Surface marker buoys are manufactured on-site. There are several different shapes and colours and can be bespoke or standard in size. Used as a signal marker for the diver to surface to, they prove a useful tool to skippers or onlookers to identify where divers are located in the sea.

Divers also use marker buoys as ascent tools. By attaching a reel line and inflating it slightly under water, the buoy rises to the surface of the water and denotes where the diver will appear.

There are three types of marker buoy available. The first is ‘out of gas’. This informs the skipper that the diver it out of air. When the skipper sees this they know to send down another cylinder of air, as surfacing quickly is not an option for the diver. ‘Co2 out of gas’ buoys do the same job, but use Co2 and built in firing mechanism, rather than air from the divers cylinder, to inflate the buoy under water.

The second type of buoy is ‘open ended’. This design has a restricted throat, so once it blown up it does not deflate. This is the most basic buoy design.

The third option is a ‘self seal & dump bag’. When this buoy is inflated under water it expands and self seals preventing air from escaping. As the buoy gets closer to the surface it may become over inflated and the built in pressure dump valve can be activated to release excess air. This prevents the buoy from exploding.