Diver SMB – The basics of diving surface marker buoys

A diver SMB is a fundamental part of scuba gear. It is one of the most important pieces as its main purpose is to provide you safety. In short, it helps you get spotted at the surface and picked up by the dive boat.

When deployed, surface marker buoys indicate that there are divers below, alerting boats to stay clear, leaving you enough space to surface safely. Alternatively, when it comes to drift diving, the boat will be able to identify your heading and make its way to you at the end of the dive.

For those of you who are new to drift diving it is where you dive with the current and the dive boat will come and pick you up rather than you returning to the boat like a normal dive. You can be really at the mercy of the sea with this type of diving, but it can be completely safe and fun with the right precautions and having an experienced dive guide or instructor who knows the sites well.

In this post we are going to discuss and breakdown all the important features and uses that DSMBs and SMBs have and why they should be one of the first pieces of equipment you buy as a diver.

 

What are diving surface marker buoys?

For those who are new or maybe haven’t had much experience, an SMB is a surface marker buoy and a DSMB is a delayed surface marker buoy.

Surface marker buoys (SMBs) basically look the same as a delayed surface marker buoy (DSMB), which is not very helpful when trying to buy one. A nickname for them is safety sausage and it is basically because it is a long tube with some source of inflation whether that be a tub you blow in like a balloon, or an opening to which you can use your alternate air source to purge in air.

The main difference usually to look out for, is that the surface marker buoys can be in various shapes with the dive flag red and white markings, but can also be in long tube shape in various colours, usually these are oral inflation only and made from a thinner material as they are designed for emergency use. They are often shorter and easily fit into a BCD pocket. In some locations it is expected to tow a dive marker for the entire of the dive.

Delayed surface marker buoys (DSMBs) will usually only be in the long tube shape style and may have oral inflation options and a bottom opening for you to inflate using an alternate air source. Some diver DSMBs are designed in a way that the opening seals itself once inflated.

 

What is a surface marker buoy used for?

A surface marker buoy is used to show that a diver is below. It alerts anyone at the surface to exactly where you are in the water. Diver SMBs are any kind of inflatable device which will float on the surface. They are popular with shore dives, as then they can be seen and help navigate boat traffic away from the divers. You may also inflate a surface marker buoy once you surfaced from a dive, say if you were too far away to swim back to the boat to signal them to come and pick you up.

Scuba divers take with them underwater a reel or spool. When you begin to ascend or if you need to contact the surface you can attach the DSMB to your reel and inflate it so it bobs up to the surface. When you start to ascend and begin your safety stop you send up your DSMB and hold onto it with line from your reel or spool so boats in the area know you’re there to either stay away or to come pick you up.

Often you will find diver SMBs in four colours: yellow, pink, red and orange and in some countries the colours can mean a few things. It’s best to check with your dive shop or tour provider when traveling. As an example, in England yellow means emergency.

Generally, you should never be more than 5m away from your own marker and boats should never get within 15m of an SMB or DSMB, therefore allowing a 10m buffer zone. However, this distance can vary depending on local regulations.

 

Do I need a diver SMB or DSMB?

We would say, yes, and would very much advise you to invest in one. A surface marker is one of the best signalling devices. In most places with channel and drift diving it is required to carry a diver SMB. Your dive guide or instructor will definitely have one. If, however, you plan to dive somewhere with strong currents, for your own peace of mind and safety, we recommend having your own diver SMB or DSMB. Do practice deploying it whenever you have a chance. Once carrying and using your SMB turns into a habit you will be ready to use it in any situation, including a real emergency.

On that note, here are some great SMBs and DSMBs available that we recommend. Depending on how much money you wish to spend, you can also get upgrades and some features that may be useful to you. On permanent surface marker buoys you may have pockets to put spare parts in. Or a light attachment for night diving. You can even have different reels and webbing deployment systems which we will discuss in more detail further into this post.

 

Different types of surface marker buoys and how to choose one?

