Surface interval

Newsletter: Smoke on the water

Hi divers

Weekend dive plans

Sunday: Boat or shore dives, conditions dependent!

We have had terrific conditions all week and have been taking full advantage. False Bay is cleanish and warmish. Visibility has varied from site to site but the bay is full of life. On Tueday we spent our surface interval time photographing sea swallows at Batsata Maze. Wednesday’s surface interval was spent filming giant short tail sting rays at Millers Point, and today we were fortunate enough to have two orcas swim by close inshore whilst the divers were on the SAS Pietermaritzburg this morning. Who knows what we will see tomorrow!

Giant short tailed sting ray behind the boat at Millers Point

Sadly the diving today was somewhat overshadowed by the raging fire that descended on Simon’s Town with the westerly wind, despite the best efforts of many firefighters. Watching from the water you could see the speed at which the fire traveled and I doubt anything other than a thundershower was going to slow it down. On the run back into Simon’s Town we went through really thick smoke.

The weekend, however, does not look too rosy. At cowsharks this afternoon the swell was quite noticeable and although it stays at 3 metres for most of tomorrow, the forecast is for 5-6 metres on Saturday. It seldom reaches the height in the forecast but even at 4-5 metres diving becomes less than great. Surge and low viz are on the cards. I think there will be a better than good chance that Sunday will be semi-decent so I will provisionally schedule diving, either from the boat or perhaps a shore dive or two… Text me if you want to join and I’ll keep you posted.

Diarise

Don’t forget the Shark Spotters fundraiser on Sunday – should be fun!

regards

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

Diving is addictive!

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Suunto D6 in full panic mode (part II)

Yesterday I told you about a dive on Doodles, a reef in southern Mozambique, during our trip to Ponta do Ouro last month. Doodles has a maximum depth of about 14 metres. After forty five minutes’ dive time, my Suunto D6 began to register extreme depths (89 metres maximum), and to give various instructions about decompression ceilings and times, accompanied by strident warnings about exceeding my PPO2.

While annoying and potentially dangerous to lose the services of my dive computer mid-dive, it was also an excellent learning opportunity. Because I usually try quite hard to be safe and not to upset my computer, and dive within the conservative, recreational limits that I am trained for, I never get to see any of this behaviour from the instrument. (Fortunately the dive was shallow and I still had plenty of no-decompression time left so it was far from an emergency situation.)

After the dive, I soaked the computer in warm fresh water, and it gradually came out of dive mode over a period of about ninety minutes. During the course of this simulated ascent, the required decompression times and depths calculated by the algorithm were not adhered to, so the computer entered an error mode, which, according to the manual, indicates that “the risk of DCI has greatly increased.” (In fact, from all the beeping and flashing, I suspect the computer thought I was dead or close to it.) This error mode does two things: it disables the dive planning capabilities of the computer, and it locks you out of dive mode for 48 hours.

I had never gotten the computer into this state before, so I was keen to see how it behaved when I took it on a dive in error mode. You can see in the photo above that I am wearing Tony’s Mares Nemo Wide (aka the flatscreen TV) to give me actual information about my no-decompression time, depth and dive time, but I took my D6 along for the ride. It is in gauge mode; this means it gives you only measurements, and is the setting a free diver might use.

The measurements available in gauge mode are: depth (18.4 metres in the photo above), the maximum depth you’ve been to on this dive (19.9 metres), an elapsed dive time (17 minutes), and water temperature (not shown) but it refuses to calculate a no-decompression limit for you. This would usually appear where the Er appears in the picture above.

Depth profile (with warnings)

For your enjoyment, here’s another screen shot of the dive profile from MacDive, with the warnings expanded. Click on the image to see it full size. It is clear that the first warning beeps I heard during the dive were because of elevated PPO2 levels. At 89 metres the device immediately put me in deco, and then as it “ascended” fairly rapidly, it gave a warning about oxygen toxicity (OLF or oxygen limit fraction as used in the Suunto algorithm) and an ascent rate warning. On the right, at about 10 metres, a warning is given that the depth is still below the required level to complete the decompression.

All the green circular icons appearing around the middle of my dive, where the computer thought I was at 35 metres, indicate that the computer registered that I surfaced, but not for long enough to show on the dive profile. Weird!

My D6 remained angry for 48 hours after the dive at Doodles; by this time, we had finished our diving for the week. I’m not sure whether the problem with the pressure sensor is a permanent one (requiring repairs, a service or a new dive computer), or whether it was just dirty or stuck and will have resolved itself next time I dive with the instrument. I’ll be wearing a spare dive computer when I do, just in case.

