Descent/Safety Checks (S-drills, Bubble & Computer Check)

Descent checks are a great practice to get into doing on every dive. The descent check (aka s-drill, bubble, safety check) consists of 4 underwater checks. 3 before starting your dive and then a 4th if diving beyond 30m. The order of the checks should be discussed in the dive briefing along with the relevant signals, and what the course of action will be if there is a problem.

The start of the checks are normally indicated by the diver drawing a large S in front of them towards their buddy.

Check 1 – Bubble Check
Common Signal – I, Look, You, Bubbles
Your buddy will then either duck their head or twist slightly giving you full view of their 1st stage and hoses for a couple of seconds. You are then looking for bubbles coming from any part of his setup. Either your response would be ‘OK’ or ‘Something Wrong’. You then reverse the check with your buddy doing the check on you.

Check 2 – Alternative Air Source/Reg/Octopus semi deployment or full deployment.
Common Signal – I, You, Point at Reg, Switch
A full deployment is where you will release your alternate Reg to your buddy and allow them to take a couple of breaths before replacing the Reg. This is normally good to do with a new buddy or if you are diving with different kit configurations such as a long hose primary donation. For a semi deployment you demonstrate your alternative Reg can be deployed easily and will be free of any tangles and then restow. This check is not designed to replace your buddy checks, but to give you and your buddy chance to experience the donation underwater. As per the problem with tangles, you will see many divers do their buddy checks, then before going in the water, they add all their accessories.

Check 3 – Gauges Check
Common Signal – Look, Point to Wrist/Gauges
You are checking to make sure your computer is on and working as it should be as well as checking other gauges such as your gas. You should have agreed on a depth, so this gives you a chance to check your depth gauge is reading the correct depth. If they are working it is a simple ‘OK’ to your buddy if not then ‘Something Wrong’.

The checks are normally completed at a depth of around 5 meters. 5m is a good safe depth as it’s not deep and gives you a chance to sort any issues before descending. Now there are many dives and circumstances where it will not be possible to complete the checks at 5m. If this is the case the checks should be done as soon as possible. This could mean they are done at the bottom of the shot.

Check 4 – Narc Check
Common Signals – Flicking/Tapping the Cheek/Head
These checks should start between 25-30m (Depth Narcosis starts to kick in). If you are going beyond this depth, it’s good practice to do the check every additional 5 meters. Once you have reached you maximum depth, it is normally good practice to do a check after a couple of minutes. This is because they say Narcosis maxes out after this time (so if you stay at that depth you will be as Narc’d as you would be during the dive. As per the checks, there are a number of different ones you can do. 2 Common ones I see and use are;
Total 5 – This is where you put up x number of fingers, then your buddy puts up y number and the total of the 2 should equal 5. So if I put up 3 they put up 2.
Plus 1 – In this test works similar to ‘Total 5’ but your buddy instead puts up the next number in the sequence. So I put up 3, they put up 4.
It is good for your buddy to check back, and to use a different check if possible. As a buddy you are looking for 1) The correct test being carried out, 2) correct answer being given, 3) answer being given fairly quickly.
If anyone does any other checks, please share them.

As always I hope you have enjoyed the read.

G-SAV

 

Have Enough Gas? Is That 12L Really Suitable For 30m Divers?

I am going to assume, everyone reading this understands SAC and RMV rates, if not please check out my blog:
https://grahamsavill.wordpress.com/gas-management-and-planning/

Here we are going to look at some calculations to work out how much actual ‘Safe Time’ you have at different depths with various size cylinders, as well as looking at how far that 3L pony may get you. As per the blog above, I now apologise, as I am a UK diver these calculations are all using Litres, Meters and Bar.

First let me clarify ‘Safe Time’, where in an emergency you can ascend at a rate of 10 meters per minute, stop and hold a 3 minute safety stop at 5m, and surfacing with 50 bar. Anything else I would class as unsafe which has a higher chance of ending with an injury and maybe lead to a trip to the chamber (No one wants that).

For these calculations I have used a few assumptions in addition to the safe criteria above;
SAC of 20 (Average for most recreational divers, newly qualified can be in the 25 to 30 range giving even less time).
1 minute at depth to address the issue. This might sound like a long time, but if you have an out of gas situation on a wreck with a strong tide, you may need to also launch a DSMBs.
SAC multiplied by 3 to take into account the way the body reacts to a stressful situation. (In some divers it may double, but studies have shown it can increase to 4 times as much especially with inexperienced divers).

