A lot of people have never even heard of lateen sails, but their invention changed the world. Lateen sails are arguably one of the most important inventions of ancient history.
But what even are lateen sails, how do they work, when were lateen sails first invented and why were they so revolutionary? We answer all those questions, and a lot more besides, in this ultimate and comprehensive guide.
Living on our sailboat for 5 years has given us a keen interest in maritime history. We’re massive sailing nerds, in other words.
The lateen sail is actually something we’ve written about several times, partly because it’s the precursor to the triangular sails that almost all sailing vessels use today, and partly because we’re… massive nerds.
The lateen is so interesting because it unlocked one critical new ability that changed sailing forever – and with it transformed the worlds of travel, trade, exploration, and warfare. Join us as we explore what makes lateen sails special and just why they were so important to the ancient world.
Table of Contents
- What is a lateen sail?
- Why was the lateen sail so important?
- How can boats sail upwind?
- Modern day lateen rigs
What is a lateen sail?
A lateen is type of rig used on sailing vessels, featuring a triangular sail held up on side side by a long wooden spar called a “yard”. The yard mounts at roughly a 45-degree angle to the mast, running forward and aft.
The very first examples of the lateen sail crop up in the Mediterranean around the 2nd century AD, but the lateen didn’t become popular until around the 5th century BC.
Don’t be fooled by that slow burn popularity, though – the lateen would go on to change the world, and remain relevant for over a thousand years.
It was arguably one of the most important technologies of ancient history, and in many ways the spiritual successor to the Bermuda-type rigs seen on modern sailing vessels like sloops.
The lateen was one of the first rigs to use aerodynamic sails pointing forward and aft, rather than big, square sails designed to act like parachutes and flying laterally across the beam. Why that distinction is so important, we’ll see in a moment.
Another rig operating on similar principles and originating at a similar time in the Mediterranean was the settee. The settee is essentially a lateen with the front corner cut off, giving it a quadrilateral (four-sided) shape instead of triangular. Settees were seen on working Arab dhows right into the 20th century.
But now, the really interesting question – why was the lateen sail so important, historically speaking?
Why was the lateen sail so important?
Sailing has been around for an almost unbelievably long time. We know for sure that people were sailing over 6,000 years ago, because we’ve found clay tablets and inscriptions depicting sailing boats and crew, complete with primitive rigs and square sails.
6,000 years is a fairly long time in terms of civilised human history – for a frame of reference, writing wouldn’t be invented for another 600 years; Woolly Mammoths would still walk the earth for another 2,000 or so (no, really).
In the Encyclopaedia Brittanica’s timeline of the most important technological discoveries, sailing is right near the start – in between iron and irrigation. We’ve found completely preserved boats that are over 10,000 years old.
But that’s just the tip of the iceberg. Some historians and anthropologists think that people in ancient Asia had to have been voyaging island-to-island as long as 25,000 years ago, crossing distances that would appear to necessitate sail propulsion.
The kicker is that for the overwhelming majority of those 25,000 years, people could only sail downwind.
They could steer a little to either side of downwind, but if they wanted to travel upwind or across the wind they had to row – or make clever use of the tides and currents. This naturally had a huge determining impact on the direction countries explored in and the nations they could trade with.
Sails in those days worked like parachutes – they were just big bags designed to catch as much wind as possible.
The lateen changed all that: being rigged fore-and-aft, and having that yard across the top to control the draught and shape of the sail, they could point their sails into the wind, not just across it, and generate lift in the same way a bird’s wing does. The yard also meant they could tack the sail – move it from one side of the boat to the other.
The upshot of this is that the lateen rig could tack upwind – and across the wind, along a coastline and back again. Suddenly, people could transport vast quantities of goods (or troops) in almost any direction – not just downwind – and turn around and come back again.
Its effect on the world, naturally, was transformative – even if over the course of several hundred years.
Mediterranean powers, such as the Romans, made extensive use of the lateen in both war and peace from at least the 5th century (its name even comes from the word “Latin”), but Northern European nations didn’t truly catch on to triangular sails until around the 14th century.
Nonetheless, sail would remain the dominant means of trade, exploration and foreign invasion for most world powers right through to the 19th century.
Even today’s modern pleasure yachts almost exclusively use a fore-and-aft rigged style, such as a Bermuda rig, and owe a lot to the lateens of old.
