Flagpole mechanics: external halyard, internal halyard, revolving truck

A flagpole looks simple, but it contains a small mechanism. The way the flag is hoisted determines whether it can fly at half-mast, how much noise the pole makes and how vulnerable it is to vandalism. Circular VR 2015/37 of the Flemish Government includes a working hoisting mechanism and ropes in good order as part of the quality standards for public buildings.

External halyard

On a pole with an external halyard, the halyard runs from the bottom of the pole up to the pulley at the top and back down the outside. The flag hangs from the halyard on snap hooks or clips. At the bottom, the halyard is tied off on a cleat. This is the simplest system, and parts are easy to replace.

A drawback is that the halyard can slap against the pole in the wind, which can be heard at night. A counterweight or tensioner keeps the halyard tighter.

Internal halyard

On a pole with an internal halyard, the halyard runs inside the pole. At the bottom there is a hatch, often with a lock, behind which the halyard is tied off. An internal halyard does not slap against the pole and makes it harder to steal the flag. That is one reason why associations, municipalities and businesses often choose an internal halyard. Circular VR 2015/37 points out that isolated poles are more exposed to vandalism and theft.

Pulley and revolving truck

At the top, the halyard runs over a pulley. A revolving truck turns with the wind, so that the flag and halyard wrap around the pole less. On a banner pole, an arm keeps the flag spread out. Some arms turn as well.

Telescopic pole

A telescopic pole has no halyard. The flag is fixed with rings to the top section, and the pole is brought to height by extending the sections. The flag therefore cannot fly at half-mast. In mourning, a black ribbon at the top is a common solution, as the protocol service of the FPS Home Affairs describes for poles that are too short.

Tilting base and ground sleeve

A tilting base allows the pole to be lowered to replace the pulley, the halyard or the finial, without an aerial work platform or ladder. A pole in a ground sleeve can be taken out whole. Both make maintenance safer. More on this is in the guide on flagpole safety.

Half-mast and mechanics

To fly a flag at half-mast, a pole with a halyard and pulley is needed. According to the protocol service of the FPS Home Affairs, the flag is lowered so that a space the height of the flag remains free above its upper edge. A second halyard or a mark on the halyard can show the right height in advance. More on this is in the guide on half-mast.

When the flag wraps around the pole

In shifting wind, the flag can wrap around the pole and get stuck. Circular VR 2015/37 recommends lowering and raising the flag if needed to shake it loose. A revolving truck, a banner arm or a tighter halyard reduce the chance of this happening. More on freeing a jammed halyard is in the guide on flagpole repair.