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[Tutorial] Fortifications of the Sailing Age

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Tutorial: Forts – types and features

history, construction, equipment

Regarding all the questions for forts lately, I've decided to make a tutorial on fortifications. As this is not exactly my most dearest theme, I'll most likely make only this one on forts. So if you have questions on this one, put them into THIS thread now - thanks!

PART I – definitions, types and history

A fort (fortification or fortis lat. – “strong”) is a defensive military installation build to protect the people inside and/or a strategically important place or resource. Fortifications have been used through the entire history of warfare and their appearance has changed accordingly.

As a fort is constructed at a fix location and cannot be moved it has to fit perfectly into the role of defending whatever it shall defend

– No two shore batteries will look the same and no two castles are built in the same way.


Castletimeline von HMSCentaur auf Flickr

If you want to build a fort you have to ask yourself two things: what’s it for and when was it built?

Every fort will also mirror the latest developments in siege technologies at the time it has been created. A good example for this is the medieval castle keep – this part of a larger castle had already been used by Irish monks in the first century in order to protect the people by simply making it possible to sit a siege or a raid out – when the first catapults became strong and precise enough to damage those castle keeps, the architects decided to construct round castle keeps rather than angular in order to provide less target-area and to make the rocks glance off the walls when hitting them.

Castles became more and more vulnerable with every improvement there was made in gunpowder weaponry. The first answer to this was the construction of additional turrets and casemates in the 15th century. But especially turrets quickly turned out to be insufficient against fieldpieces.


WallsTimeline von HMSCentaur auf Flickr


Bastion2 von HMSCentaur auf Flickr

Subsequently they were replaced by bastions (or bulwarks) in the 17th century. This marked the beginning of the star-fort-techniques.

These projections of the regular fortified main walls could be hollow in order to house additional troops or equipment or solid in order to withstand more damage. Their steep angles made it impossible for regular fieldpieces to be positioned in a manner that could allow bastions and main fortifications to be attacked at the same time – additionally, the bastions made it possible for the defenders to cover the main fortifications without creating blind angles. At first, those bastions would augment the already existing castles.

However, the construction of ideal star-forts (or Trace Italienne) would soon revolutionize military architecture.


bastion von HMSCentaur auf Flickr


indeal coverage von HMSCentaur auf Flickr

Star-forts with their relatively low, but massive and angled walls would be constructed in order to provide the necessary protection for their own artillery that would be housed in higher casemates. Casemates are bunkers that protect the cannons inside by giving away as little target area as possible while hiding most of the equipment behind massive walls or the ground in case the casemate would be constructed on the ground level.

A good example of a star-fort-principle would be when a harbour would be completely engulfed in a Trace Italienne, protecting the fleet within and making it possible to withstand attacks from sea or from the land.


tracie harbour von HMSCentaur auf Flickr

Edited by Horry

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PART II Design details, building features


Embrasure von HMSCentaur auf Flickr

This part, as well as part III will focus on a fort that would be either completely constructed during the late 18th century or at least maintained and operated around that time. As you’ve read in part I, the fortifications had to adapt to the new standards in siege-weaponry.

A prominent example for this would be the embrasures. Originally, embrasures would be long, vertical holes in the defensive wall or tower with a small alcove behind it where the archer could repair his bow and store the arrows and that allowed to fire in a ballistic curve. Embrasures of the 19th century are designed for muskets and similar firing weapons. Most of them would be “key-hole-embrasures” that allowed for a wider angle to aim and shoot.


CASEMATE01 von HMSCentaur auf Flickr

Another important feature of our fort would – of course – be the defensive artillery. The cannons would be not too far away from the gun-powder magazine and positioned in a manner that would cover the most likely areas for an attack against the fort. The cannons would be aligned in so called batteries – series of cannons of the same calibre that would allow for a continuous bombardment of the enemy. Typically there would be between 10 and 25 guns in a battery, depending on the calibre. More guns would be technically possible but of no good use as the fog from the fired shots would take most of the aiming sight.


batteries 01 von HMSCentaur auf Flickr

Batteries would be positioned behind reinforced, low embrasures and normally featured regular gun carriages (“lafette”) that would also be used on ships of the time. This allowed for hot guns to be replaced by unused and for a repositioning of the cannon.


Trace italienne von HMSCentaur auf Flickr

Many batteries, including those at shores or harbours, would be protected by a casemate (probably ancient Greek: “chásma”= crevice). A Casemate is a complete emplacement, a fortified and specially armoured area for the cannons. It features thick walls and a stable roof. Casemates of the 18th century would be positioned in or under the bastion. In an ideal Trace Italienne the Casemate would be on top of the ground bastion (or star) but under the first level bastion. If the Trace Italienne features more than one bastion on top of the ground level, there could be casemates under every level up to the citadel.


Asjustment carriage 01 von HMSCentaur auf Flickr

Despite the frequently shown and popular Lego turning turret for the cannon, this technique was very uncommon until the later 19th century, when regular cannons would be replaced by full-grown artillery that would be too heavy to be carried, anyway.

Later and bigger bastions could feature casemates that included cannons on an adjustable carriage. These cannons had a higher percision and firing rate thanks to a movable carriage under the cannon that could be moved by a hoist. In order to quickly replace a damaged carriage or cannon the hinge for the rail and the carriage could easily be lifted off the construction.


