ships used in the "Age of Exploration" by Spain and Portuagal as well as the other sea faring nations of that time. On this page I will discuss the Cogs, Caravels, Carracks, Lateeners, Galleys and Galleons which were all in use in this period.
The  Cog  was a northern style ship, clinker built usually with a poop and forecastle but not prominent. It was square rigged with a single mast but because the square rigged sail could be moved in relation to the the line of the keel and the direction of the wind the Cog and other early square rigged ships could sail even with the wind blowing at least abeam, something the lateen rigged ships could not do.
The  Carrack, left and below, with the combination of Lateen and square rigged sails handledwell and with its lateen stern sail could make reasonable head into the wind. It was the preferred style of ship for the early Ocean explorers. With a high poop and forecastle. From Heeb's description it is quite likely that the Stradbroke galleon is a carrack
It is possible, in fact likely, that the ship in the swamp is a Caravel. Whilst, generally, generally the caravel was used for trading close to shore and not the preferred vessel for long distance journeys it did have certain attributes which suited in-shore coastal exploration.
In my interview with Jim Bryce, who helped his girlfriend's father strip timber from the shipwreck in the 1920's, Jim states that the timber planking on the hull was "some kind of tounge and groove." This might suggest it was a clinker built ship as a caravel built ship has the planks flush and butted. He also said that there were no nails in it, that it was "dowled" that is trunneled (or tree-nailed) with no copper plate/sheath. The absence of copper sheathing makes it almost certainly a pre-Cook ship as, by the end of the 18th century virtually all ship's hulls were treated with copper sheet.
A  Galleon plows  the ocean
The historic development of  European ship design is generally considered to have come from the merging of two sources, the Northern style ships, basically from the Scandinavian nations, and the Southern style ships which can loosely be called Mediterranean.
Southern Styles
The historic roots of  southern ship designs are generally traced back to the Egyptian ships then through the ships of various seafaring nations such as the Cretans and Phoenicians to the Greek and Roman Galleys though the reality is that Egyptian ships do look a lot like Viking Longboats, other than they are mostly made of reeds.
The major change to Mediterranean ship design occurred around 1200 AD when the traditional lateen sails began to be replaced by square rigged sails.
The lateen sail is a triangular sail, generally carried in pairs, one sail fore and one sail aft designed to catch the wind on either side but keeping the same edge forward, the opposite of a square rigged sail. It was when the Mediterranean ships incorporated the square rigged sails of the northern styles that the real breakthrough in ship designs occurred.
From these emerge the carracks and caravels and then galleons of Spain and Portugal.
Southern ships were "caravel built" that is with planking butting flush.

Northern Ships
In the north the classic image of the Viking Long boat sums up the early northern ships, no real keel but with a fixed rudder or steering board, on the right side of the hull at the stern, called the "steer board"  hence "star board" star being steer.
The northern ships where "clinker built", that is with over lapping planks sometimes also known as ship lap.

Another distinction between north and south was the type of sail. The northern boats tending to have a square rigged sail, usually just one mast, whilst the southern ships usually had lateen sails, that is triangular sails, usually on a two masted ship with the larger sail at the fore.
Early English ships followed the northern fashion whilst Spanish and Portuguese followed the southern style. Eventually they both fused; by around the 15th to 16th centuries taking the best characteristics from both styles.
As ships became more and more used for naval fighting a small castle, for and aft, the forecastle and stern castle, was added to allow bowmen and then gunners to have a shooting platform. The advent of the cannon in naval warfare brought about the most significant changes to ship design as the weight and distribution of the cannon became critical to the shape and size of the ship. Ships became longer and the ratio of length to width changed from around two to one to being three or for to one. Thus one way of telling the age of an otherwise difficult to date hull is by this ratio.

As the role of the ship in the expansion of Empire, success in war and trade became more and more important a variety of functional designs for specialised tasks emerged. Ships suitable for exploration of rivers and bays; ships for carrying large compliments of soldiers, settlers, supplies and weapons and so on began to emerge. Thus we have the caravel, the carrack and the many styles of ships which appeared in the later 18th and 19th centuries.
accurate model of a Spanish Galleon. Note low  forecastle

To scale cross section of Spanish Galleon
3D image of Spanish Galleon cruising the Pacific Ocean in a nice passive mood.
Below: reconstructed and operational Caravel, note lateen sail at stern.
The terms 'lateen sail' derives from Latine, as the mid-eastern sailors on the Mediterriane were referred to at the time of the Crusades when styles mixed in the Med.  The fore and aft lateen was of more use when sailing (predominantly) east and west with prevailing winds north and south (thanks R Lewis)
The history and development of European sailing ships
Egyptian ship of about 2000 B.C.
Above: Caravel "Espirito Santo" which belongs to the Brazilian Navy.
Left is a slightly fanciful rendition of a 15th century  carrack with  exaggerated  poop and forecastle. Note how the forecastle is designed as a platform to suit military fighting applications
Above: A caravel, probably the Boa Esperança belonging to Portugal,home port at Lagos. Rigged with lateen sails but with no forecastle. (thanks Joao)
A Caravel

Left is an image of a fully functional replica of Columbus's ship the Santa Maria. As Columbus generally referred to the Santa Maria as a caravel it has been built as a caravel.
Not the planks on the hull butt up flush against each other and are not over lapped. Ships or boats with overlapped planks are called "clinker built" or shiplapped.

When they are flush as in the image of the caravel here the ship is called "caravel built".

This caravel is built of Mahogany due to the incredible durability which mahogany has. Where oak ship could only last a few short years in the tropical waters before rot and ship worm destroyed the hull; mahogany ships could last almost forever.
Cross Section of a Spanish Galleon
mizzen mast
fore mast
Main mast
The cog’s origins lay in Anglo-Saxon designs that were as invative and seaworthy as the Viking ships. When the Saxons conquored much of England trade expanded and the cog’s progressively improved and refined the efficiency of its rig, making it larger to increase cargo capacity, replacing the steering oar with a pintle-and-gudgeon rudder thus making further increases in size possible. Through all this, the cog retained its single mast and square sail, a keel on a flat bottom with flush-joined planking, straight stem and stern posts, and clinker upper planking. So successful was the cog that many features of its design, including the sternpost rudder and square sail, were widely adopted in the Mediterranean for use in conditions quite different from those in the Nrothern Seas. Eventually the most useful aspects of the cog's design melded with those features of the Mediterranian ships. This blending increased the possible size of the ship and enhanced its handiness. In the face of these design changes the "pure" cog dissappeared and gave way first to the hulk and then to the full-rigged ship. Similarly, the cog’s flat bottom, useful for loading and unloading in small ports with extreme tides, became irrelevant for large vessels as trade swelled in volume and as an increasing proportion passed through major ports with wharves and proper loading facilities. However the flat bottom of the cog, which enabled the cog to sit on the sand or mud at low tide and allowed loading and unloading in areas without proper ports remained in use for certain functions and was popular in the colonial time when good port facilities were not available. Captain Cook's barque Endevour had such a bottom and was ideal for exploring in shallow shoal waters. However  most shipping moved forward to fused designes and the first example of this is the Carrack.
CARRACK circ. 1470's
Viking Long Boats
These two historically accurate Viking long boats, or long ships, show the used of the square rigged sail.
Note the real Viking long boat is sailing with the wind hard on the port (left) side of the ship and the Vikings have turned the sail at a 90 degree angle to the wind. In the drawing on your left the sail in catching the wind full a' stern. This feature gave the Viking ships a great advantage. This advantage was carried over into the square rigged design of the Cogs
Early Northern StyleSailing Ship, the Cog
A 14th Century Cog.