Generally, you can categorise DSMBs into open-ended, self-sealing and fully closed.

 

Pocket buoys (open ended)

The pocket buoy is great as a beginner SMB as it is very affordable and easily fits in your BCD when going for a dive. It is an open-ended buoy that can be inflated with the use of your alternate air source. All you have to do is insert your alternate air source in the opening at the bottom, send it up to the surface and wait for your safety stop and the boat then to collect you.

It has a length of 152cm so it is nice and long in case of waves. It comes in pink and orange, both colours have been proven to be very visible from far. This one only weighs 0.33lbs and you can fit it in your pocket or attach to your BCD with the clip. You have an elastic cord to secure it neatly. It has a D-ring, to which you can attach your finger reel or WDS.

Pros: it is the most compact, easiest to deflate and most economical DSMB. However, it is open-ended and must be held underwater slightly to keep it inflated and risen. At the end of the dive simply tip the buoy over to empty the air, roll up and stow. You can use this marker for deployment under water too so it works both as a SMB and as DSMB but as we have mentioned it doesn’t close so its best to deploy shallow as then you can control it.

 

Basic compact open-ended buoy

Similar to the pocket buoy, this is one of the most popular amongst divers around the world. The Surface Marker WDS comes with the webbing deployment system, which is the ideal method to send up your diver SMB from your safety stop (discussed later in this post). It comes with its own carry pouch. The carry pouch can be attached to your BCD with the aid of a clip and additionally secured with the D-ring at the bottom. The pouches are all oversized. You can easily access your SMB during the dive and it can easily be stowed after the dive.

One of the nice features of this SMB is that when you do send it to the surface from your safety stop, you don’t have to worry about reaching the surface and spilling. The design of the lower restrictor and the weight of the WDS system will ensure that this part of the buoy always remains underwater. Thus, when the buoy reaches the surface and you don’t have any tension on the WDS, it will lie flat, but fully inflated on the surface with air inside. When you pull down the WDS the buoy will come upright, the boat will see you and you can continue doing your safety stop. On the surface, you simply have to tip over the buoy, empty it out, roll it up with the WDS stowed in the lower half of the SMB. And that will easily fit back into your pouch.

This SMB is yellow on one side, orange on the other side. The orange side you see clearly on bright sunny days. The yellow side is clearly visible on days when it is slightly overcast or where the light is deteriorating. With the two colours you have maximum visibility in any conditions.

 

X-Marker (self-sealing diver SMB)

The X-Marker is a compact self-sealing SMB. The self-sealing baffle at the bottom opening of the buoy acts as a one-way valve and seals the air inside the buoy. This type of diver SMB will remain fully inflated until you release the air by pulling on the overpressure valve toggle.

The X-Marker is 145cm long and 15.5cm wide. When inflated, this product will remain fully inflated on the surface. This has the added advantage that if you need to signal for help to the boat you can pull this out of the water and wave it a little bit higher so the boat can actually see you.

You can inflate your buoy by placing your alternate air source in the opening at the bottom of the buoy. The loops are long enough that you can pull them out of the way completely. On the way to the surface, the buoy will vent air from the overpressurisation valve. Once you finish your dive and you want to deflate the buoy all you have to do is pull on the toggle on the overpressurisation valve and the buoy will deflate.

The X-Marker comes in a variation of colours – orange, pink or a yellow&orange combo. At the top of the buoy you have reflective tape for even better visibility.

 

Surface Marker PRO (self-sealing diver SMB)

The surface marker PRO is one of the largest surface marker buoys. It is 175cm long and 21cm wide.
The top of the buoy has reflective tape on both sides. This helps for better visibility day and night with reflecting the sunlight as well as any artificial light. It also has a little pouch here at the top for a light stick. You can just drop a light stick in there and attach that securely to the handle at the top.

The handle at the top can also be used by decompression divers if they need to send a slate up to surface support. They can clip that slate onto the handle here and the surface support team can then read what the issue is.

