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.

Diving at Ponta do Ouro
Diving at Ponta do Ouro

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.

Bookshelf: A Field Guide to the Marine Animals of the Cape Peninsula

A Field Guide to the Marine Animals of the Cape Peninsula – Georgina Jones

A Field Guide to the Marine Animals of the Cape Peninsula
A Field Guide to the Marine Animals of the Cape Peninsula

This is the first (and can hold its own as the only) marine life book that I would recommend that a scuba diver in Cape Town purchases for their library of diving books.  It’s focused on the marine animals you’ll find in False Bay and on the Atlantic coast of the Cape Peninsula – a fairly small geographic region, but one with upwards of 150 dive sites and with incredible biological diversity. (The second book I recommend to local divers is Two Oceans, which has a far broader geographical focus and is thus less useful to Capetonian divers.)

The author, Georgina Jones, is a diver herself, and a member of the Southern Under Water Research Group (SURG), which published this book. SURG aims to bridge the gap between recreational divers and the scientific community, and apart from several fantastic book publications, their website provides a forum for divers to submit photographs of marine life for the experts to identify. Sightings of strange and exotic creatures (many of them at Tony’s favourite Long Beach hangout) are listed, too – often creatures from warmer waters up north get washed into False Bay and are then spotted by lucky divers.

The book has a photograph of each organism, and a brief description of its size, habitat, behaviour and feeding habits. The creatures are photographed in their natural environments, so the colours are representative and the creatures are alive (I didn’t realise how important this was until I used Rudy van der Elst’s book).

Two Oceans covers sea plants, and devotes more space to crabs, molluscs and the like than this book does, but particularly for beginner divers this isn’t an issue at all. It takes quite a few hours in the water before one discovers the joy of hydroids!

You can purchase this book from SURG – there are order details on their website and they will post it to you directly. Otherwise it’s available in good dive shops in Cape Town.

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!
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!

Bookshelf: The Dive Spots of Southern Africa

The Dive Spots of Southern Africa – Johan & Amilda Boshoff

Local divers Johan and Amilda Boshoff have compiled a fantastic dive guide covering the best locations in Southern Africa. It’s formatted and laid out especially for travellers, and I have used it to decide where to dive when visiting Durban and Knysna. The pages corresponding to the different provinces are colour coded, and there’s also general information at the start of the chapter on each area which would be super useful for tourists.

The guide is illustrated with gorgeous photographs – the ones of Marico Oog have made me determined to visit it next time I am in Johannesburg and surrounds. (Did I mention that inland dive sites are also covered?) The authors provide a star rating system as well as symbols indicating the entry type (boat, shore) and whether it’s a wreck dive. A symbol also indicates whether the site is suitable for snorkeling, which is useful if your travel buddies or family members like the sea but aren’t divers (yet)!

The Dive Spots of Southern Africa
The Dive Spots of Southern Africa - front and back covers

I’d recommend this book for diving visitors to Southern Africa, and also as a supplement to dive planning for local travellers. If you’re living somewhere and diving there often (like me in Cape Town), you’ll need something more comprehensive on a day-to-day basis (thank you Peter Southwood), but as a guide to what’s available when you decide to hit the road, this book is quite useful.

The book is available from Loot.co.za or Amazon.com. The Boshoffs’ website is here, with  a specific section devoted to the book.

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.

Diving at the Two Oceans Aquarium

For Tony’s birthday in June we spent a Sunday morning at the Two Oceans Aquarium at the Waterfront, diving in the I&J Predator Exhibit and in the Kelp Forest Exhibit. These were two of the best dives I’ve ever done. You need an Open Water or equivalent qualification for the predator tank, though I think you can do a (expensive?) DSD there too. For the kelp forest you need an Advanced qualification, as even though it’s only 6 metres deep, it’s very surgy.

On both these dives, you are on view to the public. It’s fun to wave at the kids through the windows of the displays. They are very excited to see real live SCUBA DIVERS in the water with all the fish. Needless to say, the scuba divers were very excited to be there!

Youtube videos for both dives can be found here.