So below I have put a table together with 4 categories and each category as 3 Cylinder sizes 10, 12 & 15 litres. On the left going down we have the various depths. The figures in the table show maximum bottom. The green is a Safe Accent from the bottom buddy breathing, completing a safety stop and having a 50 bar reserve. Orange is if you ascended and skipped the stop (Not to much of an issue but not ideal). Light red you ascended completed a safety stop, but would have no air left (This is getting dangerous, slightly longer at the bottom, at stop or not come up as quick you would run out of air before you reached the surface). Red is if you skip the stop and surface with no reserve. The worrying thing about this, is how many divers have you seen do a 20 to 30min dive to 30m on a single 12 (There is a popular wreck near me, where this happens all the time). Looking at the chart below after 17 minutes they would not be able to perform a safe ascent while buddy breathing and most likely run out of air before reaching the surface.

As from the table above, this is why it’s extremely good practice that if you are diving below 20m having an alternative air supply can greatly improve the safety of the dive. I do know some operations hang a spare cylinder from the boat, however this is only any good if you can make it back to the shot line. This could be an issue if you were far away from it, or like the wreck I mention above that has a huge tide, will take you away from it.

Now I do see a number of divers who carry a 3 litre pony, which is a vast improvement on the above, but again a lot of these divers are unaware of their limitations. Below is a table broken down similar to the one above but shows if you will surface with air left in your tank or if you would be short. These are similar to the calculations above, however only calculated for 1 diver breathing off it. For an example if you tried to surface from 30m and wanted to perform a safety stop you would be 360 litres short. However even if you skipped the safety stop, you would still be 90 litres short.

Of course if you are with a buddy, the pony would get you out of a tricky situation and easily get you to a depth where you could then switch to your buddy’s alternative air source/octopus and safely ascend. This is one of the reasons, when venturing below 25 and especially 30m you should really be considering a twin configuration setup such as backmount or sidemount. What I hope people take away from this is this size pony is not really big enough to give you that a safety net you may think it does below 25m.

Again thank you for reading the post and as always, I do love a good discussion about my views.

G-SAV

Gas Management and Planning

There are few basic gas management rules that most divers follow, the most common is rule of thirds, which is a third used for outward part of the dive, a third used for return journey then a third in reserve for emergencies. There are also a couple of others normally reserved for overhead environments such as rule of forths and rule of sixths. Having turn pressures is an excellent idea and practice in dive planning and dive management, however how long does that third of gas actually give you?

Enter SAC (Surface Air Consumption) or RMW (Respiratory Minute Volume), which just relate to how much air you use at the surface allowing you to plan your dive in a little/a lot more detail. I have always used the SAC terminology and being a UK diver, I will be be doing the calculations in Bar, Litres and Meters. So in this post I am going to discuss
1) How you can work out your various SAC rates
2) How you can used these in dive planning

There is a simple calculation to work out your SAC Rate; Amount of gas used divided by time then divided by ambient pressure.

So lets take lets take an example dive using a 12l cylinder, Start Pressure 210, End Pressure 105, Max Depth 20, Avg Depth 15, Dive Time 25.
Amount of gas used: 210-105=105. 105×12(cylinder size) = 1,260ltrs used.
Time: 25
Ambient Pressure, we will use average depth as we want to find the average SAC for the dive: 15 divided by ten, then add 1. So 15/10=1.5, 1.5+1=2.5
So our average SAC for this dive would be 1260/25 = 50.4, 50.4/2.5 = 20.16

If you have the information record in your dive logs, you can always work back through them working out your average SAC rate for each dive. This will give you a good starting point to understand your SAC rate. You will notice your SAC could change dramatically from one dive to the next, this could be on how hard you were working on the dive, ie drift vs swimming into a current or if you were in warm water or cold.

For those not the greatest at Maths there are plenty of free online calculators available. However if you manage to learn the formula its very easy to do rough calculations on the fly, which I will cover later.

So far we have looked at Average Dive SAC rates, but once you have got your head round that, there are actually 3 rates you could do with knowing. First is your static SAC rate, this is your SAC when basically hovering not swimming such as holding a safety stop. This one is fairly easy to measure, hold a stop for 5mins, note the depth, start and end pressures then do the maths above. 2nd Normal SAC, this is the rate for normal swimming, the trick is to choose a depth, and as per above make a note of the pressures, swim for about 5mins one way and then back the same way for 5 minutes (this takes into account any current). 3rd is your working SAC rate, ideally you want to do this in the 5m depth range for safety, find something you can hold on to, take a note of pressures, and kick hard and quick for about 3mins.