The volume of this buoy is about 20l, which means it has a lift capacity of 20kilos. Which means it can also double up as a lift bag in an emergency and it can be pulled out of the water with the handle here.
This is a self-sealing buoy, which means once the air enters the bottom of the buoy through the opening down here the buoy will seal itself and the air will remain trapped inside the buoy. It will vent itself on the way to the surface from the overpressurisation valve. And once on the surface, when you finish the dive you can release the air by pulling the toggle here.

 

Fully closed (sealed DSMB)

This is a fully closed surface marker buoy – there is no opening at the bottom. It has a low pressure inflator valve which you can inflate via your BCD low pressure inflator. Simply couple your low pressure inflator with the SMB, inflate and send it to the surface. It will not lock on. It will decouple itself automatically. You can also inflate it via the oral valve. You simply push down on the valve and inflate it orally.

This DSMB has a length of 120cm. The small size and volume allow for quick and easy inflation underwater and on the surface.

On the way to the surface, the buoy will vent from the overpressure valve. Once you finish the dive, you simply pull on the toggle to release the air.

This buoy is used by rebreather divers, who do not wish to use an alternate air source to inflate their surface marker buoy.

Snorkelers can also use it as a flotation aid and rest on it.

 

Personalised diver SMB

One of our personal favourite features of the SMBs and DSMBs by Surface Marker is that you can personalise them. You can have a custom diver SMB with your name printed on it, making it easier to distinguish yours from anyone else’s. You can add any letters or your name or dive club name onto them and the print is really durable and long lasting.

 

Where to buy a surface marker buoy?

The readers of Dive into Life get a 10% discount at Surface Marker. Simply use the following code at check-out:

diveintolife10

 

How to deploy a diver SMB?

We have briefly discussed the various ways you can deploy your diver SMB. Now let’s go into it in a bit more detail!

One of the easiest methods is oral inflation or with the use of the low pressure inflator. To do this, disconnect the low pressure inflator from the BCD and connect to the oral inflator nozzle. Then we push&click the nozzle and it will inflate quite quickly. This is almost similar to an inflatable connection on a bike or pool toy inflator. Alternatively, a couple breaths will do.

With the opening option we can use our alternate air source and purge the air into the SMB. Our advice is not to shove the alternate in but gently purge below the opening as it could get trapped inside. Make sure all the loops are out of the way as well. Deflate your BCD a bit to make yourself slightly negatively buoyant. Purge just a bit of air so that you can “straighten” your SMB. This will allow you to inflate it properly and fully afterwards.

Another technique is using your exhaust/excess bubbles that you are breathing out. To do this we manoeuvre the opening near the exhaust of our primary regulator, tilt our head and breathe out. The air will fill in. It Is a little more complicated and takes some practise. This technique is often used by technical divers as it does not use any excess air from the cylinder.

 

 

Reels or WDS

Reels are essential tools for divers. They can be used to keep you in contact with surface support, guide you back to a known starting point, or to position you during search and retrieve operations. A common mistake is trying to use one type for all diving applications. This can lead to complications and potentially to danger. There is no point using a reel containing hundreds of metres of line to deploy a delayed surface marker buoy (DSMB) from a depth of five metres. Equally, trying to use a finger spool to reel out through a wreck or cave penetration might lead to entanglement. Reels come in a selection of lengths which are then attached to your surface marker buoy or tied off from a short line because it is crucial for you to have maximum safety whilst out on your diving adventures!

Probably the most common application for a reel used by recreational divers is for the deployment of a delayed surface marker buoy (DSMB). For this task, it must be relatively easy to release the line to freewheel and there must be little chance of it snagging.

 

Things to consider when selecting a deployment system?

We have to be cautious to never have the reel physically attached to ourselves while deployment takes place. Should any snagging or jam occur you want to be able to easily jettison the reel, line and buoy. There are a few reels that we can use to deploy DSMBs – winding knobs, finger and jump spools.

