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Castle Drawbridge: Purpose, Design & History

One of the most effective defensive features of a medieval castle was the moat — a wide, water-filled ditch that completely surrounded the fortress to keep enemies at bay. While the moat provided strong protection against invaders, it also posed a challenge: how could the castle’s residents enter and exit safely? The ingenious solution was the drawbridge, a movable bridge that allowed access when needed and could be raised to block intruders.

Castle Drawbridge - Parts of a Medieval Castle

Castle drawbridges were typically made of wood and had to be long enough to span the width of the moat. In the early medieval period, drawbridges were quite basic and operated manually. As castle design evolved, later medieval drawbridges became more sophisticated, using mechanisms like pulleys and winches to raise and lower the bridge more efficiently.

To operate the drawbridge, ropes—and later, stronger chains—were attached to a rotating device called a “windlass,” which was usually located above the gatehouse passage. This allowed guards to control access quickly in times of attack or retreat.

Drawbridge

Castle Drawbridge Definition

A castle drawbridge was a heavy, movable wooden bridge that spanned the width of a castle’s moat or defensive ditch. It served as the main entrance to the castle and could be quickly raised to block enemy access during an attack. Most man-made moats were approximately 12 feet wide and 30 feet deep, creating a significant barrier that the drawbridge had to cross.

Defending the Castle

The drawbridge was essential for allowing the inhabitants of a medieval castle to enter and exit when the castle was surrounded by a moat. When raised, the drawbridge acted as a powerful defensive barrier—cutting off easy access and leaving the castle completely enclosed by water. This made it extremely difficult for attackers to reach the gates or breach the walls.

Medieval Moat & Castle Drawbridge - Parts of a Castle

The Castle Gate and Its Defenses

The main gate of a medieval castle was typically a solid wooden door, often reinforced with metal strips for added strength. It sat flush against the entrance walls, forming the first line of defense. As castle design evolved, a gatehouse was introduced—an enclosed structure built around the entrance to provide extra protection for this vulnerable area. In later periods, additional outposts known as barbicans were constructed in front of the gatehouse to further fortify the castle’s main entry point.

Castle Gate

Quick Defensive Response

The drawbridge could be raised quickly in the event of a surprise attack, making it nearly impossible for enemy soldiers or siege weapons to reach the castle gates. While the moat acted as a physical barrier, it relied on the drawbridge for practical access and defense. To enhance protection during these critical moments, a heavy wooden or metal portcullis—a spiked gate—could be dropped rapidly to block the entrance while the drawbridge was still being raised. This combination of defenses helped secure the castle during sudden assaults.

Castle Portcullis - Parts of a Medieval Castle
Castle Portcullis

Castle Drawbridge History

Early medieval drawbridges featured a simple design and were operated entirely by manpower, requiring people to manually raise or lower them. In some cases, damaged drawbridges were destroyed and rebuilt. As technology advanced, later medieval drawbridges became more sophisticated, using a system of ropes—later replaced by stronger chains—and pulleys to make raising and lowering easier and more efficient. Large or very heavy drawbridges often used counterweights to assist in raising and lowering, as the chains and pulleys alone couldn’t handle their weight. In some cases, the portcullis—a sturdy wooden gate reinforced with metal plating—served as a counterweight, helping to balance the drawbridge mechanism and making it easier to operate.

 

Chains Pulleys

 

Portcullis Drawbridge Counterweight
The Portcullis was commonly used as a counterweight for the Drawbridge

How Did a Castle Drawbridge Work?

In later medieval times, the drawbridge operated by tilting upward as it closed, pulled by thick chains. As castles grew larger, their entrances needed to be wide and sturdy, which made the drawbridges bigger and much heavier. These advanced drawbridges, introduced around the 14th century, were also called “bascule bridges.”

The term bascule bridge comes from French and refers to a type of movable lifting bridge that uses a counterweight mechanism to balance its weight. Bascule drawbridges required a carefully designed counterbalance system so both ends of the bridge moved in opposite directions smoothly.

Weights were added to assist this movement, and often the portcullis—a metal-grilled gate positioned just behind the drawbridge—served as an effective counterweight. This ingenious mechanism helped castle defenders raise and lower the heavy drawbridge efficiently and securely.Parts of a Medieval Castle – The Drawbridge

 

Portcullis - Parts of a Castle
Castle Gate with Portcullis

Castle Drawbridge Fast Facts

  • Modern drawbridges are also known as “Bascule Bridges” and were introduced in the 14th century
  • Weighted counterbalances were added to heavy drawbridges to help lower and raise them
  • Some later drawbridges used the castle’s portcullis as a counterweight
  • A “Bascule” drawbridge was raised by “Gaffs” (lifting arms)

Castle Portcullis of Medieval Castle

Drawbridges Working Parts

  1. Gaffs and Rainures – held counterbalance Beams in place
  2. Trunnions – helped the drawbridge turn
  3. Windlass – The mechanism that lowered and raised a drawbridge

A Portcullis could be quickly raised

 Castle Drawbridges – Did you Know?

  • Alnwick Castle in England used counterweights and a Portcullis system for its castle Drawbridge
  • Helmingham Hall in the UK has two 16th-century Drawbridges that still work!
  • Drawbridges could be quickly raised in a surprise attack by the gatehouse guards

Visit Helmingham Hall Drawbridge

helmingham hall working draw bridge

You Can See a Working Drawbridge at Helmingham Hall


Alnwick Castle Drawbridge

Alnwick Castle Drawbridge - Castle Parts

See a Drawbridge at Alnwick Castle

Castle drawbridges were just part of a system of complex defense systems that were built into later medieval castles, please explore our castle moat, barbican, and Gatehouse articles to get a better understanding of these castle parts which will build on your knowledge of Castle drawbridges.