Now we know our various SAC rates we can plan out our dive in as much detail as we like. It might be as simple as working out how long you have for the whole dive, to planning you gas usage at varying stages of your dive ie Decent gas used, leg 1, 2, 3 etc of the dive, Ascent gas, Safety stop gas. If you go into this much detail you can closely monitor your dive against plan to see if you are on track. You can also use it to work out how much gas you need in an emergency. I have written a 2nd post about this here where I highlight the risk of using single cylinders on dives below 20m
https://grahamsavill.wordpress.com/2017/07/26/have-enough-gas-is-that-12l-really-suitable-for-30m-divers/

Last of is calculations on the fly, for example if you have the following Static SAC 11, Normal 14, Working 20. It can make calculations extremely easy to allow you to work out how much gas time you have left. So using the rates above 18 which is between normal and working rates allows a margin of increased workload, but it also fits nicely into a 12l tank as 1.5bar. So if you are at 10m, its 3 bar (mulitplied by ambient pressure x2) a minute, at 30m its 6bar (multiplied by 4) this makes calculating remaining air time extremely easy.

Maths can be a rather dull subject to some, but I hope this gives you an idea on how you can calculate your gas usage and how to use that for better dive planning.

As always thank you for reading.

G-SAV

Are Hose Protectors Necessary or a Risk?

So in this short blog, I wanted to share my thoughts and opinions around hose protectors. I am going to start with why we have these, then go on to how you can cope without them and finishing off with the issues I see with using them. Now with all my posts my views and logic is to make things as simple and as safe as possible. First off are the hose end protectors, which you will find on nearly any new Regulator set you buy. The weakest points of the hose are the joins at either end where the rubber/plastic meets the metal fixing. In come the hose protectors, as these act as a barrier and provide additional support, stopping the hose from being kinked at this weak spot. Next up is the wrap around hose protectors, which act as a barrier from the Sun and being damaged by abrasion against other objects/environment.

Now from that you may be thinking they are great and how could we live without them! The answer is simple ‘Look After Your Kit’ i.e. Don’t bend the hoses at the joins (If this is done by you kit configuration, then adjust the configuration), pack them securely when travelling, keep them out of the sun, don’t drag the hoses over rough surfaces.

So now lets look as some of the drawbacks I see see with these protectors.
1) Out of sight out of mind. As seen in the photo above the protectors actually hide the weakest part of the hose, and therefore could be hiding issues or potential problems.
2) Petri-dish. These provide the perfect environment for salt, sand and grit to build up, which can increase corrosion and servery shorten the lifespan of the hose.
3) Additional Pressure. To stop/slow issue 2 requires proper cleaning and regular inspection. This means pulling the protector back down the hose out of the way. The problem is every  time you do this you are adding pressure to the join as well as causing friction damage to the hose.
4) Regulator/Gauge Breakages. Some of these protectors can be extremely tight, so when removing the protector at the 2nd Stage or Gauge end you need to hold that piece of equipment. This in turn is adding additional pressure to the piece and increasing the chance of being damaged.
5) Fix the leak. The protector could also act as plug for any leaks, by reducing the air escaping, which could mean the issue is missed during a bubble/5m check. However this would be picked up in the additional Regulator checks I suggested in my previous post;
https://grahamsavill.wordpress.com/regulator-pre-dive-checks/
6) Completely pointless. These are the protectors that are too loose that slide down the hose by themselves, offering no support or protection what so ever. (Seen plenty of these in my time)
7) Pollution. I am now talking about the wrap round protectors, which do deteriorate over time and start breaking up. The broken plastic/rubber pieces often come off and are left by the diver rather then being disposed of properly.

As always I hope you found this useful or interesting, and would love to hear others thoughts on this.

G-SAV

 

My GOOD Bag (Get Out Of Dodge)

So as I have been putting together this blog, there have been some interesting debates/posts happening on various forums about what accessories Divers carry and why. Sometimes the hardest question is not ‘what to take’, it is ‘where to store it’. Normally for most recreational the answer is shoulder/chest D-rings or in BCD Pockets. Here in the UK many divers wear dry suits, which sometimes have the added benefit of thigh pockets. In this post I am going to cover off what I carry in my GOOD bag. I am starting to put together a blog on storage options. As per previous posts, these are my views and opinions and as always keen to understand what other people carry and why.

