Tony – Page 77 – Learn to Dive Today Blog

Oral inflation

As I have mentioned before, problems arise when we don’t follow our training. I was working at a busy resort as skipper, Divemaster and Instructor. On a busy day I would kit up at 6.00am, launch the boat, dive, hit the beach to collect the next group, quickly change cylinders and head straight back out again to dive, sometimes doing four or five dives a day. We would only be done by early evening so there was no time for kit maintenance.

I had a problem with my inflator during the last dive of the day and quickly replaced it with a spare from my dusty tool kit late in the evening. Being too tired to fetch a cylinder I did not test it (mistake number one). The following morning I was distracted whilst kitting up and did not test it (mistake number two). The first dive of the day was to 40 metres. Being skipper and Divemaster meant I did not have too much time on the boat for a buddy check (mistake number three).

Half way down to the reef I intended slowing my descent and found my inflator was not working. Ah, no problem, I teach people how to orally inflate their BCD every time I have a student so I was not concerned. What I had forgotten was the pressure exerted at 40 metres on the bladder of your BCD is way more than you can imagine and oral inflation at that depth is a lot more difficult than it is at 18 metres. Instead of a few small breaths to reduce my descent it took a good eight or ten and by this time I was ready to bounce off the bottom.

The moral of my story: remember to always do a buddy check even if you have to do it on yourself. Don’t skip this step! And don’t change anything on your kit without testing it prior to dropping off a boat.

Out of air!

Out of air emergencies should not happen. Diving safely includes being sure that you have checked everything yourself, doing a buddy check and diving within your own personal limits. Always avoid making too many changes to your gear configuration and don’t test more than one new item at a time unless you are in shallow, confined water.

Most incidents are a culmination of several small mishaps and would most likely not have occurred had just one error being omitted. The other issue to be aware of is trusting your training and avoid thinking you know better. Here’s why…

I was diving in Mozambique, did a backward roll, and a negative entry (that’s when you don’t hang around on the surface with an inflated BCD, but start your descent immediately). Now, doing negative entries is not ideal, but the surface current was strong, we were diving a small reef and I wanted to get down quickly. So after the roll I finned down head first as fast as I could, without a buddy… Mistakes number one and two.

At 18 meters I found breathing to be difficult. Having just over-exerted myself I stopped to catch my breath but found as I reached the end of my breath my regulator stopped giving me air. Slow breaths were okay but it would not deliver what I needed. I instinctively looked at my pressure gauge, plenty of air in the cylinder but the needle dropped off as I took a deep breath.

“AHA my cylinder is not all the way open,” I thought so I reached up to try and check. It felt open, but convinced I was not doing it properly I took my kit off, held it in front of me and checked. The cylinder was all the way open, and now suddenly I was not getting air at all. I swam to the surface, slowing at about 8 metres to grab a few breaths from a buddy pair descending slowly.

On the surface I signaled the boat and whilst remaining in the water had the top man change my regulators – mistake number three. Straight back down to 18 metres I went, breathing normally and as soon as I turned face down to scan the sea for the group I ran out of air again. Back to the surface as fast as possible! A CESA from 18 metres is relatively difficult once you are stressed and short of breath from over exertion.

On the second descent logic was telling me the problem had to be my cylinder, but arguing with myself I dismissed this as I had serviced my cylinder less than three months prior to this and felt it could not possibly be at fault.

Back in camp I stripped my pillar valve and found it to be blocked with rust and sand. How could this be?

After investigating it turns out the cylinder was dropped from a vehicle a few weeks before this by the compressor operator. The pillar valve was damaged, so they drained it in a hurry, causing condensation, dropped it again in the sand, rinsed it with the water used for cooling cylinders whilst filling (salty water), emptied the water out, replaced the pillar valve with a used one, without a snorkel (a small pipe that runs from the bottom of the pillar valve into the cylinder). I got it back full of air unaware of the incident. The salty water inside rusted the cylinder, the absence of a snorkel meant that every time I was pointed head down the scales inside slowly drifted into the pillar valve until it was totally blocked.

It is not unusual for a little spot of rust to develop in a cylinder. It’s not ideal but it won’t kill you. However a snorkel ensures the pillar valve is supplied with clean air and the scales are kept out – in my situation in Mozambique, the scales would have settled around the top of the snorkel where it attaches to the pillar valve, instead of blocking the valve completely. The other end of the snorkel would have been a bit further into the cylinder, drawing clean air. When I took my cylinders to Orca Industries recently for their annual maintenance, I was very impressed that they insisted on checking each one for snorkels, and fitting them if they were absent.

