FAQ: What can I expect on a deep dive?

I was very nervous before my first deep dive. It actually took a few deep dives before I was comfortable with them, and now I even look forward to them. Mental preparation for deep dives is something you might need to work on – it’s easy for one’s imagination to run wild when it’s an unfamiliar skill.

If you haven’t done a deep dive before, there are some things that you might want to know in advance:

  1. There will be a boat ride. You’ll roll over the side of the boat on the skipper’s count, along with the other divers. Don’t roll over late – rather stay on the boat and let the skipper drop you again when everyone has moved clear. If you land on another diver it’s a good way to ensure you won’t get invited for any more boat dives!
  2. You will probably descend on a shot line. This is a weighted line with a buoy on the end, and the skipper will drop it close to the  reef or wreck you plan to explore. You’ll use the line to make sure that you find your dive site – you’ll be descending through a large water column, and a current can easily carry you away from your destination. Circle the shot line gently with two fingers and use it as a guide while you descend. DO NOT grip it like a monkey!
  3. If you’re diving in Cape Town, it’ll be cold. And it’ll get colder the deeper you go. It might even be dark, too. The first 10-15 metres of water may be very murky and green, but down below that the visibility will probably improve, even if it’s dark.
  4. You will feel stupid. At about 25 metres, nitrogen narcosis becomes a noticeable issue. If you feel weird, ascend a bit, wait for it to dissipate, and then resume your descent – SLOWLY. But even if you don’t get it severely, your mental abilities WILL be limited. This is a fact of deep diving on air. You might find your field of vision narrows a bit, that you obsess over things, or that you are very conscious of only being able to do one thing at a time. All this means you need to take extra care, and don’t be reckless. Stay close to your buddy and watch each other carefully.
  5. You will feel heavy at the bottom – no matter how much or how little weight you are wearing. Don’t wait until you’re at 30 metres to start inflating your BCD. Stop at 10 metres, slow your ascent, and inflate your BCD slowly as you continue going down. This way you won’t rocket into the sand at the bottom (assuming there IS a bottom within the range of scuba – not the case if you’re diving a wall) like a cannonball, the chances of severe nitrogen narcosis are minimised, and you can be in control of your buoyancy all the way down.
  6. Colours will be dim and greyish. Take a torch – you may not think it’ll make a difference, but even at 20 metres the reds and oranges are significantly diminished and by 30 metres you just won’t see them at all without artificial light. One of the joys of deep diving is illuminating a very ordinary object and seeing the colours pop out at you.
  7. Swimming will be more of an effort than usual. The water will feel a bit like molasses – thick and viscous. You’re under tremendous pressure, and you simply won’t be able to dart around like a mosquito. Take it slow, don’t over-exert, and move at the speed of natural creatures.
  8. The dive will be short. This is for two reasons: first, you will use your air up very quickly at depth. If it is your first deep dive, this will be especially true – you’ll be nervous, or excited, and you won’t have the experience that enables you to reduce your air consumption. Second, your no-decompression time decreases the deeper you go. So even if you have lots of air, you will only be able to spend 20 minutes or so at the bottom before you have to ascend. If you can’t remember what no-decompression time is, it’s time to revise your dive tables!
  9. You will do a safety stop. Don’t be slack with this – it is absolutely vital. You’ll ascend slowly, maybe stop at 10 or 15 metres for a little bit, and then do a safety stop of at LEAST 3 minutes at 5 metres. Your cylinder will be quite empty, so you’ll be buoyant. Make sure that you control your buoyancy very carefully. Watch the Divemaster, your computer, or the reel on the DM’s buoy line (he may let it hang in the water next to him) to ensure that you stay at a constant depth. Your depth gauge will respond slowly to changes in depth, so it’s not hugely reliable at this stage of the dive.
  10. You might deploy a surface marker buoy (SMB). Your instructor may get you to do this yourself, for practice. An SMB (or as I like to call it, a safety sausage!) is a long tube on a line, usually orange or yellow, that you inflate with air from your octo (NOT your regulator). One end is closed (the top) and one end is open for you to put your octo into and press the purge button to fill it with air. It stands up straight in the water, and warns passing boats that there are divers about to surface. It also shows the skipper of your boat where you are, so that he can be nearby to fetch you. When inflating the SMB, hold onto the line attached to it – not the tube itself, or you might be pulled out of the water with it when you inflate it. Don’t fill it to capacity if you’re still at the safety stop – just a couple of purges of your octo will be enough. As it ascends the air will expand and when it reaches the surface the SMB will be sufficiently inflated to stand vertically out of the water.
    Gerard demonstrates correct safety stop technique in Sodwana
    Gerard demonstrates correct safety stop technique in Sodwana

