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How do I tie a good knot?
Attaching bolt snaps to dive gear like SPG hoses, regulators and backup lights make them easier to stow.
Now a common question I get is: So how should I tie a long lasting knot?
We’ve addressed the different types of knots in a previous article, so read this if you would like to find out more about attachment options.
In this article, I’m going to show you how to get a good solid knot tied, so that it lasts (almost) as long as your gear.
A lot of other articles and videos also show how to tie a knot, but I’d like to highlight some of the more important things that I look out for to make sure the knot stays tied over a long period of time.
At the end of the article, I’ll also show the common errors that might cause a knot to fail.
Line choice
Traditionally, most people would use the same line found on their spools to tie their knots.
I’m not a great fan of this, for 2 reasons.
Firstly, it shortens your spool, resulting in an unknown length of line left on the spool.
This is a problem especially if you have a lot of things to tie. I would never recommend going diving without knowing the length of line you have on your spool.
Secondly, and more importantly, I don’t find the braiding on that line appropriate. It’s much too heavy.
A tighter and thinner braid on the line doesn’t stretch as much when wet, creating a more secure knot that doesn’t slip.
Image of a thinly braided line on the left and a heavy braided line on the right
Loop around the connection point and bolt eye
I normally go for 3 or 4 loops around the connection point and the eye of the bolt snap.
For long hoses and SPG hoses, I tend to do 4, but for heavier or other more dynamic knots, I would use more, sometimes up to the width of the bolt snap eye.
Looping the line through the eye of the bolt snap
Cross over and pull tight under the bolt snap
After getting the loops nice, neat and tight, I would bring both ends of the line to the same side of the bolt snap.
Getting the line to the same side of the bolt snap
Then cross both ends of the line and pull them tight, pulling them under the eye of the bolt snap.
Crossing the line and pulling it tight
Pulling the line under the eye of the bolt snap
Ensure that the line is tight around the original loops, making sure that the outer loop is cinching the original loops tight together.
Right over left, left over right
A nice solid knot requires a good tie, and the best one for this situation is the square knot.
Right over left and left over right, that’s a simple phrase I remember to get this correct.
It’s a good knot because the lines tighten on themselves, and it forms a nice flat knot that doesn’t stick out and get abraded.
Tying a square knot
The final square knot
Cut and burn one end at a time
Once the knot is nice and tight, it’s time to seal the ends by cutting and burning off the tips of the nylon line.
The trick here is to cut and burn only one side at a time.
Cut the line as close to the knot as you can, about 1 or 2mm away from the knot.
Only cut one end of the line first, do not cut both sides!
Use a lighter and place it perpendicular to the line, using the heat from the blue part of the flame to melt the line onto the knot itself.
Use a lighter to burn the tip of the line and melt them onto the knot
The melted line on the knot
It’s important to make sure that the excess line is melted into the side of the knot.
This is critical so that the line doesn’t pull out when you cut the other side of the line.
The final knot in all its melted glory
Make it last forever!
I’ve tied knots that have lasted 5 or 6 years with this method, so by following this guide, I’m sure you’ll be able to get a good knot going. Good luck!
Common errors to look out for
Wrong knot
It’s very common to tie a granny knot by repeating the same half knot in the second half of the square knot.
This is not a good knot and tends to slip.
It also tends to stick out, making it prone to abrasion.
An old timer granny knot
Not doing one side at a time
The problem with this is that pulling on one side of the knot will cause the other end to slip out if you’re not careful.
In the least, this will cause the knot to slip and open up a little bit, making it looser.
Cutting both ends of the line before burning them results in a loose knot
Not burning the line into the knot
Burning the tips of the line away from the knot allows the line to slip back into the knot, loosening the knot over time.
Burning the tip of the line away from the knot results in pull back and loosening of the knot
Choosing the best surface marker buoy (SMB) for your dive
Surface marker buoys are handy for a number of occasions, whether it’s to signal your position to your boat at the end of your dive or during emergency ascents.
When you need immediate help or when someone in your dive group needs to get to the surface quickly, you’d want to be able to deploy the bag without it causing other problems or making matters worse. That’s why choosing a suitable SMB for your dive is so important.
There are three main factors a diver should consider when choosing a surface marker buoy: its size, method of inflation and the length of its line.
- What size do you need?
To be useful, the marker must be visible on the water’s surface, so it should be as large as you can manage. My emphasis is on what you can manage. You could have the largest marker on the planet, but if you can’t inflate it properly, it would simply be a limp piece of plastic floating on the surface. That certainly won’t be noticeable from a distance — unless the boat crew is consulting Google Earth.
Therefore, the size of the SMB you choose should be the largest that you can reliably fill from depth. Personally I prefer a smaller, thinner bag that will stand upright when filled with a relatively small volume of gas. I use the Halcyon 1m SMB on all my dives. This bag will fill up completely with only a single regular breath at a depth of about 10m. If you are at a shallower depth, then you’d need to blow in a larger breath of air, but it’s definitely still possible to fill up the bag quickly and send it on its way without much stress.
Now you might be wondering, what if you’re diving at sites with large waves and surge? Wouldn’t a larger (more visible) surface marker be better? In response I would ask: Is the dive worth putting yourself in such a situation? If the answer is yes, then make sure you are prepared for it with a larger surface marker.