Clips: I carry a spare double ender (technically I have few available as the pouch connects to my harness by 2 on the outside, I also have one each for back up mask and dsmb). These are great for carry equipment such as Mask and Fins while moving about on land. I also carry a quick release, this allows me to clip any hoses off if their own clip fails. Please see my previous blog here about clips:
https://grahamsavill.wordpress.com/choosing-the-right-clips-could-save-your-life

Spare Mask: Out of all the things, a diver should carry for back up, this should be top of the list and carried by all. Most diving incidents have multiple solutions and work arounds if the diver works the problem. However the loss of the ability to see because of a broken mask only has one solution. It is also one of those problems that will have multiple knock on effects and could lead to further issues and problems relatively easily. Reduced ability to communicate, monitoring of gauges, maintaining accent rates or stops, managing equipment and so on. I personally have never had a mask fail, but have provided my spare to various buddys due to their own masks failing. I was teaching once when an experienced diver pointed out they never carried a spare as never had a problem, the following week their mask broke in the pool. One thing to remember is keep it clean/defogged! One time I donated mine to a buddy for them to put it on and for it to instantly fog up.

Dive VHF/Personal Location Beacon: These are great and ensure you have a greater chance of being rescued if lost at sea. I am sure most readers here would have read articles about lost divers, and they happen all over the world. It’s also not just boats forgetting people, its just as likely to be caught in a current or tide, sea state to change, a fog to come in or the boat breaking down. I personally have the Nautilus Lifeline which is a Marine VHF Radio GPS, with a distress beacon built in, which will send out your coordinates. Now there are laws in some of countries around operating VHF radios, however everywhere allows the use of VHF in an emergency. So if you want to use it to get your drinks order in while waiting to be picked up you might want to look at doing a course. I have so far used this once in sort of anger, my DSMB got tangled and had to let it go. I had left my back up on the boat as it was only a 10m dive about 1000m offshore. Anyway when we surfaced the boat was exactly where I thought it was going to be, sat near my DSMB waiting for us to surface. Quick radio call to tell my Dad to look round was all it took. I also have this on shore dives, knowing I could surface, radio the coast guard to arrange an ambulance as I make my way to shore/safety.

Wet Notes: These are great for diving and communicating with other divers. I have added some additions to mine. Inside the front I have my emergency details, Name, DOB, Contacts, Blood Types, Meds, Allergies. I also have instructions on how to use my Radio as I could be unconscious and it will be down to my buddy. I cover this off in the Dive brief / buddy checks.

 In the back I store some laminated deco tables, fish ID, and a plastic signalling mirror.

On the back I made up a small grid of words which I find useful with less experienced divers who only know a few hand signals. I have also tried to keep it fun such as being able to say ‘this is crap’ or a special one ‘Diiiiiiick’ which I put in their for one of my buddy’s who likes to do less then intelligent things, such as sticking his hands in holes looking for treasure….

Cable Ties: Similar to duct tape, there are all sorts of things that can be repaired / temporary fixed with cable ties; broken clips, fin straps, mask straps, BCD clips, the list goes on.

Spare Mouth Piece: Hopefully any mouth piece issues would have been picked up in the Regulator checks. However splits and tears can easily happen underwater. I have known divers to put up with the issue rather then call the dive, which is adding a huge risk in my opinion. If they suddenly have to deal with an emergency and their breathing rate picks up, there is a higher chance of breathing in water. The spare takes no space and can swapped underwater in a couple of minutes.
https://grahamsavill.wordpress.com/regulator-pre-dive-checks/) 

Whistle: While having the VHF Radio is great, I would not put all my trust into an electronic device, so having a back up signalling device is a must in my view. There might be sites, such as a quarry or beach where a whistle we easily get the attention you need to summon assistance.

Back Up Spool and Mini DSMB: If you speak to divers, it seems reels and DSMBs are the probably most common lost items on a dive. Just recently on a boat dive a buddy pair lost both their primary DSMBs due to the current and them becoming entangled on fishing nets. You will notice, I have the amount of line written on the side of my reels, as when you own a few, its difficult to remember how much exactly is on each one. For example this one is 27m, so would be no good sending up from the bottom from 30m.