Kelp Forest Exhibit

We started in the kelp forest – you wind your way up to the roof of the aquarium and drop into the water off a small wooden platform. This exhibit completely is open to the air, since it’s comprised of vegetation and sea creatures found in Cape waters, and because kelp loves sunlight. Kelp also likes water movement, so there are a variety of devices to keep the water moving – dump buckets, a plunger, and some pumps. This makes it quite choppy on the surface and quite surgy below. (Fascinating fact: since kelp cleans the waste products – such as ammonia – out of the seawater by filtering it, a lot of the aquarium’s water is passed through the kelp tank on its way to other exhibits.)

The exhibit has live kelp that is actually growing, which is quite an achievement, but you’re not supposed to hang onto it the way I sometimes do in the open ocean! The tank is packed to the brim with white steenbras (my absolute favourite), red stumpnose, galjoen, zebra, roman, shysharks, fransmadam, and even a gully shark if you can spot him. The fish are huge, many of them much larger than any I’ve seen in the ocean. I was extremely fortunate to be allowed to feed them – I was given a small bag of squid pieces and sardines, and the fish gathered around me as I knelt on the bottom. It was wonderful, so busy and colourful. They weren’t shy, bumping into my legs and BCD once they’d realised I had lunch with me. There’s a hilarious finger-biting episode at around 2:45 minutes in this video:

The water is cold, and the tank isn’t actually very big. There are nice swim throughs between the rocks (made of fibreglass) and the kelp. The visibility isn’t perfect as the water is so highly aerated, and there are little bubbles of air everywhere. But it’s a thrilling dive and a very rare opportunity to get so close to so many beautiful fish.

Dive date: 6 June 2010

Air temperature: 18 degrees

Water temperature: 14 degrees

Maximum depth: 5.7 metres

Visibility: 10 metres

Dive duration: 27 minutes

I&J Predator Exhibit

The second dive we did was in the predator tank, which is a lot warmer than the kelp forest. On this dive, the Divemaster was armed with a piece of broomstick to “guide” the sharks away if they were to bother us. There are five ragged toothed sharks in the exhibit, none more than two and a half metres long. I think they’re all female. They cruise round and round in circles, looking completely awesome. I spent a long time just sitting on the floor of the tank watching them.

The other magnificent inhabitants of this tank are the sting rays. There’s Olive, a giant (and I mean GIANT) short-tailed sting ray like we see at Long Beach and Miller’s Point in summer, and a whole host of small (the sort of size that makes you want to take them home as pets) devil rays. Tony spent a significant part of the dive (while I was sitting watching sharks) chasing tiny rays around with his camera set on video.

In the corner of the tank we met the loggerhead turtle. She was lying next to a water vent, with her head in the corner. I was allowed to touch her on her neck (it felt really soft, and I felt lucky). I wasn’t convinced that she was a happy girl – she looked kind of depressed. Our DM said she gets more active when the water temperature increases, and sure enough I saw her swimming happily past the glass in the predator tank two weeks ago, when I went for my Saturday morning training at the aquarium.

The tank also contains musselcrackers, garrick, yellowtail, and (at the moment, but not when we dived in it) the remains of a sardine baitball.

The only moment when I got a bit of a fright was when we were surfacing against the rocks in the middle of the tank, and I omitted to look where I was going: straight into the path of a raggie. And sharks don’t generally get out of the way! Fortunately our DM had seen me behaving like a space cadet and “guided” the shark off to the side (since I wasn’t able to interrupt my ascent quickly enough).

Dive date: 6 June 2010

Air temperature: 16 degrees

Water temperature: 18 degrees

Maximum depth: 5 metres

Visibility: 25  metres

Dive duration: 35 minutes

Bookshelf: Ocean: An Illustrated Atlas

Ocean: An Illustrated Atlas – Sylvia Earle & Linda Glover

Ocean: An Illustrated Atlas
Ocean: An Illustrated Atlas

I eyed this book for weeks and weeks before finally succumbing and placing an order online (get it here). It’s a National Geographic publication, and – as one would expect – absolutely magnificent. It’s mainly about the detailed ocean maps, but there are articles on each ocean, and on topics such as the impact of climate change, conservation and deep sea exploration.