Newsletter: Treasure Hunting, Whales, Sodwana

Hi everyone

The weekend is closing fast, today we saw 14 whales in the bay, of which four were close to Long Beach and three at the Clan Stuart. They have been hanging around for about two weeks now and don’t look set to leave soon. It is very likely we will dive with them on Saturday as the weather is looking amazing, sunny, 27 degrees and hardly a breath of wind.

I have a posse of Discover Scuba Diving candidates on Saturday, so I will dive long beach in the morning. Afternoon dives will be dependent on where the whales are and we will hopefully be able to get them on camera…on a dive.

Night dive on Saturday as usual, meet at long beach at 6.00 pm. Remember I have torches and cyalumes.

I have good news and bad news:

The good news is that the Sodwana dive trip is filling up fast, the water temperature there today was 22 degrees, flat seas and sunny skies…. Hmm, it’s not too late to decide to come along, a cheaper warm tropical dive trip will be hard to find. We are all arriving in Durban at about the same time so we will share hire cars to keep costs down. There is also an option of diving Aliwal shoal on the Monday… shout soon if you are interested.

More good news, I have been asked if we would be interested in diving the Rietvlei Nature Reserve and water sport facility. Matt works for a company that runs a boat there and they have lost a very valuable stainless steel propeller. It would require some search and recovery techniques and we would be very popular and possibly famous if we find it (the reward may be as much as a case of beer). We would need to be three teams and anyone doing the dive will receive a search and recovery adventure dive log in their log books, free, one less dive on the way to Advanced diver…

Besides, there must be so much treasure down there as it is a seldom dived area… no crocs I assure you. Sunday would be good for this dive.

The bad news is that from tomorrow anyone diving with me will need to ensure their hair is proper, make-up done, dive kit polished and shiny, and they behave underwater, and on the beach… I have a new video camera and will be hunting for footage of you all behaving badly underwater, something I can put on YouTube, or use to embarrass you. If you think you are behaving foolishly and no-one saw, beware, so Tami, no shark wrestling, Clare, no groping of unsuspecting puffer fish, Maurice, no more crayfish in your pockets, and then to all of those that molest poor innocent pipe fish… be warned… luckily the biggest offender will be holding the camera…

Don’t forget all divers need a dive permit, get yours before they get you! Available at the Post Office – take your ID book.

Dive Like a Fish - Learn to Dive Today!

Tony Lindeque
076 817 1099
www.learntodivetoday.co.za
www.learntodivetoday.co.za/blog
Diving is addictive!

Breathing underwater

Most divers ask “how long will my air last?” There are several variables to this but primary factors are how much air you start with, the depth you intend diving to, and your rate of consumption.

Body size is important, and activity underwater and stress levels are also factors. Fitness is not necessarily an huge factor. An unfit overweight diver that moves slowly in a relaxed manner will consume less air than an elite athlete with a high stress level finning inefficiently.

A 12 litre cylinder filled to 200 bar will have 2400 litres of air. If your breathing rate is 20 litres a minute on the surface you could use the cylinder for 120 minutes. The same cylinder at 30 metres will only last 30 minutes.

Cylinders — If you decide to purchase your own cylinder, it’s critical to maintain it

The technical jargon to work out your predicted air consumption per minute is as follows:

The volume of the tank is divided by the breathing rate multiplied by the absolute pressure of the depth at which it is breathed.

Afterwards, you can calculate your realised or actual breathing rate for a particular dive. Take the amount of air you consumed on the dive in bar, and work out how many litres you used using the above information. You can work out how many litres of air you used per minute by dividing the number of litres by the dive time. You can track your air consumption, and tie it to a variety of factors – how you felt on the day, your weighting, how your gear was set up, and of course depth – if you keep proper records in your logbook for each dive.

Plan your dive and dive your plan

Three divers approached me at the dive centre one day, requesting I take them to a dive site where they could dive to 60 metres. They wanted to test some new equipment configurations. Two were certified advanced Nitrox divers, qualified deep technical divers and had made several dives to over a hundred metres… in a lake. The third diver, like myself, was qualified to dive to 40 metres.

So we draw up a plan: they will dive to 60 metres, spend 6 minutes at that depth, ascend to 50 metres and spend 5 minutes there, then ascend to 40 metres 5 minutes thereafter and so on until the reached 6 metres where they would switch to pure oxygen to reduce the deco stop time as the current at this site is strong. The third diver and myself would meet them at 40metres.

Using a software program called V Planner we calculated that including the descent time and ascent times for each stage, at a controlled rate, we would enter the water precisely 16 minutes after they started their dive and we would meet them at 40 metres. We would then all be together for the next 30 minutes, ascending with them to their 6 metre safety stop, ensure they had both switched to pure oxygen and then leave them and return to the boat.