Back Up Torch: This one pretty much self explanatory, as with DSMBs being the most common lost item, torches seem to be the most common equipment to fail, with bulbs going, batteries dying, flooding. In addition its a great signalling device while on the surface on dusk and night dives. I also find having one useful when diving with a new buddy especially when less experience, as you tend to find they like to follow, so normally slip back behind up. In giving them a torch to use, it helps you to track where they are by keeping an eye on the beam.

Multi-tool: This is Best Divers multi tool, another awesome little accessory, I only have the cross version which has Hex Keys on the end, and fits most Regulators (Can be tricky getting to some hoses). This is ideal for dealing with those loose hoses or tightening blanking plugs.

All this goes into my sidemount pouch and clips onto the bottom of my harness and comes with me on nearly every dive (backmount and sidemount). If you are wondering about cutting tools, please check out my previous blog:
https://grahamsavill.wordpress.com/cutting-tools-choosing-the-right-one/

I hope you have enjoyed reading this and have decided to nick some ideas for yourself. Until my next post, happy safe diving…

G-SAV

Choosing The Right Clips Could Save Your Life

First off I will hold my hands up to say I have used everyone of these in my diving history, but after being informed of the dangers of some of them and experiencing some of the issues first hand, I now only use bolt snaps & double enders. Below I will cover off some of the clips I see regularly on divers and why a couple of them have nicknames like suicide clips.

Before we get onto the clips there is one rule worth following ‘No Metal to Metal’ connections – everything should be able to be cut away. This also goes for to plastic to plastic. This is a safety issue that if an object you have attached to you becomes entangled or stuck and you cant remove the clip (damaged or blocked), it can be cut away without impacting your BCD/Harness. For example the picture below shows a common reel that is connected to its snap bolt via a metal loop. If this is then clipped to the D-ring there is no way of cutting it free without impacting your buoyancy device. In this instance it would be better to change the metal loop with some thin cord. To remove this issue in this example, you could simply change the metal loop to a thin rope loop or tie the snap bolt to it. The problem comes from accessories being a hazard either becoming entangled or trapped. This is why the item itself (not necessary the clip) needs to able to be cut away.

Each of these clips do come in different variations, and it is the mechanisms of opening and closing the clips that cause the problems. As with my other posts, I am not telling you which ones to use, just giving my own views and experience. In my mind, I am always looking at how to be a safer diver and strongly believe the small changes add up. I am working on a post where I will go into the benefits of changes and how everyone could be Safer Better Divers. Anyhow lets get back to the topic of clips.

Carabiner (Aka A Suicide Clip): In diving you need to be able to be un-clipped quickly and cleanly as any problems or snags will slow/stop the speed of problem resolution. The greatest issue with these types of clips is the Gate opens inwards and is the biggest draw back to using this clip in diving.
1) As from the picture above you can clearly see, any item that needs to be un-clipped needs to sit in area A which is in the top half of the clip. If it sits anywhere else it will be impossible to get off. To get round this the item needs to be moved to the top of the clip, which brings the first possible problem.,pressure on the item may stop it from reaching area A.
2) If an item is big enough, such as a large piece of rope, it can easily be forced into the jaws, this large item can then act as a barrier stopping the Gate from being opened fully. I have seen this happen a lot in Sailing, especially with the Notch acting like a fish hook adding another issue to overcome.
3) Building on the comments above, if a number of items can enter the clip accidentally, the issue will be compounded as you will need to  clear the various attachments.

Butterfly Clips (Aka A Suicide Clip): First off these are a big step in the right direction compared to the Carabiner type clips. The jaws open straight up and down, meaning un-clipping is extremely easy, as you open the jaws and everything comes out. So you might now be asking ‘what is the problem then?’. These clips bring a completely new problem to the mix, the ease of accidentally clipping themselves to objects (mainly line and rope). The V entry of the jaws makes this it extremely easy for an object to make its way into the jaws without the diver knowing.

Snap bolts: Do not come with the problems and risks associated with the others and this is why they are a chosen favourite with technical divers. They are not the easiest to use with thick gloves when first starting out, but there are a couple of techniques you can use to make them easier. The photo above shows the one I currently use. Depending on size of clip and the gloves I may be wearing either my pinky or ring finger fits into the loop to take the weight and control the object. My middle finger applies pressure against my thumb to allow the opening of the jaws. My index finger then acts as a guide to find the attachment point ie D-Ring, then help the clip onto it.