Sodwana 2014 trip report

Our third Sodwana trip (prior ones were in October 2010 and April 2011, with a Mozambique trip and a Durban trip in between) was from 26-30 April 2014. As usual we flew from Cape Town to Durban, rented vehicles (three cars between ten of us – two other reprobates drove ALL the way from Cape Town, although we suspect Shane hitched a lift on a car carrier for part of the way…) and drove the 350 kilometres from Durban to Sodwana. We stopped in Ballito for food, as we were planning to self cater.

Coral Divers was our destination. Most of us had already dived with them on prior trips (Angie even learned to dive there!), and their position inside the park and excellent facilities and staff led us to choose to dive with them again. They have a gazebo on the beach, regular transport between the camp and the beach, and dive planning and organisation runs like clockwork. Our only quibble this time around was that their school rental gear – which several of our divers made use of – was in quite poor condition. Matthijs tried four different masks before he found one that didn’t leak, and the well ventilated wetsuits left something to be desired. Fortunately the water was a comfortable 25 degrees!

On the tractor heading to the beach - picture by Otti — On the tractor heading to the beach – picture by Otti

We did six dives over three days, all on Two Mile reef. This is the cheapest option, and if conditions are dubious (as they were on our first day on the water), the best option. The further reefs (Five, Seven and Nine Mile) are magnificent, but require excellent buoyancy skills from visiting divers to protect the coral there, as well as favourable sea conditions for the longer boat ride.

The dives are for 50 minutes or until you reach 50 bar of air, whichever comes first. We visited mostly shallow sites (some of the Advanced divers did a deep dive on one of the days) so we were able to dive for a full 50 minutes most of the time. Because we were a group of twelve, we were generally split across two boats. We did manage some dives where we were all together at the same site, which was lots of fun! Some of the dives were lovely drift dives, which are fantastic because you use so little air. The surge (which has previously bedevilled me in Sodwana) was only severe on one of the days we dived.

After our two morning dives each day, we ate and then napped (me) or went exploring. In the evenings we braaied, cooked in the communal kitchen or ordered from the on site restaurant, and actually ended up going to bed fairly early. This was partly to escape Gerard when he got out of hand (on one notable occasion!), and partly because we were completely exhausted from our dives. We were also getting up very early to be ready to head down to the beach at 0645 each day.

It was a pleasure to spend time with such hilarious and interesting people, to do lovely long, warm, colourful dives, and to walk around in shorts and a t shirt while a warm 28 degree breeze blew. I hadn’t really scuba dived since last December, so it was great to get back into it again and remember how it’s done. Unfortunately I didn’t take many (or many nice…) photos underwater, as I was struggling with my (own, not rented) mask and I also initially didn’t feel confident enough to get close to anything. Once I settled my buoyancy – on the last day, alas! – I got going a bit more with my camera.

At the end of our trip, we said good bye to the other divers, and Tony and I stuck around in northern KwaZulu Natal to go to the bush for a couple of days. That’s another story…

Red Sea trip photos: diving from a liveaboard

Here are some photos to show you what it’s like to dive off a liveaboard. They were taken on our Red Sea trip in October. The centre of the diving activity was the dive deck at the lower level of the boat, at the back. There we hung our wetsuits, and we each had a cylinder and a box to keep our loose bits of gear in. We used the same cylinder throughout the entire trip, and the crew used the long hoses of the compressor to fill our tins right where they stood. We didn’t unbuckle our BCDs from our cylinders once.

A black (air) or green (Nitrox) tag around the neck of our cylinders indicated what gas we were diving with. We used Nitrox throughout. A numbered tag attached to the shoulder of our BCDs enabled the crew to keep track of who had returned from their dive. They also wrote down our dive times and maximum depths for each dive, and we signed those figures off each evening. This is in case of an accident – they know what your dive profile is for the week.

Map for dive briefing of Shark and Yolanda Reef

The crew getting ready to tie the boat up for the night from a Zodiac

Traffic on the dive deck before a night dive

The board used for tracking divers and gas mixes

Divers setting off for a dive on a Zodiac

Climbing out of the water at the dive ladders

Liveaboards at Sha'ab Abu Nuhas — Liveaboards at Sha’ab Abu Nuhas

The camera table at the back of the dive deck

There were dives before breakfast, after breakfast, after lunch, and at night. On the first and last days we did three and two dives, respectively. I managed three dives a day. Christo did four! Most of us skipped a dive here and there, owing to fatigue, illness (don’t drink the tap or sea water, is all I can say), and general laziness! The briefings were detailed, with maps or slideshows to familiarise us with each dive site. We were told what creatures to look out for, and where they like to hide. For wrecks that could be penetrated, the dive guides explained the preferred route more than once.