    In the photo above, note how Gerard is watching his dive computer for depth and while it counts down his safety stop, hanging onto his SMB while he waits to ascend.

  11. There should be a hang tank for you to breathe off at the safety stop. A hang tank is a spare cylinder of air, with several regulators attached. It allows you to complete your safety stop without worrying about being low on air, if that’s the case. It also provides a useful reference for keeping yourself at a constant depth while you’re degassing!

    Divers breathing from a hang tank in Smitswinkel Bay
    Divers breathing from a hang tank in Smitswinkel Bay

Newsletter: Dive report and southeaster

Hi everyone

I hope you have had a great Christmas and hopefully a break from the office. Fortunately my ”office” has been busy and I don’t relish a break from it. I know there are many of you chomping at the bit to dive and finish your courses but the southeaster has been howling non-stop since Saturday and the sea looks a little like pea soup. I hope it dies down soon so we can all get back in the water. Sunday’s early boat dives were also cancelled due to an unforseen breakage on the boat.

Strawberry sea anemones and a pink urchin on the Romelia
Strawberry sea anemones and a pink urchin on the Romelia

I spent Friday in the Newlands swimming pool with a family of five, the youngest being 9 years old. Abby was doing a program called Seal Team. It is unbelievably rewarding teach such young kids to dive and her older sister and brother, mom and dad took longer to get comfortable than she did. I had hoops in the water and by the second session in the water her buoyancy was perfect and she swam through the hoops with a big smile on her face.

Gas flame nudibranch on the Romelia
Gas flame nudibranch on the Romelia

I am going to plan a day in the diving pool at Newlands, it’s five meters deep and a perfect place to hone bouyancy skills, trim your gear and cull some of the weight from your heavy weight belts. Its also a wonderful place to test and get acquainted with all the amazing dive gear you got for Christmas…

Divers explore a wall
Divers explore a wall

Early January I will be starting a Wreck specialty and plan to include penetration into the Aster, lying in Hout Bay on the sand at 25 metres. I am also going to run a Nitrox and Deep specialty so if going to 40 metres is on your to do list don’t miss this (I hope you got a torch for Christmas)!

We recently dived the wreck of the Romelia (pictures courtesy of Clare). The visibility was not great but the colours and sea life were stunning.

Sea life on the side of the Romelia (encrusted with orange coraline algae)
Sea life on the side of the Romelia (encrusted with orange coraline algae)

There is an amazing contrast between the life, colour and water temperature between the Atlantic sites and the False Bay sites. I tend to favor the False Bay coast as the water is warmer but every time I dive the Atlantic I am astounded by the clarity of the water. On our last wreck dives, the Maori and the BOS 400 we had 20 plus metres visibility.

Hottentot in the red bait zone above the Romelia
Hottentot in the red bait zone above the Romelia


Learn to Dive Today logoTony Lindeque
076 817 1099
Diving is addictive!

<strong><a href=”https://www.learntodivetoday.co.za/blog/wp-content/uploads/2010/09/small-colour-e1284626229322.jpg”><img class=”alignleft size-full wp-image-486″ title=”Learn to Dive Today logo” src=”https://www.learntodivetoday.co.za/blog/wp-content/uploads/2010/09/small-colour-e1284626229322.jpg” alt=”Learn to Dive Today logo” width=”73″ height=”67″ /></a>Tony Lindeque</strong>
076 817 1099
<a href=”http://www.learntodivetoday.co.za” target=”_blank”>www.learntodivetoday.co.za</a>
<a href=”https://www.learntodivetoday.co.za/blog” target=”_self”>www.learntodivetoday.co.za/blog</a>
<em>Diving is addictive!</em>

When you shouldn’t dive

Ear or sinus problems

If your nose and/or ears are blocked, stay dry until they’re cleared. If you dive with a blocked nose, you can potentially end your diving career altogether, as well as causing yourself a painful injury.