Remember that a larger bag must be filled with a greater volume of gas in order to stand upright on the water’s surface. This means you’d need to either blow more gas into it (by exhaling or purging from the regulator) or release the bag when you are at a greater depth to allow for more gas expansion. The latter would be a good option, but the downside would be the much longer line that you would have to reel in as you ascend.
I would normally only inflate these larger surface markers once arriving on the surface and the boat is further away. The bigger marker will be easier to spot from a distance, but will also be harder to manage while underwater.
- Which method of inflation should you use?
Open circuit SMBs are some of the commonest in the market. To inflate an open circuit SMB, a diver typically purges air from his alternate air source into the bag. However, I do not recommend this method of inflation for a number of reasons.
The large amount of air purged from the alternate air source would likely cause a fairly significant and sudden buoyancy change. In an emergency or stressful situation, a sudden change in buoyancy could easily spiral out of control.
The force generated by the large volume of gas also means that the SMB will take off towards the surface really quickly. If the diver does not manage the line well, the line could get tangled with the BCD or tank, and drag you up to the surface. Nobody wants to be a human SMB!
I would always opt for the oral inflation method, because it is quicker and safer. The amount of gas that you exhale would not cause a significant buoyancy change (unless you inhale an extra-large breath of air right before). This makes the buoyancy change much more manageable. You wouldn’t need to find your alternate air source, too.
If like me, you prefer the oral inflation method, what’s left is to choose an SMB that works best with it. It’s possible to orally inflate an open circuit SMB, but due to the line being attached near where the open end of the SMB, there is a higher risk that your regulator might get caught in the SMB line or the SMB itself. Definitely not my first choice.
There are many SMBs on the market that are designed for easy and effective oral inflation. They normally have an oral inflator with a one-way valve. This, in my view, is the best one to use because it guarantees that the gas goes directly into the SMB. It’s also really easy to use. The Halcyon SMB I use does not have a locking mechanism, so you won’t need to fiddle with extra bits to inflate the bag.
- How long should the line be?
Some SMBs come with a 5m line, which means you can deploy the SMB only at the 5m safety stop. Obviously this is limiting, as you might run into other situations where you need to deploy the SMB at a greater depth. My advice: Always get a longer line that’s wound around a spool.
SMBs do not always take a straight path up towards the water’s surface, and might ascend at an angle when there is a current. As such, always make sure your SMB’s line is longer than your deepest planned depth. This means that if you are doing a 30m dive, then a 30m spool is not going to be sufficient. A 45m spool would be a better choice. I would use a 30m spool for dives to depths shallower than 25m.
In summary
My recommendation is to get a small thin SMB that you can reliably fill via oral inflation, and use a spool with an appropriate amount of line. Also, remember to practise deploying your SMB after buying one! A seasoned diver can easily get a bag deployed in less than 15 seconds, so keep practising until it becomes second nature!
Should we use an inflated surface marker buoy throughout a dive?
Most divers recognise that the surface marker buoy, or SMB for short, is an essential piece of dive equipment. However, not everyone agrees on the point of whether to use it throughout a dive.
Some divers inflate a highly visible surface marker buoy before descending, and the buoy follows the group throughout the dive. You might see this happening at shallow bays or dive sites where boat traffic is high. It seems like a good idea, since the marker lets boats know that there are divers below, but is it really?
Now let’s look at what could go wrong in such a scenario.
Firstly, having to tow something along (in this case, an inflated marker on the surface connected to a line held by an underwater diver or attached to his BCD) is not only tiring but also hard to manage. The diver holding on to the reel or spool has the responsibility of releasing and taking in the line according to changes in depth. If your divemaster had to manage this, do you think he would have the capacity to also lead the dive and keep track of all the divers?
What’s more, divers might also swim into the line and get entangled, making the dive even more difficult.
Secondly, there are often winds or surface currents at many dive sites. This force pushing on the surface marker buoy may oppose the underwater current or the direction taken by the divers. Fighting the drag and getting the SMB to follow you during the dive would be a challenge.
Lastly, even though the surface marker buoy serves to warn boats, people do still make mistakes. In my years of diving, I’ve seen more than one boat drive right over an SMB. If the SMB line was attached to a BCD, what would happen if the line got caught in a propeller? I shudder to think of the possibilities.
In my view, surface markers are useful only when divers are surfacing or in situations where the conditions are such that the boat must follow the divers throughout the dive (for example, strong current, heavy surge and open ocean diving). The method of diving with an inflated SMB throughout a dive would not be a first choice for me, when planning dives in relatively good conditions.
What’s more important is ensuring the diver has good skills, especially buoyancy in this case. If a diver had excellent buoyancy and awareness, he would be aware of the loud noise generated by an approaching boat, and stay close to the bottom.
Finally, let’s consider two divers with excellent buoyancy skills: One has an inflated SMB attached to him and the other has none. A boat passes overhead. The diver with the line, through no fault of his own, might very well get pulled up into the boat’s propeller. The diver without the line, who upon hearing an oncoming boat, stays close to the reef or bottom and faces no such risk.