The plan was that we would spend 6 minutes on our descent to 40 metres and all four of us would reach 40 metres together. They were made to clearly understand that should they have a problem at any depth deeper than 40 metres we would not be able to help them as we were diving 12 litre steel cylinders on a Nitrox 32% mix, limiting our depth – and what’s more we did not have the qualifications to go to 60 metres.

We discussed the plan in great detail and everyone was set. A red SMB would be hoisted if they experienced any difficulty and a yellow would be released once we met at 40 metres.

Mistakes happen

We started our descent on time, and watching my dive computer and timer I descended at the agreed rate. My buddy, however, did not. He descended way too fast. Believing that they would be in control of their dive he descended very fast and joined them, ahead of schedule at a depth of 55 metres. They were 3 minutes behind schedule as they had struggled to come to terms with the ocean current. Now we had a problem. I waited at 40 metres, but they arrived late, and this meant I would risk going into deco before we left for the 30 metre stop.

At this point my buddy ran out of air. He was closer to the deep divers as he was reading their slates, so he grabbed the first regulator he could see: the deco tank regulator, filled with pure oxygen. At depth oxygen is toxic and can kill you in a matter of minutes. I grabbed it out of his mouth, so he grabbed my regulator out of my mouth as he was now starting to panic. He was holding onto me so tight I could not reach my octo so I reached for the octo of another diver. So here we were three divers locked together at 40 metres, each with a regulator in our mouths that belonged to someone else. I managed to get him calmed and off my cylinder and onto the octo of the deep diver with the most air. Now back to normal, we started our ascent and did the required safety stops, reached the 6 metre stop for them to switch to oxygen and headed for the surface. I reached the surface with 10 bar in my tank.

My buddy had been to 55 m on a Nitrox mix of 32%. The maximum safe depth for this blend is 40 metres. He had almost sucked on a cylinder of oxygen at 40 metres, this is a lethal dose at depth. Mistakes happen. Be meticulous with dive planning, rehearse your incident scenarios and make sure you dive your plan.

Wreck penetration

Once you embark on the Wreck Specialty Diver course you can choose to include wreck penetration if you wish.

There is more to this aspect than just having a big torch! Passages deigned for walking along become very tight spaces if the ship is lying on its side and a once narrow walk way will have you crawling along the bottom of it while your tank scrapes the top, dislodging rust from above and silt from below – reducing visibility to zero despite your huge light.

Once in a wreck you need to move very slowly as the diver behind you will not have a good time swimming in the silt cloud you create. Your bubbles are also enough to create a cascade of flaked rust in some instances. It is extremely important to use a reel and line, tied off at the entrance. You belay the line at various points to prevent the line following a route you can’t navigate on your return. If you don’t do this, the line will find the shortest route through the wreck behind you – not necessarily person-sized! Cyalumes attached to the line are useful just as a back up torch or three is also an essential requirement.

Always ensure you have studied a drawing of the layout of the sections you plan to penetrate. The MV Aster wreck just outside Hout Bay Harbour was purposely scuttled by divers, for divers. As a result detailed drawings of the interior of the wreck exist, and it is an ideal site for training in wreck penetration.

Finning

Not getting anywhere

Often divers find that the hi-tech latest fins they bought for a packet are not giving them the pleasure and speed they thought. The slightest current has them finning as fast as possible, consuming air rapidly and not keeping up with the other divers.

A decent pair of fins allows you to use your most powerful muscle, your thigh muscles. If you fin like you ride a bicycle you will go nowhere.

The downward stroke delivers the most propulsion. Keep your leg straight and kick down slowly, bending the knee slightly on the upward stroke. You will find long leisurely fin strokes will use little energy and give you exceptional forward movement.

It is also important you have a good horizontal profile in the water because if you are swimming almost upright across the bottom you create a huge amount of resistance. Stay streamlined, keep your arms at your side and ensure all your gear is tucked and clipped close to your body.

Big fins — Ensure you have a good horizontal profile in the water (hint: this isn't good)

Entry techniques

It is common for similar dive sites to have a completely different entry styles, and shore diving is no different.

Boat diving will in most instances involve either a backward roll or a giant stride depending on the size of the boat and the bottom contours. A giant stride off a jetty onto a submerged object is no fun.

A giant stride can be a long drop to the water on a large boat that does not have a dive platform and it is important to ensure the area is clear before you leap.

Doing a backward roll off an inflatable has its hazards. Ensure everyone rolls at the same time to avoid landing on the person next to you. Even the slightest hesitation can result in the boat drifting slightly and you landing on a diver. Ensure that your BCD is inflated, and that you have your hand over your regulator with your fingers on your mask to hold them in place. If someone does land on you, don’t panic – just relax, remember to breathe, and wait to pop to the surface.