Citadel von HMSCentaur auf Flickr

The citadel is the strongest part (and most of the time the smallest) of the fort. The citadel will most likely house the commander of the fort and the quarters of the officers. It has its own entries and batteries as well as an own armoury and ideally an additional cargo area and a well. Many citadels would have a semaphore-tower.

Some parts of fortifications remained the same over the centuries as they are essential for the operations conducted in the fort: an own supply of fresh water from a river but ideally from a well is a basic requirement. The safer the well is the better. All the rooms and installations for entertaining a standing garrison have to be in such a fort: quarters, officers’ quarters, a kitchen, a canteen, an armoury, an infirmary, detention cells, a smithy, a small shop, a laundry and a chapel as well as a small tavern.


Postern von HMSCentaur auf Flickr


Postern 1 von HMSCentaur auf Flickr

In order to get safely to any part of a bastion that is under attack one would use a network of posterns. These roofed or embedded, narrow accesses and corridors can be found next to or inside walls and lead to every important section of the bastion. Not only do they provide cover against enemy fire but they also conceal the movements of the bastion garrison as it is very well possible to get from the citadel to the outer walls without exiting the postern network.


blockade offset von HMSCentaur auf Flickr

In order to protect that network against intruding enemy forces, there normally are blockade offsets at all key junctions and at the entries to important areas. These simple pairs of grooves at both walls would be used to cant blockade beams and fill the gaps with even more blockade material. If everything else fails, the blockades can still be set on fire.

PART III Equipment

As individual the location and purpose of a fort would be, as different would be the equipment used. However, some of the rooms and machines used in forts are often or always the same.

Designated areas for the different ranks would be a normal thing in any military installation. There would be quarters for the commanding officer and a dining room for him. The second officer in command would get his own quarters, as well. In bigger garrisons there could be enough room to give the other senior officers their own quarters, too. The junior officers would, just like on ships of the time, be housed together in small sleeping areas.

The non-commissioned officers and the soldiers would be housed in barracks that are located near the most important parts of the fort: the entries, the batteries and the weapon holds.

In bigger forts there would also be designated canteens. In smaller forts, the soldiers would eat in their barracks. Thus, the kitchen would traditionally be located near the barracks and beside the food storage (a place that would be guarded at all times as it also holds the alcohol).

The infirmary would be consistent with the medical standard of the late 18th century: beds for wounded, a crude surgery-room, a quarantine-area for people that would be infected with contagious disease.


Hot rounds von HMSCentaur auf Flickr

Especially in Spanish shore batteries (in the late 18th century also in British and French installations) there would often be an oven near the batteries in order to prepare hot round shots – these would be scorching cannon balls made from iron or stone that would be put with care into the cannon and shot at attacking vessels. The hot cannon balls could easily enflame the sails, the dry wood of the hull or even the powder hold. However, in order to avoid setting off the propelling charge too early, there would be a wet stopper made from cloth put between the propelling charge and the hot cannon ball.

The gunpowder magazine would be either underground or in the very middle or the most secluded part of the fort in order to avoid getting hit during a battle.


Semaphores von HMSCentaur auf Flickr

A semaphore would be in any fort that will get in contact with ships or other installations or settlements that have semaphores – Semaphores are optical long range communication systems that were perfected in the late 18th century – they feature either coloured flags or large arms that can be positioned differently in order to relay certain messages or single letters. The message would be received by the next semaphore and re-transmitted again until it reaches its destination.

Defensive procedures against invading forces would be a part of any fort. The famous boiling oil would still be spilled on the enemy soldiers but could now be distributed through a complex network of gutters that would often be hidden in order to lure more soldiers into the trap.

Some of those gutters could also serve another purpose when filled with burning oil – they would proof to be effective firewalls, especially against attacking cavalry or soldiers carrying mortars.

Edited by Horry

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I love your tutorials! This is a great source for anyone trying to build a Lego fort. Keep up the amazing tutorials! :thumbup:

I really enjoyed your introduction on the evolution of how forts are structured, very interesting. The prolonged recoil piece looks like a great feature.

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Thanks, Hiawatha!

Apart from some pictures missing, this tutorial is now finished.

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Since you added on, I like the semaphore design. :thumbup: I've never seen one made out of Legos. That would be a great touch.

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In your casemate picture you show the guns facing out of one hole but they would be separate as enemy shells could easily get in and blow

the interior fort up. Also the bastions are generally in more of a arrow head shape usually. Moreover commonly the forts were generally in pentaganol shapes.

However this is a good and well detailed guide for making Fortifications.

This is a simple model demonstrating the bastions and the shape.


Yes this has no outworks on it but it shows a nice citadel.

This is Tilbuby fort in Essex England. This has some nice outworks like all the ditches and smaller gun batteries.


Edited by venios

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It is awesome to see how much knowledge about forts and their development throughout the ages you have. Fantastic work!

Although I meant stone castles started with round towers, later on it changed to square towers because the round towers created dead angles.

I love this tutorial, I will look back often if I need inspiration while creating harbour defences. :pir-sweet:

And you might be interested in Dutch star forts as well which are still present today:


The fortifications around the Dutch city Naarden.


Fort Bourtange.

As you can see, these fortifications occupy a rather large area. These areas also provided space for water pumping, grain and sawing mills to keep the fort independent.

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This is a really cool thread Horry. I can't believe I missed it! Expect this to be...


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This tutorial has just been updated with better picures and and three additional sub topics (adjustable carriage for casemates, posterns and blockade offsets)

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