Double enders: These work similar to snap bolts but have the benefit of being able to completely disconnect from either end, however they are longer and neither end is fully secured leading to an increase chance of the item disconnecting and being lost.

Plastic Clips: These are extremely easy to fasten, as its just a push and click. However disconnecting can be fiddly with gloves and if pulled at a slight angle while releasing one side can cause them to jam. Forcing them normally causes a breakage, things that break easily underwater are not the greatest inventions. They normally become a pointless addition as you will see divers use one of the clips above to secure one end of the clip to their BCD/Harness. Keep it simple.

Lanyards: Now having one to that lovely new camera is understandable, and although brings entanglement issues (number of times I have seen divers reconnect the join with another piece of equipment in the loop to then have to fiddle with it later on) as a single one can be manageable. A word of advice you may find the a suicide clip one end – change it. I would strongly recommend get to the point where you use a single bolt snap, un-clip when needed, then re-stow when finished. Idea is to keep your kit tidy. The lanyard should be located where you can fully see it and as far away from other accessories as possible as not to interfere. More then 1 will more then likely cause issues and negatively impact an emergency.

G-SAV

 

Save A Dive

Nothing upsets divers more then a dive called due to avoidable faulty equipment. Equipment gremlins come part and parcel with diving, the little buggers are very effective at throwing a spanner in the works.

In this post I wanted the discuss our saviour in these events, the loyal and trusted ‘Save a Dive’ kit. Now as in most things in life the size and comprehensiveness of these range from a an old rusty spanner, to tool boxes with so much stuff you could build any piece of equipment from Scratch.

In this blog I am going to share mine and its contents with you. Now tools are useless on their own without the knowledge to go with them. There are a number of courses out their around equipment care and servicing, at the bottom you have the ones basically re teach you how to wash your kit to the ones that will teach how to fully service a regulator.

Case: Ideally you want something to store every thing in altogether so nothing gets left behind. To make things easy at the dive site, it should also allow easy organisation of its contents. I managed to find this slightly larger then A4 size tool folder online.

Instructions: These can be a big help, when trying to resolve a problem. Exploded parts diagrams give you the ability to understand where the possible issue and how big or complex the job is going to be. I have considered doing laminates of my instructions but have yet to get round to it. To cut down on size only take copies of the parts you need.

Service Kits: In the UK these are a little harder to come by as they are generally not sold to the public, however they can be found online. Even if you don’t service your own kit (I will do another blog post on that another day) it is still a wise idea to carry a couple of sets of spares. You will find some dive shops / centres may be qualified to service your kit, but might not have any in stock meaning a 3 or 4 day turn around, ruining your dive holiday/trip. (Keep them in original packaging so the centre knows it is the right ones otherwise they may refuse to use the parts, some may refuse anyway). Also consider service kits for any dry suit valves and BCDs/Wings you have.

O-rings, Inflator hose valves and Pressure gauge spindles: Don’t rely on new O-rings being perfect The number of air leaks I have seen due to either a faulty / damaged newly fitted O-rings. Ensure you have a reasonable supply and learn how to change the simple ones.

Blanking Plugs and adaptors: Now I have fairly standardised kit so apart from a spare elbow for my 2nd stage, but carry these to get a buddy or friend out of dodge. There is also a chance I might have a hose go and the only alternative is an odd size.

Tools: Selection of common tools, wrenches, socket set, pliers, O-rings picks. With some special tools dropped in for good measure; Inflation Valve Tool and Inline Adjustment.

Attached is more comprehensive list that I use as a handout for equipment care courses I run. Equipement Care Handout

There a few other additions that people may consider including in a ‘Save A Dive Kit’
Spare Batteries for Torches and Computers
Straps for Mask and Fins
Hoses (I normally throw in one of my other  regulator set configurations that I could butcher if needed.

With my own Save A Dive kit and knowledge, I can confidently repair 90 to 95 percent of any equipment failures I will have with any of my own kit.

I hope you have found this useful, and as always would love to hear what over divers carry.

