Safety accessories

In short

A few simple accessories let you be seen, free yourself and signal a problem: a delayed surface marker buoy with its reel, a light, a line cutter, a whistle, sometimes a mirror or a sound signalling device. They are only useful if you carry them on every dive, can find them without searching and have practised using them. The required equipment depends on the type of dive and on local regulations: ask your dive centre or club.

Why it matters

A team surfacing far from the boat, a diver caught in fishing line, a group split by the current: these situations are rare but real. In each, an accessory weighing a few tens of grams makes the difference between an incident quickly solved and a long wait at the surface. A badly stowed accessory, on the other hand, can snag or get lost.

The delayed surface marker buoy

A delayed surface marker buoy (DSMB) is a long, brightly coloured inflatable tube connected to a reel or spool. Inflated underwater and released, it rises to the surface and marks the team's position during the ascent and stops.

When to deploy it

• on a drift dive or in a current, so that the boat can follow the team;
• when the team ascends far from the mooring or the planned point;
• when boats are using the site;
• according to the briefing: some centres ask for one buoy per team, others one per diver.

How to deploy it

1. Stabilise at the stop depth or slightly deeper, next to your buddy.
2. Check that no line runs around you or your equipment.
3. Unroll the buoy and hold the reel firmly away from your body.
4. Inflate it with a second stage, the inflator or a dedicated valve, depending on the model and your training.
5. Release it, letting the line run without blocking it, then reel in as you ascend.

The risks

• Entanglement: the line can wrap around an arm, a valve or a hose.
• Being dragged up: if the reel jams, the buoy can pull the diver towards the surface. Let go of the reel rather than be dragged up.

Deployment is learned with an instructor, first in a pool or in shallow water.

Lights

• Primary light: essential at night and on dark sites, useful by day to reveal colours and look into holes.
• Backup light: a second, smaller light in case the first fails; essential at night.
• Strobe or light stick: attached to the cylinder or the diver, it lets everyone be spotted at night. Prefer rechargeable or reusable models to single-use chemical light sticks.

Check the batteries before every dive and do not dazzle your buddy (see the guide on surface and night communication).

Freeing yourself and being heard

• Line cutter or knife: fishing lines and abandoned nets are a real danger. A line cutter with a protected blade is easier to handle than a large knife. It must be reachable with either hand.
• Whistle: at the surface, it carries further than your voice and does not tire you.
• Surface signalling horn: connected to the low-pressure hose, it makes a loud sound using air from the cylinder.
• Signalling mirror: in sunny weather, its reflection can be seen from very far away.
• Location devices: some divers carry a beacon or a waterproof radio; their use follows specific rules, so find out before buying one.

What is required or recommended

Mandatory equipment depends on the country, the setting (club, dive centre, independent diving) and the type of dive. In France, the Sports Code specifies the equipment divers must carry according to the conditions; dive centres often add their own rules. For a night, drift or offshore dive, a surface marker buoy and a light are in practice essential. The official sources listed detail these rules.

Where to attach them

• Always in the same place, so that you can find them without looking, even with gloves.
• Close to the BCD: nothing should dangle or drag on the bottom.
• Reachable with either hand for the line cutter.
• Backup light and buoy in a pocket or clipped to a BCD D-ring.
• Show them to your buddy during the pre-dive check.

Key takeaways

• Carry a surface marker buoy, a light and a line cutter on every dive that calls for them.
• Deploy the buoy while stable, line clear, and let go of the reel if it drags you up.
• At night: primary light, backup light and a light marker.
• Attach each accessory always in the same place, with nothing dangling.
• Practise with an instructor before you need them.

Further reading

The guide on surface and night communication explains how to use these accessories to signal; the current guide describes how a drift dive is organised. Illustrations of the equipment will be added from the guide image library.