When selecting which reel to use, take your other gear into consideration. If you wear thick gloves while diving, a finger spool might not be a very effective design for you. Cold water divers frequently prefer reels that have winding knobs, which allow them to wind the spool more easily. Some reels offer tension control, which is typically controlled by a spring. Tension control keeps your line on your reel from free-spooling, or uncontrollably unwinding off of the spool. A strong argument for using a reel with tension is it allows you to control the rate at which a lift bag moves to the surface.

Finger spools are more ideal for shallow deployment of a DSMB, or as jump spools, to connect a diver from one already laid line in a cave system to another ensuring that at all times you are in contact with a line leading you back out of the cave. Spools require a certain amount of dexterity and caution is needed when wearing thick gloves. They also take time and practice in order to become proficient in their use.
Our personal favourite deployment system for recreational diving is the webbing deployment system.

 

What is a webbing deployment system (WDS)?

A webbing deployment system (WDS) is a compact and easy to use solution for deploying your surface marker for your safety stop at depth of 5.5m (15-18ft). The weight optimised WDS also ensures that your DSMB does not spill air on the way up or on the surface. Neatly secured by the elastic cord the WDS unfurls as the inflated surface marker ascends. The whole system is negatively buoyant thus eliminating the risk of entanglement with free floating cord. It is specifically only used for the task of deploying a DSMB. Here is a video which illustrates nicely the use of a webbing deployment system.

 

Top tips for using a diver SMB

Plan your dive

Although you may have a dive guide or instructor we can’t stress enough how important it is to be well prepared for a dive. Make sure they inform you or you find out about the dive site conditions and environment. Even having a laminated map on you can help navigate and also you can then appreciate the wildlife or scenery as well as enjoying the ride of a current or too.

 

On your dive check the surroundings

Before deploying, always look up for anything above. This includes sea life. Often you can see turtles above taking a breath of air before descending again and surely they wouldn’t appreciate an SMB hitting them. What is more, it could also tangle around them. Similarly any divers or boats above can cause the same problems.

Another common mistake is divers standing on coral to release the SMB. Please remember to be an eco conscious diver and protect the marine life. If you are unsure about your buoyancy skills, practice deploying an SMB in a lagoon first. Then practice in the blue. Eventually, you will be comfortable to deploy your SMB in any situation. Feel free to ask your instructor or dive guide to give you advice and help you out.

 

Attain your buoyancy first

When you are about to deploy it is key to have good buoyancy. You may find it easier to let a small amount of air out of your BCD before you deploy your DSMB to balance out the air which you’ll be putting into the bottom of the SMB. Remember that it’s also easier to deploy a diver SMB from slightly deeper (think 10-15m, rather than 5-8m) due to the differences in pressure being greater at shallower depth. These pressure gradients make it slightly more challenging to fine tune your buoyancy, and buoyancy is key to a great DSMB deployment. You need to remain neutrally buoyant to avoid getting tangled and to maintain a steady safe position.

 

The Air Expands

Don’t forget the first thing you learned about diving physics – air expands as it returns to the surface. Your depth will determine how much air you need to add to fill your SMB. Air from 10m will be twice the volume at the surface, therefore you need to fill your SMB halfway. From 20m you will only need to fill it one third.

 

Prepare the DSMB

Follow the same pattern each time of pulling out or unclipping your DSMB/SMB. Then unroll it and purge very little air to make it straight before inflating it completely. When you are slightly negatively buoyant, you can pull on the lint to make your SMB stand out straight at the surface.

 

Continue your education

Although you should briefly go through this in an entry level course we would always encourage you to practise and be trained appropriately. If you’re unsure of it, always check with an instructor or divemaster.
If it wasn’t thoroughly covered in your entry level course, DSMB deployment may be included on a drift dive on your Advanced Open Water Course and I can also offer the PADI DSMB speciality course to perfect your skills.

Happy Bubbles and don’t forget to use your 10% discount code for Surface Marker: diveintolife10