After getting into our wetsuits we sat down in front of our kit, shrugged it on with the help of one of the crew, and walked down to the dive deck. There we either put our fins and mask on and giant strided into the water, or held our fins and climbed onto one of the Zodiacs to be driven a short distance to the dive site. This technique was used at busy sites where there were many other liveaboards already anchored, or locations where it wasn’t safe for the big boat to go.

To get out of the water we were either fetched by a Zodiac, or we returned to the back of the liveaboard and climbed up the dive ladders in our full kit. Helping hands were ready to assist us with our fins. We’d put our kit back, hang up our wetsuits, put cameras into the rinsing container on the dive deck, and then eat. Every dive was followed by food! And often, a nap.

At times strong currents had us hanging onto lines down to a wreck, and this also made getting back to the liveaboard a challenge at times. On one occasion the current was so strong that I wasn’t sure I’d make it from the line tied to the corner of the stern onto the ladder in the middle of the stern – a distance of two metres – without getting swept away. Some acrobatics and long arm stretches from Tony saved the day!

The process of diving off a liveaboard is far less strenuous than diving in Cape Town, which is why we could still walk after doing three or four dives a day. For one thing, the warm water means you get far less fatigued, and you use less air, too. The crew were extremely helpful on our trip, even zipping our wetsuits and providing soapy water when pulling on our thick cold water Trilastic suits seemed too much like hard work!

Red Sea 2013 trip report

Me, Christo, Kate and Veronica on the sundeck

We returned from our Red Sea liveaboard trip on Sunday, and have been slowly returning to normal life (essentially doing things other than eating, sleeping, diving in warm water with magnificent visibility, and lounging around on deck like millionaires). It’s been tough.

Two of the blue o two liveaboards at the jetty

The itinerary we followed was the Northern Wrecks and Reefs one offered by blue o two. Our vessel was M/Y blue Melody, on the right in the photo above. We dived wrecks like the Thistlegorm, Giannis D, and Chrisoula K, and a number of reefs. We did a couple of spectacular drift dives, and on most of the wrecks there was the opportunity to go inside for the suitably qualified. It was compulsory to dive with an SMB. The most memorable reef dives were done inside the Ras Mohammed National Park.

Captain Mohammed and Tony on the fly deck

Life on board the boat had a simple rhythm: dive, eat, sleep, repeat. During surface intervals the crew moved to new sites, and we either dived directly from the liveaboard or were transported short distances (in full kit) on Zodiacs – rubber ducks like the ones we use in Cape Town. During the time we were away, we had the opportunity to do 21 dives of which four were night dives. The diving was spread over six days. We skipped a couple of dives for various reasons including tiredness and illness, but overall managed to do a lot of diving in a short space of time. The warm water and helpfulness of the crew meant that it wasn’t nearly as physically taxing as you’d imagine. We used Nitrox throughout, not so much because we were doing particularly deep dives and needed the extra time (though it certainly helped), but for overall health reasons and to minimise fatigue.

Most of the time we were within sight of land. The landscape is mainly desert, with spectacular sunrises and sunsets. The reefs rise to within a few feet of the surface, and are clearly visible from the boat when it isn’t moving. Navigation in the Red Sea must be very tricky for the inexperienced, however. The number of spectacular wrecks is testament to this!

The day we arrived in Egypt and the day of our departure were mostly spent at the Marriott Hotel in Hurghada, waiting to board our vessel (the first day) and the plane (the last day). We lounged by the pool and checked out the private beach there, and felt very relaxed.

Prior to the trip we had some (understandable) concerns regarding the safety of travelling through Egypt to get to the liveaboard, but we kept tabs on the travel advice provided by the Foreign and Commonwealth Office of the UK. Since we would merely be in transit through Cairo airport, and would not actually be sleeping a single night on land, we were happy to go ahead with the trip. The Red Sea coastal area has been extremely calm throughout the recent unrest, and, as it derives 95% of its revenue from tourism, the locals have been keen to keep it that way.

The beach at the Marriott Hotel in Hurghada

We took a lot of photo and video on the trip, and will be sorting through it and sharing it over the next couple of months. Watch this space!

