A Divers Guide To Surface Marker Buoys & DSMBs

The Divers Guide to Surface Marker Buoys & DSMBs came about because for years now there seems to have been confusion about the actual terminology, not that it matters, but some pedants will pick you up on it. There is also a lot of choice out there when it comes to maker buoys. What is right and wrong can be very subjective, but there are some broadly agreed principles that will help you make informed choices when purchasing or using your marker buoy.

This guide will explain the different types, colours, features and why you may want one over another. This is not gospel, but I started diving in 1996, and have had more than my fair share of the good, the bad and the downright ugly marker buoys over this time. Some of these relics thankfully have been retired to the Dive Box in the sky.



This Divers Guide to Surface Marker Buoys includes:

  • What is a surface marker buoy?
  • What terms are used to describe marker buoys?
  • What is a Surface Marker Buoy?
  • What is a Delayed Surface Marker Buoy?
  • Surface Marker Buoy Colours
  • Delayed Surface Marker Buoy (DSMB) training
  • Choosing a Surface Marker Buoy

Let’s dive in.


What is a surface marker buoy?

Delayed surface marker buoy, SMB for short or safety sausage is all pretty much inflatable tubes (most of the time). This is the simplest description, a brightly coloured tube that lets the surface know there is someone holding it, or underneath it on a line, there are two primary kinds.

The first type is towed for the whole dive (SMB) and allows a dive boat, boat traffic or shore support to track the movement of a dive team under water.

The second type is deployed from underwater before the end of the dive and is often used to aid a controlled ascent. They also let the boat or shore know where you are ascending from a recreational or technical dive with or without decompression. These are called delayed surface marker buoys (DSMB).

What terms are used to describe marker buoys?

There are several terms all used to describe maker buoys. The generic term is SMB, however this does not totally accurate on all counts. Terms that are used include:

  • Safety Sausage
  • Blob
  • Delayed Surface Marker Buoy (DSMB)
  • Surface Marker Buoy (SMB)
  • Decompression Buoy
  • Signal Tube


What is a Surface Marker Buoy?

SMB stands for surface marker buoy and technically refers to any device that would mark your position visually on the surface. A delayed SMB or DSMB is a device that’s inflated underwater and sent to the surface so you can find your position, without having any trouble with water. You would use this to make a safe ascent, help you stay safe on the surface and be visible from above.


What is a Delayed Surface Marker Buoy?

Delayed Surface Marker Buoys are split into two main categories: open ended or sealed. An "open-ended" Surface Marker Buoy is like a bag, with three sides that have been sealed at one end to allow you fill it up from an alternate air source. Deploying a DSMB is by inflating it with your alternate is the simplest approach. This is where many divers start, however, as their skills improve many move to oral inflation of the DSMB.


What Surface Marker Buoys colours are there?

A DSMB or SMB are not life-saving dive gear, but it does serve a similar function. As such the colour of these devices must be appropriate to attract attention. There are no regulatory requirements for SMB’s which means any colour can work. Over the years, orange has become standardised within the scuba diving community for dive-by-dive use.

During low visibility or during lower light conditions, yellow may provide better contrast against water surfaces. The downside to this is that in certain circles yellow has become the colour of choice to signal that the dive bellow has a problem, needs more gas etc. This use of using yellow for emergency is not always known, or adhered to, but in more advanced/technical diving this was the norm for a long while. But consider this when you choose an SMB.


Delayed Surface Marker Buoy (DSMB) training

Boats and currents are two common factors associated with many dive sites. Boaters don't always recognize that divers may cross paths, so it's important to have a delayed surface marker buoy (DSMB) ready before you ascend back up from your underwater adventure! If there is no other visual reference for where they end up after their trip below water - which can happen especially if the weather gets rough or worse yet involves some type of rip tide--a person without one will be lost unless someone spots them via boat light come nightfall because these buoys stay afloat even when attached deep within coral reefs around various parts.

To enrol in the DSMB Diver course, you must be at least 12 years old and have completed a PADI Open Water Diver certification. You now know the purposes, and you'll learn about common types of DSMB along with the reels used to control them. During the two training dives, you'll practice:

  • Preparing and stowing your DSMB and reel.
  • Deploying the DSMB from a stationary position and from mid-water.
  • Swimming while towing a DSMB and managing the reel and line.
  • Making a safety stop using the DSMB line.

Besides your basic scuba equipment, you'll need a DSMB and reel. Make sure you drop into the dive centre to ensure you get the best advice on which DSMB is best for your diving.


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