|The Mayflower II, the only ship in this article I've ever been on.|
You’re all gamers, and you know how seafaring in RPGs is depicted. It’s right out of Hollywood movies of the 18th and 19th centuries, classic Age of Sail tech. To a degree, this is understandable: medieval and Renaissance depictions of Arthurian and Biblical legends put folks in clothing, armor and weapons that would’ve fit in perfectly in contemporary culture. Moreover, filmmakers have budgets, and cinematic ships are almost always drawn from the pool of replica Age of Sail vessels out there.
This is reflected in gaming: ships are often depicted as huge, with 19th century cannon, ship’s wheels, sleek keel:beam ratios and all the trappings of the Age of Sail.
But we do know a lot about those earlier vessels. Want to do it right? Ditch damn near every movie you saw.
First off, ocean-going medieval vessels are small. The largest of them topped out at 200 tons, their accommodations could charitably be described as “spartan,” and they weren’t overwhelmingly seaworthy. They didn’t hold that many sailors, nor that many provisions – the navigational standard was to coast hop. Check out some of these links for examples of cogs, and carracks, caravels and fluyts that replaced them in the late Middle Ages and Renaissance eras. Take the Mayflower II above, a Renaissance-era fluyt. Being a Plymouth-area native, I've been aboard her several times. Imagining over a hundred passengers AND their livestock AND their stuff AND the crew on that teensy vessel, for two months yet in the North Atlantic autumn, just blows my mind.
Secondly, the science of shipbuilding hadn’t evolved very far. The fad for medieval European shipbuilding was for very high “castles” both fore and aft, quite suitable for the boarding tactics of the time and reminiscent of land fortifications, and which survives in the nomenclature of today’s “forecastle.” As cannon became common, they got jammed onto these top-heavy ships in appalling numbers and in appalling sizes – stability calculations being centuries in the future – and as you can imagine, an all-too-frequent occurrence was overburdened ships just toppling over and sinking on the spot.
Thirdly, they were a lot fatter than you imagine. Remember that ship deck plan you downloaded from that gaming site? It’s almost certainly crap. The keel:beam ratio (translation for you landlubbers: how long it is vs. how wide it is) runs as much as 7:1, which is about what you expect for 1870s extreme clippers that couldn’t possibly carry armament or a military crew and could do only one thing well – sail in a straight line, very very fast. I don’t say it isn’t useful to the designers of gamebooks, who can jam three grid plans of a 7:1 ship onto a single sheet of paper. It just bears no resemblance to reality.
The ratio for medieval ships were much more often along the lines of 3:1, and even as chubby as 2.5:1. This made for a craft that could haul more cargo, and could handle rough seas better, but it doesn’t look very 19th century.
A number of innovations hadn’t yet been invented. Smaller ships (such as cogs) were steered with tillers, just as you’d see on modern-day pleasure boats, or with large and inefficient steering oars. This didn’t work very well when ship sizes grew, and the whipstaff was invented – only in the 16th century. (The modern day ship’s wheel wasn’t invented until the 18th century.) The familiar anchor shape you think of wasn’t invented until well into the 1800s: medieval anchors didn’t have shanks, and the arms were straight instead of curved. Stern-mounted rudders weren’t common until well into the Middle Ages.
(By the bye, all of this refers to European seafaring, with which players are likely to prefer for aesthetic reasons. Chinese and Arabic seafaring of medieval times were much more advanced.)
I’ll touch on pirate ships, a major topic of gaming sail. Contrary to popular belief, there isn't a particular ship design called "pirate ship." Pirates used just about any hull they could get their hands on, although they favored sloops for their maneuverability, speed and ease of repair. Far more often than otherwise, these ships were usually small. This flies in the face of Hollywood, which favors large replica vessels and broad decks onto which you can pack a satisfyingly large cinematic battle as well as cameras and tech crew, but there you have it.
As to that, Spanish treasure galleons were very seldom used as pirate vessels; they could pack a whopping lot of men, but they were ponderously slow and needed outright shipyards for maintenance, something unavailable to most pirates. When galleons were used by pirates were in full scale assaults by outright fleets, more along the line of amphibious invasions than the normal run of piracy, and those assaults were things of legend that happened once or twice a decade.
Deckplans? That’d be a bit of a problem. NO library will have deckplans for a 17th century ship or earlier smaller than a third-rate (about the size and armament of a USS Constitution-sized heavy frigate), for that matter: the earliest sloop deck plan that has been uncovered so far dates from 1717.
A book I own and strongly recommend is Deane's Doctrine of Naval Architecture, published by the Naval Institute Press. Sir Anthony Deane was a prominent naval shipwright of the 17th century, and the Doctrine was written at the request of his patron, Samuel Pepys (the famous diarist, who was at the time the First Lord of the Admiralty), to explain ship design and building to the educated layman. Among other things, the book has exhaustive statistics of every ship on the Royal Navy list in 1670, and I mean exhaustive – I can crack the book open and give you for every possible rate (and where listed, for each one of the ships in the Royal Navy) the length and number of every single scrap of rigging, how much it cost to completely rig or provision the ship, how many guns and anchors they had, every possible dimension ... to a degree that would blow the mind of the most anal dungeonmapper alive.
In particular, using Deane's stats and given the range of guns found on pirate ships of the day, the heaviest pirate ships would be around 90' by the keel and 28-29' by the beam (for a 40-gun ship that could man around 200 men), and generally getting no smaller than a 4-gun smack that could man about 30 men and measure around 44' by the keel and 11-12' by the beam.