How can boats sail upwind?
A triangular sail like that found on a lateen works a lot like the wing of an aeroplane in flight.
It has a curved surface, like a half-teardrop. As air strikes the curved surface of the sail, it naturally forms an area of low pressure across the convex outer surface, and an area of higher pressure across the concave inner surface.
This happens because the air literally has further to travel on the outside of the curve; it has more space to spread out. Approximately the same number of air molecules are flowing over both the front and back of the sail, but the ones at the back are packing into the curve and creating a pocket of denser air.
Pressure always wants to flow from high to low; thus, the boat slips forward into the area of low pressure, relieving the high pressure behind, even though that’s upwind… against the very force it’s using to propel itself.
This action is assisted by the keel, which is longer than it is wide – and therefore resists sideways movement, known as leeway, more than forward motion. The keel incorporates a heavy weight, called a bulb ballast, to counteract the forces acting on the sail above.
In our aeroplane-in-flight example, the keel is also acting like the other wing of the ‘plane. Because water is much denser than air, the keel naturally has to be smaller than the sail above.
Sailing vessels cannot sail directly into the wind, but modern performance yachts can get to within about 40 or 35 degrees.
A sailing vessel can still travel directly upwind, they just have to claw their way up by tacking backwards and forwards across the wind, in a zig-zag pattern, at the closest angle their boat allows.
You may hear sailors talk about velocity made good (VMG) – referring to the velocity at which a boat is moving towards her destination, regardless of how she is travelling through the water and across the ground in the process of getting there.
For example, I could be tacking across the wind at a 45-degree angle and making 5 knots over the ground, but if my destination is directly upwind and I’m always moving towards it at a 45-degree angle, I am actually only progressing towards it at 3.5 knots (this is my VMG).
That’s assuming I make no leeway at all, which obviously I do. But you get the picture – tacking upwind can take a long time, especially once current and tide come into play.
Modern day lateen rigs
While the lateen was largely out of fashion by the end of the 19th century or so, it retained pockets of popularity well into the 20th century – such as the Gundalows of Maine and New Hampshire.
Sailors liked that the entire sail and yard could easily be dropped for maintenance, and to pass under low bridges in the tidal waterways.
Similar rigs, such as the lug rig, were seen on fishing vessels right into the 20th century as well.
The lateen was also heavily adopted by the Dutch and became the bezaan rig, which in turn eventually morphed into the Bermuda rig that was almost universally adopted by small sailing vessels by the end of the 20th century.
As such, you could argue that the lateen’s DNA is present in almost all modern-day sailing boats, just minus the heavy yard!
Lateens fell from commercial use by the end of the 20th century, but a handful of reproductions are still built and sailed – such as this lovely example.
Conclusion: Lateen Sails
The lateen represented a huge leap forward not just in sailing technology, but in the ability of ancient people to explore, trade, travel long distances and (unfortunately) invade each other.
That’s because it gave ancient people the ability to sail in almost any direction – upwind, downwind, or back and forth across the wind – say, along a coastline, from port to port and back.
Before the lateen, people could only sail in the direction the wind was blowing, give or take a few degrees. This severely hampered the usefulness of the boat as a means of transport – it could carry huge loads for great distances, but only in one direction.
The lateen changed all that. Its fore-and-aft-rigged design and aerodynamic shape allowed it to point upwind and generate enough lift and drive to propel the boat forward at 40 or 45 degrees off the wind.
It also introduced the ability to tack the sail, moving it from one side of the mast to the other. This in turn meant lateen-rigged boats could tack across the wind and even make progress towards a goal that was directly upwind, given time and persistence.
Naturally, this had huge military consequences – like every pawn on a chessboard suddenly getting queen moves. Manoeuvring became a decisive tactical factor in many of the great naval battles of the Age of Sail.
The lateen rig eventually gave rise to the Bermuda rig, which became more or less totally ubiquitous on small sailing vessels by the end of the 20th century. Almost all modern pleasure yachts use a variation of the Bermuda rig, such as a sloop rig.
In conclusion the lateen was a hugely important and influential development; arguably one of the most important inventions of the ancient world, and certainly one of the most important sails of all time.
The post Lateen Sails – What Are They And Why Are They Important? appeared first on Two Get Lost.