G-SAV

Cutting Tools – Choosing the right one

In this post I would like to share my thoughts and opinions on the various cutting tools available and where is best to store these during a dive. The photo is my selection which I am going to talk through, and will talk about each one in general terms. In my view it is always wise to carry at least 2 different types of cutting tools. I normally carry the first 3 on every dive. No 4 only comes with me if I specifically need it for the dive objective,

1) Medical Shears: If I could only take one cutting tool, shears would be my choice every time. They can be used one handed (most of the others require you to hold the object with the other hand). Can cut most stuff from fishing line, to webbing, to thin rope. Due to the nature of them being scissors cutting can be extremely accurate. Its difficult to hurt yourself with them or a buddy unless you trap your fingers. Due to the blunt end they are also great at cutting people out of BCDs/Harness, Dry and Wet suits. They are extremely cheap at a couple of quid so no tears if lost or broken. Down side to them is the pivot pin, which does tend to rust over a period of time. Which is not an issue as mentioned above cheap to replace. If the pin does break on you, you can still half the shears as a sort of knife.
You can get Hybrid versions which is mainly a knife, which would seem like a good idea, however they only add a couple of the benefits above, but come with all the negatives of a large knife. All the versions I have seen are spring loaded, meaning that the jaws will open if the catch is knocked off which just looks like an accident waiting to happen.
Storage: Waist Strap, Shoulder Strap (Keep clear of D-Rings), Outside of Pocket / Pouch, Inside pocket (If I am carrying them in a pocket – You could keep them outside a sheaf by either putting some masking tape round them to keep them close – very easy to break or wrap bungee around the other end to act as a closing spring). Ideally they should be placed within easy reach (Torso/Arms area). I keep mine on the outside of my bum pouch (will share more about that in another discussion). Whatever you do don’t attach it to a D-Ring by a clip as it will add clutter to the ring and will flap about under water.

Safety Cutter: These things are great with some being more compact then others and can be extremely sharp. Similar to the shears these can be used one handed, however you may need to use the other hand to put tension on the object you are cutting. They are great at cutting fishing line, webbing and thin cord (anything that will fit in the gap). These can also cut people out of suits quicker than any other the tools, hook it in at the neck and just pull it all the way down the body.  Unless you have the smallest of fingers and then try to wedge them into the gap you are not going to cause any harm with this cutting tool. Only downside to them is due to the opening you are restricted on the size of item you want to cut.
Storage: Anywhere there is webbing, and it is very common now to see divers add these to their dive computer straps (just be warned they a stiff to pull out, so will put additional strain on the strap a solution to this to have a separate bungee for it). Again should be easy to reach. Mine I permanently fixed to the loop on my crotch strap as the difference in location is negligible, however being permanently fixed I can’t ever forget it. As per shears try to resist just clipping them to a d-ring to float about.

Small Blunt Knife: Small I mean 2 or 3 inches total. I use this as less of a cutting tool more of a tool for brute force jobs such as cutting thick rope, bending things open and that sort of thing. It does very much take 2 hands to use, as you will need to create tension on the object with the other hand, if not will not cut. You can cut up to medium size rope but it all requires a sawing action to cut. If sharp it can be easy to cut yourself or your buddy, but the blunt end reduces the chance of stabbing.  You will be able to use it cut some one out of a suit but you will most likely cut them in the process (especially if trying to do it quickly) Storage: Again on webbing, shoulder, on BCD pockets etc. Mine is attached to by BCD inflation hose and stays there permanently. Easy to reach and use, but be careful when replacing it not to puncture a hose, suit etc. (hence the blunt end).

Large Knife: For me, I don’t think these have a place in the majority of today’s recreational diving but are the most common. I normally make the joke “You only carry these in case you come across an aggressive hungry shark, where you take it out, stab your buddy, swim to safety and tell the tale how your buddy sacrificed his life to save yours”. Sorry I will now get back to being objective! As per the small knife, these are normally for tackling specific objectives that normally require force and leverage hence my comment about not needed for general diving. While the knife can be used for many of the examples above, it will not perform as well as the others. Very much in diving it choosing the right tool for the job. Another use for this type of knife is in the hunting arena. It will have the same disadvantages of the other blunt knifes but with the additional issue of stabbing someone. An example I give is imagine you are trapped in a net (around your head), there is a swell so you are moving about a bit, its the UK so viz is a meter or 2, which would you be more comfortable to see? Your buddy swimming up with his huge knife out to cut you free or a pair of shears?
Storage: Arms, Waist Webbing, BCD/Dry suit Pockets (inside or out). I would suggest changing out the rubber straps that easily split to either bungee or thin webbing. In my view having one on your leg is the worst idea ever, as it becomes a huge entanglement issue. I have lost count of people I have seen caught in nets, kelp, catching it as they swim through a structure, catch it on coral etc. They are hard to reach in an emergency and are a real safety issue with weight belts. We have all seen divers with lose weight belts or belts being opened accidentally. Imagine a weight belt slipping down the legs of a diver, getting caught on the knife, this could potentially tie up their legs removing their ability to swim. This could happen in an emergency if the buddy didn’t fully release the belt properly. If you really want to carry a knife on your leg, i would strongly recommend strapping it to the inside. It reduces the issues above slightly and is actually easier to reach for most people.