Alcohol and drugs

If you drank too much within the last 24 hours, or took recreational drugs, stay out of the water unless you have a death wish. How you feel is often no indication of how substance abuse has affected your reflexes and judgment.

Prescription drugs such as painkillers and sinus medication may also impair your concentration and make you unfit to dive. Also, be very careful of diving after taking medication that you’ve never used before.


If you are feeling very nervous about the dive, I’d think very, very carefully about whether you want to go ahead with it. Try and identify what’s making you anxious. Are you planning a dive that is beyond your capabilities? Do you trust your buddy? Are you auditioning for Jackass? If you take risks, you will come short.

Your buddy

Do you know your buddy? Are you comfortable with the diving practices of the group you’re joining? If you’re with an instructor, you are within your rights to ask to see his certification card. Trust is vital when you are scuba diving, and it’s better to call off a dive than to go out with a group or individual whose diving practices are suspect. Stranger danger doesn’t only apply to six year olds.

Pressure from others

Do YOU want to do this dive? Or does your husband, wife, boyfriend, girlfriend, or best friend want you to do it more than you yourself want to? Analyse your reasons for getting in the water very carefully. If YOU don’t want to, it’s better to say no than to do something that you are not comfortable with.

Your kit

You need to check your kit yourself, BEFORE you get in the water. Things to check include:

  • that your air smells clean and fresh, and has no discernible taste
  • that your cylinder has been filled – you have sufficient air to complete the dive
  • that you can inflate and deflate your BCD
  • that your torch batteries are charged, if applicable
  • what the Nitrox mix is, if applicable
  • that your dive computer is set to the correct Nitrox mix, if applicable, so it gives you the correct bottom time and maximum depth
  • you have the correct exposure protection (diving in freezing water with a thin wetsuit is asking for trouble!)

Travel plans

Are you taking a flight within 12-24 hours of diving?

Night dive at Long Beach (2010.06.05)

Here’s a video clip from a night dive we did in June this year at Long Beach. Look out for the box jelly with one tentacle, a klipfish, the beaked sandfish digging themselves into the sand, two warty pleurobranchs, an octopus hiding under a piece of plywood, a cuttlefish under the wreck, a two tone fingerfin, and a little jutjaw (we think).


This is an early night effort taken on my Sea&Sea camera with torches instead of a strobe. The resulting hotspots are eliminated when using the Bonica Snapper, provided the light is positioned appropriately.

Pictures of the Bonica Snapper

Following on from my review of the Bonica Snapper underwater video camera, here are a few pictures to show the camera, the housing and the component parts.

Camera inside silicone skin
Camera inside silicone skin
Open housing with the orange filter attached
Open housing with the orange filter attached
Top view of the sealed housing, filter and wide angle lens fitting
Top view of the sealed housing, filter and wide angle lens fitting
Applying the wide angle lens
Applying the wide angle lens
Cover I constructed to reduce glare on the viewfinder
Cover I constructed to reduce glare on the viewfinder
Bonica strobe - front view
Bonica strobe - front view
Side view of the Bonica strobe
Side view of the Bonica strobe showing dimmer switch

Night Diving Specialty… Completed!

On Saturday I did the final dive of my Night Diving specialty course, and Kate did the first one of hers. We went to Long Beach, did a dangerous surf entry through the 3 inch high waves, and proceded to do some night time navigation.

The goal was for us to make our way out to the yellow buoy, and then swim back on a slightly different heading. In retrospect it was a tough ask, because the buoy is attached to the sea floor by a chain. Unless we had been pinpoint accurate, we’d never have seen it (and indeed we didn’t) even if we were a few metres away.