Underwater below the boat — It can get crowded around the boat, which is why it's important to roll off exactly when the skipper tells you to

Shore entries may have you walking through the surf to get some depth and even a small wave can knock you off your feet. Clambering over rocks at some dive sites will find you slipping and sliding about so watch the waves and time your entry and exits.

If you aren’t already wearing your mask, make sure it’s around your neck or with the strap pushed well up over your forearm, NOT on top of your head or inside a fin! Or preferably on your face already. Ensure you have your fins clipped correctly and slide the straps up over your forearm so that if you stumble and place your hands instinctively in front of you they shouldn’t get lost. As soon as you are waist deep don your fins and swim away from the shore.

Irrespective of the style of entry, before committing to enter the water ensure your gear is clipped, weight belt tight, zipped up suits and gloves are on. Ensure your mask is on and secure and your regulator firmly in your mouth, This will ensure that should you be toppled over by a wave you will be able to see and breathe. Likewise when doing a giant stride or backward roll, place one hand on your weight belt, the other over your face with the palm holding your regulator in and the fingers holding your mask firmly on your face.

Wreck diving

There is just something so intriguing about diving a wreck and this need not be limited to ships alone. This tank wreck in the Red Sea is an amazing dive.

Sunken tank in Jordan — This tank was placed as an artificial reef by order of the King of Jordan, who is a diving fanatic!

Wrecks all have a story to tell. Some are there from navigational errors (like the Kakapo on Long Beach, Noordhoek), some from mechanical faults, some from war battles (like the HNMS Bato off Long Beach, Simon’s Town), many of them as a result of bad weather (like the Clan Stuart) and some wrecks are the result of a planned scuttling to form an artificial reef (for example, the Smitswinkel Bay wrecks).

No matter how it got there, exploring a wreck is fascinating and within months of its arrival marine life forms move in and make the nooks and crannies home. Corals, sponges, sea anemones – to name a few – all appear and grow within months of the wreck’s arrival. Wrecks can sometimes become home to more species than you see on a nearby reef purely due to the wreck’s size, giving juveniles far more protection from rough weather than a reef can.

Despite the allure of the many opening and overhangs, wreck diving has its own set of hazards and without proper training it is important to stay out of any overhead environments. It is also critical to avoid becoming entangled in the myriad of cables, ropes, chains and often fishing tackle that can sometimes be draped over a wreck. When you start wreck diving you will most likely be content to swim around the outside and be awed by the size of some wrecks, once majestically sailing the seas, brightly painted and full of noise and life. Now they lie silent, rusty and overgrown, but still teeming with life.

A powerful dive light is a must if you want to peer inside holes and hatches, but be wary as your light can often disturb some huge creature who will buzz by you startled and dazed by your light, as you are blocking the exit.

Newsletter: Sodwana trip and diving this weekend

Hi everyone,

Sodwana Bay

The trip to Sodwana is on for the weekend of 8th, 9th and 10th of October. I have attached a breakdown of the costs with as much detail as possible (courtesy of Clare) [Note to blog readers: email me for this]. To secure the booking I need you to think quick and respond as soon as possible as I need to know the numbers. It is open to anyone that dives, students and friends of mine as well as any of your friends. The idea group size will be 8 -10 as this way we will fill a boat and therefore get to decide on the dive site. All the dives go to 2 Mile Reef, and almost every dive on this reef is suitable for Open Water divers. Sodwana claims to be the best dive site in southern Africa and rightly so, it is also the town where they have T-shirts labeled: a small drinking town with a diving problem…

Diving this weekend

I ran a competition with a Discover Scuba Diving experience for two and the winners will possibly venture into the water on Saturday. The Rescue course starts this weekend and in between we will have a fun dive to the Clan Stuart or cowsharks. Swell dependent. Saturday night, I will feed my addiction to night diving, meet at Long Beach at 6.00pm.

Sunday I am hoping to do a deep wreck dive for the Advanced students and will confirm this with the charter during the course of the day (the wind may factor this out). If you do wish to do boat dives I need to know by Wednesday as the boat launch schedule comes out on Thursday morning and the boats often fill very quickly.

I have ventured into the blog world, see link below, the idea being to post diving related info and create a forum for questions, so feel free to read, post, comment, correct me and ask away, if I do not have the answer I will find it for you and add my theories and opinions… risky I know…

Tony Lindeque
076 817 1099
www.learntodivetoday.co.za
www.learntodivetoday.co.za/blog