I hope you enjoyed the read, and look forward to hearing other people’s thoughts on this topic. Always keen to learn about things I don’t know or never thought of.

Regulator – Pre Dive Checks

I wanted to share some things I do to try to be a safer diver. So in this post I wanted to share some additional Regulator checks I carry out before diving and what I teach to students. Please feel free to copy these checks or if you do anything else, I would love to know. So these checks are done while kitting up/packing kit the night before. (Will cover the 5m Safety Drill/Bubble check in another post).

1) Zero Pressure Check: Remove dust cap, and before connecting to tank. Use thumb or fingers to cover/block inflator hoses. Then try breathing through each regulator, it will be hard but not impossible. By blocking the hoses you are ensuring you sucking air all the way through the 1st Stage to 2nd Stage.
Reason: To ensure you can get that last 20-30 bar out of your tank in an emergency. If you cant breath through the Reg this means your Regs have problems and need servicing ie stuck or sticky valves/seats. This might not be apparent during a normal test as there will be 200+ Bar of pressure pushing its way through the system.
Example: Suddenly it all goes wrong underwater, you are buddy breathing and making an ascent to the surface you are at 50 bar and you think that’s enough we will make it. Half way the pressure has dropped to 30 and that 30 bar is not enough to push through the system, so now you are technically out of air.

2) Normal Pressure Check: As you turn on your air slowly, keep your Reg purge button depressed, and slowly release stopping the air. Once the Tank is fully open test your regulators as you would do normally (remember to get a buddy to breath of your alternative air source at the same time).
Reason: . Idea is to lengthen the life or your HP seat/valve in your first stage, therefore reducing the possible damage before a dive – many Regulators advise this in their manuals. By both divers breathing at the same time you can ensure the Regulators are in a well maintain state to support 2 divers.

2a IP Check (Intermediate Pressure): I only do this every 3 months or so or before a long weekend of diving. You can pick up an IP gauge that plugs into your inflation hose for about £15 to £20. Most IP pressures are set between 9-10 bar (please see your Reg manual). Similar to the normal pressure test you breath from your reg watching the IP gauge. The pressure should drop then once your breath has stop it should within a couple of seconds return and stop at the IP pressure. You are looking for IP creep, this is where when you stop breathing the pressure will return to the IP pressure but then continue to slowly creep upwards.
Reason: If this is happening it means there is problem with your first stage, normally the HP seat. If this seat wears out enough you could get a free flowing first 1st stage that will push the pressure up in the hoses, either bursting them or forcing open the 2nd stages. (If you have regulators that are upstream – not very common and you will know if you have them, this could blow the over pressure valve).

3) Negative Pressure Test: Turn your tank off and keep breathing from your Regulators slowly (Ensure inflation hoses are blocked as per step 1). There are 2 parts to this, 1st closely watch your pressure gauge, you checking that the needle is not sticking at any points. 2nd You should get to stage when you cant breath any air in.
Reason: If you can still breath this means there is a fault with your Regulators. Commonly (not always) this test identifies that one of the following is ripped and letting air in, if air is getting in that means water will get in. If the hole increases in size enough you could suddenly breath in a load of water (not the best thing to happen underwater). The mouth piece, the 2nd Stage Main Diaphragm or the Exhaust Diaphragm has a hole.

4) Leak Test: Turn the tank on and then off and slowly breath your Regulators down until you pressure gauge shows 10 bar. Then simply leave your kit alone and sort out the rest of your gear. Then check your gauge after 10 mins or so.
Reason: Pressure has dropped significantly – you have a leak somewhere in your Reg set. Pressure has increased – you have a leak in your tank valve. I use 10 bar, as its enough pressure to push out of a leak but low enough that if there is a leak in the tank valve the pressure is not high enough to act as a barrier. Also when I check its easy to remember 10 out 10 is a good result. (Keen to know what pressures other divers use and why).

I hope you may have found some of this useful, and would like to know if there is anything people do differently in relation to Regulator checks.

G-SAV