Kate and I getting our bearings on the beach
Kate and I getting our bearings on the beach. To infinity and beyond!

Night navigation SUCKS. I did not enjoy it at all, but feel rather proud of myself and Kate for our efforts. We did spend two intervals on the surface arguing about which heading to take, and the second time we surfaced for a look-around, we lost the buoy. Detective Kate deduced that it was behind the yacht on our right (yes, we were THAT far out).

Juggling compass, torch, camera (have not figured out night-time photography yet, so my pictures are like something out of the Blair Witch Project) and dive computer left me feeling as though I did not have enough arms. Some kind of wrist-strap that will make the torch an extension of my arm is definitely in order. The fact remains, however, that night diving is awesome fun… But this expedition did persuade me that it’s more fun when you know where you’re going!

Wreck penetration

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

Wreck penetration
Wreck penetration

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.

Wreck penetration
Take care not to swim into overhead environments without a reel, line and a 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.

Wreck penetration
Orient yourself using daylight when penetrating a wreck

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.

What’s in my dive bag

I have travelled around a bit and dived in some very remote places, miles from a dive shop. Over the years I have collected an array of gadgets. Dive shops are full of shiny things you had no idea you needed until you saw them for the first time. There are some very important basic add-ons to your standard battle dress, things that no self respecting diver would dive without, and then there is a range of nice to have items, and then the usual ”not required but I have it anyway” list.

Must have items

DAN medical insurance

DAN tag and spare O ring
DAN tag and spare O ring hidden on the hose protector

Attach the red DAN tag to your BCD or regulator so that in an emergency your rescuer can get you the help you need. DAN will cover you for the expensive possibility that you need recompression in a chamber if you have a suspected case of the bends, as well as for any other diving-related medical emergency treatment that your medical aid refuses to cover. An ordinary medical aid will probably not pay for recompression treatment. Visit the DAN (Divers’ Alert Network) website for details.

A surface marker buoy (SMB)

Reels and surface marker buoy (SMB)
Different sized reels and surface marker buoys (SMB)

Reels come in all shapes and sizes, with thumb reels, small reels and large reels. I use a small reel on shallow dives and a large reel on deeper dives.

In a rough sea or poor conditions an SMB makes you far easier to see than a head and shoulders dressed in black bobbing on the surface. You should not dive without one in Cape Town.

Dive Knife

This should be big enough to cut fishing line in case you or your buddy get tangled up (or need to rescue something or someone). Not to be used for stabbing sharks, or your dive buddy! You can buy huge dagger-type knife, but it may be an overkill, unless you have aspirations to be a pirate. Small cutting tools that you can wear on your gear are more practical.

Dive torches and a handy-sized knife
Dive torches and a handy-sized knife


This should ideally be small enough to keep in a pocket, unless you’re doing a night dive and need some serious light.

You don’t necessarily need a torch only on night dives – you may want to see something that’s hiding in a dark environment, or it might be an overcast day. On a deep dive, a torch is essential because the colours can look so washed out.


Knowing where you are going or where you came from is quite useful at the bottom, as on land. Enough said.

Dive compass styles
Dive compass styles

Dive computer

There are many different styles. Some can be worn as everyday watches, and others are only for diving.  Here are three variations:

Dive computers
Dive computers in three styles. The two on the left can be worn as dress watches.

Signalling devices

Signalling devices
Signalling devices, from left to right: shaker, air horn, whistle.

A whistle is required for the surface (many BCDs come with one attached – you may not have noticed it as it might be helpfully coloured black to match the inflator hose). An air horn works above and below the surface and a shaker works best underwater but can be used on the surface.

You can also use a hard object like a dive knife to rap on your cylinder, which will be audible to your buddy underwater, but don’t necessarily rely on having something suitable to hand – or having the presence of mind to look for it – in an emergency.


Dive slates
Dive slates: the one on the left is useful for compass navigation. The one on the right is a wrist slate (note the mysterious arm it’s mounted on).