(No) decompression diving

Tony has posted about decompression diving before, but it’s been on my mind a lot lately after the winter diving this year.

If you’ve done a recreational scuba diving course, like a PADI or Naui Open Water course, you’ve learned how to do “no decompression diving”. Your entire dive is structured so that, should the need arise, you could ascend directly to the surface (in other words, without having to do a safety stop or decompression stop on the way up) without undue risk of getting bent. This is why you learn how to use the dive tables or the dreadful eRDP, and why you have time limits depending on what depth you go to. This kind of diving is considered (and indeed, is) far less risky than “decompression diving”, which involves overstaying the limits prescribed by the dive tables combined with staged ascents. This means that solving a problem by surfacing is just not an option (unless you want to create a whole other problem for yourself).

Tony safety stopping at Tivoli Pinnacles

As a beginning diver, it’s often a moot point that you only have x minutes of bottom time at a given depth: your air consumption is usually so poor that the air is gone long before the bottom time is up! As you dive more and more, however, the time limits really come into play and you may find yourself ascending with lots of air to spare, but because your computer tells you it’s time to go.

Particularly on repetitive dives (I’m thinking of a day when I did three long dives to at least 20 metres, all before lunchtime) you’ll run the risk of going into deco (in other words, incurring a mandatory stop on the way up in order to get the nitrogen out of your body tissues). Diving on Nitrox can help a lot with this, and it’s healthier, but there may well be occasions when you do find yourself in deco even after just one long (or deep) dive.

The first time it happened to me I got a bit of a fright. I’d read my dive computer manual back to front and made sure I understood all the warnings and alarms, so I knew exactly what it was telling me, but I wasn’t happy. We ascended a bit, my computer went out of deco, and after my three minute safety stop it gave me the all-clear to ascend. I had an idea in my head that going into deco was REALLY BAD, and I confessed it shamefacedly to Tony on the boat afterwards. He wasn’t too fussed; and as Grant pointed out, “There are worse things than going into deco – like not doing your deco stops!”

A little reflection, however, convinced me that I hadn’t done anything wrong (except perhaps not forseeing that this was going to happen and mentioning it to my buddy, who happened to be Tony!). I’ve done over 150 dives in the two years I’ve been diving, my air consumption is excellent, and I’m very calm underwater. Tony and I know each other well enough that our underwater discussions can be quite detailed. I’ve since allowed myself to go into deco a few times, never more than a few minutes because I dive on a single 10 or 12 litre cylinder, and I’ve done the stops that my computer requests of me (usually only an extra 1-3 minutes plus a 3 minute safety stop). I can tell you that this can be a little boring, unless you have jellyfish and seals for company, or an entertaining dive buddy!

I am very, very glad that I have my own dive computer now, and make sure that I understand exactly what it’s telling me at each point in the dive. I’ve been on a deep dive, and two young divers who didn’t have computers spent the entire dive below me. I went into deco and got a one minute stop on the way up; they must have incurred a much longer obligation, but didn’t know about it because they didn’t have dive computers. If you’re at special risk of decompression sickness due to age, weight, fatigue or other considerations, a dive computer is even more important. Small changes in depth can make large changes in the amount of bottom time you have remaining, and unless you are glued to your buddy’s side all the time, relying on their computer to keep you safe is risky.

Handy hints: Draining your drysuit

A drysuit is designed to ensure you remain dry whilst underwater. Personally I have had some experience with this but recently having had it repaired by Grant it is no longer refered to as a dampsuit but rather as the best piece of dive gear I have ever bought.

Anyway here is a handy hint for a drysuit that is wet inside after the first of a series of repetitive dives. After dive one, prior to dive two, find a sloped surface, and lie with your head facing down the slope. Allow the water to pool at your neck and cuff seals and then stick a finger in there to release the water. Simple.

Here is Peter Southwood doing just that at Miller’s Point… Maximum allowed drain time here is 20 minutes, according to the sign!

One can only do this for 20 minutes at a time

(Be prepared for a few comments such as what happened? Is he okay? Is he nuts? Is he dead?)

Handy hints: Sleeping on the beach

Clare is never one to miss an opportunity for a nap. She sat out one of the dives in Sodwana early one morning (she’s not a morning person and besides we’d had some hectic days prior to that). It was overcast but there was a glare from the sand, sea and clouds, and there was a slight breeze that made the air a little cold.

When we returned to the gazebo we found a jumbled pile of clothing, towels, sarongs, hats and neoprene. Somewhere under there was Clare, looking like a hobo and just waking from a nice little sleep.