Naval planners in the early 16th century had a problem. None of them knew that they were 'naval planners,' but that was not a problem. They knew their assignment: To build warships for the King of England, or the Most Serene Republic of Venice, or at any rate for someone. Their problem was that that some years earlier the French had applied bell making technology to heavy guns, with spectacular results.
The new generation of artillery, bronze muzzle-loading cannons and culverins, were lighter than conventional bombards, safer and more reliable, and immensely more powerful. On land they rendered all existing fortifications obsolete and brought about a new type of fort, the trace italienne, built low and massive behind a ditch – the prototype of 18th century Vauban forts, and ultimately of fortifications up to and including present day firebases.
At sea the new heavy guns were equally problematic. Medieval naval warfare followed a combined arms doctrine, a mix of slow but sturdy and high-built round ships, similar to large transports and functioning as mobile castles, and faster, low-built rowing ships, galleys and smaller 'barges,' that served roughly as seagoing cavalry. The rowing ships had offensive punch (including putting troops ashore), while the big round ships provided defensive strength and logistic support.
Both types could be adapted to carry heavy guns. Galleys carried them above the prow, 'keel mounted,' serving as a super-ram or (more often in practice) to give a blast at 'cloth burning range' across the deck of an enemy ship just before boarding it. Lofty round ships were suddenly far more vulnerable to direct galley attack. Soon after 1500 a partial solution was found: The big ships could also carry heavy guns mounted on the lower decks, positioned to provide all-round defensive fire (though firing directly forward remained a problem). Henry VIII's Mary Rose, build in 1509, sunk in 1545, and recovered from the seabed of Portsmouth in 1982, was an early example of the type.
Mounting a dozen or so bronze great-guns aboard a carrack was very expensive, and while the resulting ship could stand up to galley attack it was inflexible and could not take the initiative against much more maneuverable galleys. Planners looked for alternative ways to bring heavy guns into play at sea, and hit on a couple of related solutions. The ship pictured above, the English 'galleass' Hart, built in 1546 – by no accident soon after the loss of the Mary Rose – was one of them.
In overall design Hart, like her near-sisters Tiger, Bull, and Antelope, is a fairly large sailing ship, with four masts as was common at the time, but longer and narrower than usual and without the lofty fighting 'castles' fore and aft. Her relatively cut-down prow allows her to carry heavy guns firing forward over her galley-style beak, and she carries a row of medium-caliber guns along the broadside of her upper deck above oar ports on her lower deck.
Her mission was to serve as an anti-galley escort. Though slower than the French galleys she was intended to fight she could at least force them back with her heavy bow guns. And if the galleys swarmed in, even though she lacked the high fighting castles of conventional big ships her powerful secondary armament could give them a very hot reception.
These 'galleasses' performed very well in skirmishes against galley squadrons. The Venetians, about the same time, built galleasses of quite different design (oversized galleys, converted from merchant galley hulls) but similar mission, and they did an impressive job of shooting up Turkish galleys in the opening stages of the Battle of Lepanto in 1571. The Venetian galleass type is the one usually mentioned in modern books, though it turned out to be a dead end largely because of geostrategic developments that sidelined the Mediterranean in the 17th century.
Galleasses of the English type, however, had a big future ahead of them – and not one their designers originally had in mind. Probably they were not an English invention, most likely originating in Spain or Portugal, though Henry VIII built one big ship of the type, called simply the Great Galley, as early as 1515. Though effective against galleys they were pigs under oar-power – but swans under sail. And their broadside secondary armament, intended for defense against swarming galleys, turned out to be highly effective in offense.
So larger versions abandoned the lower-deck oars, replacing them with more broadside guns, until the secondary armament became the main armament. This variant type got a variant name, galleon, and ended up as the ancestor of the classic broadside-armed sailing man-of-war. (Some smaller models retained oars well into the 18th century – in an unusual Hollywood concession to accuracy the Black Pearl in 'Pirates of the Caribbean' is fitted for sweeps, as was Captain Kidd's rather similar ship, Adventure Galley.)
No, I am not recommending space galleasses for your constellations of combat spacecraft, though aerial galleasses might fit nicely into those flying-ship settings for graphic novels. But the evolution of the galleass, from anti-galley ship to the ancestor of the frigate and two-decker, is a good example of the impact of changing technology and requirements. Space warcraft of a future era may well develop over time in a comparable way, designed initially for one mission and gradually tranformed to perform a very different one involving different primary weapons and tactics.
This blog has a known weakness for the 16th century, particularly its women, real or fictitious.