Underwater slates come in all shapes and sizes. A wrist slate can be pleasant as it’s always close by but easily accessible. Flat slates must be clipped to a D ring – and don’t forget to secure your pencil!

DIN adaptor and O rings

DIN adaptor and O rings
DIN adaptor and O rings. The little blue cylinder clips to your keychain and can be used to store spare O rings.

Some resorts only have old style aluminum cylinders and if you have a DIN regulator they don’t fit as there is no removable insert. Here you will require a DIN adaptor so make sure you enquire as to type of cylinders available when you book your vacation, if you intend using your personal regulator.

It’s also handy to have an allen key to remove the inserts if you routinely dive with your own regulator.

Nice to have items

Clipping things to your BCD is a surefire way to ensure they do not become lost property. There are many different types of clips available. No matter what I take underwater, it will always have a clip attached that will enable me to clip it to my BCD if I suddenly need both hands for something.

Cyalumes, mouthpiece and spare finstrap
Cyalumes, mouthpiece, clip and spare finstrap

Spare mask and fin straps are nice to have particularly if you have a odd type of fin or mask.

Spare octo clips are handy as well as a few cyalumes in the event of an impromptu night dive.

If you travel to remote locations in your own 4WD you may find yourself with a puncture, so a tyre inflator is a handy addition to the dive bag. Deep divers know the benefits of Nitrox and the risks involved in diving with the wrong mix so a Nitrox analyser helps you to double check the reading reached by the dive store. If you find your reg breathes with difficulty, or you second stages constantly leak, checking the system pressure with your own handy pressure gauge will give you an indication as to the root of the problem.

Nitrox analyser and pressure gauge
Nitrox analyser (top) and pressure gauge

Scuba gear: to buy, or not to buy?

Imagine this scenario

You are in the middle of your Open Water course. There is possibly some pressure from your instructor/dive centre to make a scuba gear purchase. It is time to stop and think.

This will not make me very popular in the dive industry…  But I do not recommend you buy your first set of dive gear without a fair amount of research. Sure, this can easily be done on the web or in one day by visiting a few dive centers, but the reality of the matter is you are new to the sport, you have yet to build a vast data bank in your head of the multitude of options available, you are impressed by your instructor’s opinion, and are swayed into buying the gear. A month later you decide diving is not for you, sky diving is the next option and you try and offload the gear with a ”hardly used dive gear” advert… You are going to lose money.

Wetsuit only worn once
Don't let this be you!

But let’s be positive and say that you have decided that diving is the best thing you can do clothed. Some time has passed. You are done with the Adventures in Diving, have at least 10 dives in your dive log and want to dive the world.

You have booked your flights to the Red Sea and are starting to pack, thrilled with the idea of arriving at the dive centre with all of your own gear looking like a hard core diver. You even have your own heavy duty dive bag with wheels,  handles and pockets galore.

You are now faced with a dilemma…

That fancy dive bag, the wheeled one with pockets, weighs 6 kgs empty. That won’t work, so you haul out the old lightweight bag you used on your previous travels.

The water temperature where you are going is 30 degrees, ouch, that 7mm two piece wetsuit won’t work there, so you decide to leave it at home and rent one.  You discover your fins weigh a ton and are so long they wont fit in the old travel bag you are now using for weight saving, your very expensive BCD with 6 pockets, a back plate and 8 D-rings is also far too heavy… and to top it all your top of the range regulator is way too expensive for check in luggage and way too heavy for hand luggage. You decide to leave the whole lot at home and rent the hard and soft gear at your destination.

Ah, that ”brightest dive light in the world” that you bought, weighing in at 3kgs, is a bit too heavy so you decide to leave it at home too, and rent a light.

Dive lights
You can get dive lights in a wide variety of strengths, shapes, weights and profiles. Do your research!

So you arrive at your destination, rent everything you need and have a wonderful trip. You cram as many dives possible into every day and head home feeling wonderful. On the way home you reminisce on the dives, replaying them in your mind over and over again (this always happens when you are a dive junkie, trust me).