Sylvia Earle is incredibly impressive – a living legend (according to both the US Library of Congress, and yours truly).  She has a long history of work in and on behalf of the world’s oceans, holds several diving records (she’s hardcore) and is a world-renowned scientist and explorer. She’s an expert on the subject of oil spills, and is – I think – soon set to release a book on the latest BP-led fiasco in the Gulf of Mexico.  She also holds the designation of Explorer-in-Residence at National Geographic, which sounds both like a contradiction in terms and like the coolest job in the world.

I spent most of my time in this book poring over the maps, and picking up nuggets of (potentially) useful information about where the sea is deep, where it’s shallow, and what the bottom profile of a whole host of international dive sites is like. There are water temperature maps (myriad rainbow shades showing the spectrum from freezing cold water in indigo, to lovely warm water in red). There are fascinating charts showing the position of the various (and multitudinous) information collecting devices (buoys and others) all over the world’s oceans. I also learned, thanks to one of the detailed double-page maps, that the ocean’s currents are far more complex than primary school geography led me to believe… The update on the state of oceanography and deep sea exploration was also fascinating. I was awed to discover that the average – that’s AVERAGE – depth of the world’s oceans is about 4 kilometres. As recreational open-circuit scuba divers, we can go to 40 metres with the appropriate qualification. That’s hardly scratching the surface.

This is a magnificent coffee table book, but not just one that you’ll leave lying about and not return to over and over. The impression it left me with was twofold: one, how vast and varied our oceans are. The second impression was of how little we know about what’s under the waves. That is kind of thrilling!

You can obtain a copy here if you’re in South Africa, otherwise click here.

Exploring: North Battery Pipeline

Tony has been eyeing the pipeline just south of the Lower North Battery (that collection of navy buildings with gun turrets on the Main Road just before you get into Simon’s Town) for some time. It’s north of Long Beach and further north than the wreck of the Brunswick. Even though I was coming down with what turned out to be a vicious bout of flu, I was determined to get in the water (I reckoned I was getting sick anyway…) so we went exploring one Sunday morning in midwinter.

We parked the cars on the southern side of the North Battery – there’s a little driveway and we pulled them out of the way onto the grass (here it is on Google Maps). There’s also space for just one car, pulled right off the road, right above the entry point. From there it’s a bit of a walk along the pavement, down a slope, over the railway line and then down to where the pipeline starts. You can see the single-car space next to the piece of fence, and below it the start of the pipeline to the left of the rocky outcrop in this image from Google Maps.

The entry isn’t too bad. There’s a barnacle-encrusted concrete promontory that we sat on to put our fins on, and then (theoretically) dropped forwards into the water, which was just over waist deep. While putting on my fins I got washed over backwards onto the wrong side of the promontory (thank you for my thick wetsuit!) but that turned out to be fine, as it was sheltered, and eventually I managed to get clear of the swell and kelp with a little bit of effort.

North Battery Pipeline entry point
North Battery Pipeline entry point

We followed the pipeline straight out to sea. It’s not very long, but quite undisturbed, with lots of abalone and rock lobsters. There are one or two leaks in the pipeline, emitting a brownish liquid whose origins we preferred not to speculate on… it looked warm, or oily, because it shimmered a bit before mixing with the surrounding water. Tony thought it might be mountain water (tannins causing the brown colour). Hope so. Right at the end of the pipeline the visibility got really poor from all the stuff flowing out, so we turned south.

It’s all sand south of the pipeline, with lots of beautiful anemones and countless sluggish puffer fish buried in the sand. We turned after a hundred metres or so, and swam back closer in to shore. There we found what looks like the remains of a ship – four or five big rusty bits of iron sticking out of the sand in relatively shallow water. I don’t think it’s part of the Brunswick – I think we were too far north – but it could be.

Verdict: Glad we checked it out. Lots to see on the pipeline (good for macro photography) but be careful about the poor visibility at places. Curious about the bits of ship (I assume) inshore, south of the pipeline.

Dive date: 18 July 2010

Air temperature: 17 degrees

Water temperature: 12 degrees

Maximum depth: 6.5 metres

Visibility: 5 metres

Dive duration: 30 minutes

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.

Deep dive
Ascending from the almost disastrous deep dive on Atlantis in Ponta do Ouro. Note the hang tank of pure oxygen.

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.