  • ”That lightweight BCD I used with rear inflation is much more comfortable than my side inflation one… Hmm…”
  • ”The rental dive torch was small, light and compact, and fitted easily into the one tiny pocket on the BCD, I wonder why I thought I need a BCD with 6 pockets? Hmm…”
  • ”It was real easy getting into the rental wetsuit with a zip in front, why does my wetsuit not have that? Hmm…”
  • “Those short fins were so light and never made my legs tired – why do my fins feel so heavy?… Hmm!”
  • ”That tiny mask they gave me was a breeze to clear, but mine is so big it takes several breaths to empty. Hmm…”

When you arrive home you re-evaluate you dive gear. It’s not junk, by no means, but not quite what you have found to be the best option. So you embark on a long, slow, deliberate road to replace these items with items in the style you have found to be ”your comfort zone”.

What to do?

This point – of having well-formed preferences for different types of gear – is only reached once you have dived for a while, once you have done 10-20 dives. There is no way you are able to reach this point half way into your Open Water course.

Many people will advocate that in the interest of health and hygiene you purchase your own soft gear, wetsuit, booties, fins, mask and snorkel, and some dive centres will only conduct your training if you make this purchase.

In all fairness to the dive centre, sales person, or your instructor, they will give you sound advice, and no manufacturer makes ”junk” in this industry. But the advice will be based on their own style, based on what they have available in their store and they will seldom recommend you shop around. It would be foolish to do so, but before you rush out and buy, try different configurations, rent different gear and decide what works for you.

For some general advice about buying gear, you can visit my follow-up posts on hard (BCD, regulator, cylinder) and soft (wetsuit, mask, fins, booties) gear.

Night Diving as a Specialty or a fun dive

Tony and I do night dives quite often. We love it – there are creatures that only come out at night, and there’s something very exciting about going somewhere familiar and seeing how different it looks at night. We’ve seen something new on every night dive we’ve done (latest: white sea catfish at Long Beach). Besides, I LOVE cyalumes (for the uninitiated, those are the awesome little light sticks that you snap to release a chemical and then they start glowing) and all things glow in the dark.

I admit that I found my first night dive a little bit scary, and I still find I have to be more deliberate about relaxing in the water and not letting my imagination run wild. But it’s a very good discipline, forcing yourself to breathe deeply and be calm, and very quickly you get distracted by all the creatures that are either attracted to or hypnotised by your torch.

A lot of fish will swim right up to your torch, giving excellent photographic opportunities and time to examine them in detail. I specially like the beaked sandfish – they only come out at night (when I dive Long Beach during the day, I always wonder where they are). They’re long, thin, shiny, cream-coloured fish with translucent fins like dragon fly wings, and they use their pointy noses to dig themselves into the sand when they get a fright. But most of the time they gather together in little groups, milling about langurously on the sand. They love to check out torches and are not shy unless you make sudden moves or try to touch one.

I’m busy doing the PADI Night Diver Specialty – since we do so many night dives, and since I’m hungry to learn more at the moment, it seemed like a good idea. It’s not a demanding course at all, but I’m enjoying it. The manual covers night diving techniques in a lot of detail, and has a very useful section on choosing a dive light, and the relative advantages of different types of light and batteries. Most of it seems to be common sense, like remembering not to shine your light in people’s eyes, not going into any overhead environments (because there’s no daylight for orienting yourself) and making sure you have a backup light. However, it’s the kind of common sense that one needs to be reminded of or have specifically pointed out – I would never have thought about the danger of going into caves or penetrating wrecks at night, and would probably have gotten myself into trouble without giving it a second thought.

The practical section of the course involves three dives. There are a couple of navigation tasks, and on one of the dives you have to sit on the bottom for three minutes with the lights off. It’s surprising how light it is underwater at night. We did a night dive at Long Beach on Saturday, and even though there was cloud covering the moon, the ambient light underwater from our cyalumes and from the city lights was not inconsiderable.

If you enjoy night diving, or want to challenge yourself with something new, different and unusual, this is a really cool specialty to try. You can also do a night dive as a fun dive with an Open Water Qualification, or as an Adventure dive towards your Advanced Open Water diver qualification.