Purchasing your first dive lights

Most recreational scuba divers purchase their first dive lights in preparation for an advanced class. In most big dive training agencies, the advanced course is the second course divers take, and prepares them for diving deeper than 60 feet (up to 120 feet) and diving at night, along with other additional skills that vary from course to course. Although it may be possible to rent the lights you need for these dives, many divers take this opportunity to get their own set. As always, it REALLY pays to do a little homework: the bang for your buck from product to product and from dealer to dealer varies ENORMOUSLY with dive lights, as with all scuba gear.

WHAT YOU NEED: To safely do recreational night diving, you need 3 new pieces of gear: two dive lights, and a marker light or more commonly a glow-stick. Your primary dive light is what you’ll mainly be using to get around underwater in the dark, and your secondary dive light is a backup in case anything happens to your primary, and is non-optional. A glow-stick or marker light, often attached to your tank valve, (or duct-taped to your snorkel for glow-sticks), allows your dive buddy to see you underwater even when your primary dive light is pointed away from them, and these markers really come in handy, especially on night dives where the visibility is less than ideal.

TYPES OF DIVE LIGHTS: Portable light technology is rapidly being transformed by new very powerful LEDs, and in the near future LEDs will almost certainly offer the best bang for your buck. Take a look at websites like zbattery.com for the cheap, high-powered LED homebrew parts that will be standard in dive lights a couple of years from now, if you’re curious. As of right now (August 2008), however, it’s still a toss-up between LED’s and traditional xenon or halogen bulbs. Finally, HID (high-intensity discharge) lights have long been a staple of the cave and tech-diving communities. They’re insanely bright, but they’re normally many hundreds of dollars for even a small one, so we’ll only discuss one surprisingly inexpensive model in this roundup.

IT’S ALL ABOUT THE LUMENS (sort of): Total light output is measured in lumens, and manufacturer’s websites will include the output in lumens for all of their models. There are some other factors that affect how bright a dive light will seem underwater- specifically, color of the light. “Whiter” lights which are further toward the blue end of the spectrum will cut through the water better than “yellower” lights whose output is further toward the red end of the spectrum. Sunlight behaves the same way, which is why at depth during the day, everything appears blue: the blue light is going farther down than the red. In general, HID and most LED lights will be whiter than xenon or halogen lights. Luckily, within the lower price range I’m suggesting for an entry level dive light, I think this more complicated and harder to quantify color issue can largely be glossed over, in favor of simply looking at total output in lumens.

THE SUMMARY: Below is a table of several commonly available primary and backup dive lights, with lumens, best online price, and lumens per dollar shown (click on it for a larger version). Obscure and hard to find manufacturers, and models that were clearly inferior to others already mentioned at the same size and price point, were excluded for simplicity, as were any models I couldn’t readily find online pricing or lumen data for. For pricing, these are online prices. Expect to pay somewhat more at a great reputable local dive shop, for the luxury of getting to try before you buy. However, keep these numbers in mind so you don’t get scammed for two or even three times these prices by less scrupulous local shops, which unfortunately aren’t in short supply.

The very clear winner here for lumens per dollar is the Pelican NEMO 8C. There are only two brighter lights in our roundup, and they cost roughly 5 or 6 times as much as the NEMO. The best lumens per dollar for a backup light is the Princeton Tec Torrent Xenon, not because of a low price but because it’s a very bright yet small backup. In fact, it’s advertised as a compact primary, but I think divers would only consider it as such if they weren’t aware of the availability of the MUCH brighter NEMO 8C for the same price.

Pelican NEMO 8C

Pelican NEMO 8C

PRIMARY RECOMMENDATION: The Pelican NEMO 8C is the very clear best bargain. It’s worth adding that although all of these manufacturers have a warranty against defects, Pelican’s long-proven policy for everything they sell is the simple and to the point “You break it, we replace it, forever”, which is about as good as you’re going to get, and I can add (EDIT) that I’ve personally contacted Pelican customer service before with a technical question and found them to be really top notch.  If you really need something a lot brighter, and/or price isn’t as big a factor, take a look at the UK Light Cannon HID or UK C8 eLED Plus. I’ve dived my NEMO alongside a buddy who was using a Light Cannon HID, and the difference was noticeable- the HID is REALLY bright, although you pay a pretty penny for it.  Both the UK Light Cannon HID and the UK C8 eLED have an available lantern or pistol grip, so be sure you’re getting the option you want (the NEMO is only available in pistol-grip), and although the HID is brighter than the LED, HID replacement bulbs cost around $80 or more (LEDs should last forever if used correctly), so factor this in if you’re going to splurge for some extra brightness but you’re on the fence about the Light Cannon vs. the C8 eLED.

Princeton Tec Torrent Xenon

Princeton Tec Torrent Xenon

SECONDARY RECOMMENDATION: Princeton Tec Torrent Xenon. If the only thing you’ll ever use your backup light for is in case your primary fails, get the Pelican MityLite 4AA or the UK Mini Q40, and save some money. However, my favorite use for my backup light is as a “BC Light”, which I always keep in the pocket of my BC, so that I can peer under ledges and into dark areas during daytime dives, and even hold clumsily as a poor man’s camera light when taking underwater digital photos. For these addtional uses, I find a smaller backup-only light like the Pelican MityLite 4AA or the UK Mini Q40 to be a little on the dim side, so I was happy to find out about recently introduced Princeton Tec Torrent Xenon (now on its way) while preparing this review. UPDATE: I’ve replaced my Torrent Xenon with the newer, brighter Torrent LED which I love even more.

Princeton Tec Eco Flare

Princeton Tec Eco Flare

MARKER LIGHT: It only takes about 5 night dives to pay for a marker light vs. glow-sticks, not to mention getting to feel better about using a non-disposable alternative. Marker Lights aren’t rated for lumen output (and don’t need to be), and there aren’t a million of them on the market. I’ll mention two, both from Princeton Tec: the Eco-Flare, $8.95 online, 2AAA, and the Sport Flare, $11.95 online, 2AA. I’d get the Eco-Flare if you can find it.

Tektite Mark III LED Strobe

Tektite Mark III LED Strobe

OTHER LIGHTS: Finally, for underwater navigation, underwater strobes are great. If you’re planning your own boat dives, clip a couple to the anchor line at two different depths, and for shore dives in poorly lit areas, fasten them to something on the shore so that they can be seen in a straight line with one another if you’re swimming toward your exit point. It’s no substitute for good navigation, but they can come in handy for some kinds of night diving. I DON’T recommend these as marker lights; they’re no good for your buddy’s night vision. They do have one other use, though: on drift dives where you’ll be carrying a safety sausage / surface signaling tube, if you have a strobe in your BC pocket you can place it inside the tube before inflation to make it easier to spot in overcast or twilight conditions. The Pelican 2130 is the best bargain – although these lights aren’t lumen rated, because of its red lens I’d suspect it could be significantly dimmer than the other two models, although for its price it’s nice to have a couple of spares around to clip to anchor lines etc. in a pinch, and the red lens might make it an acceptable buddy marker light, although I haven’t tried one in that role.  Look for the Pelican 2130 LED Mini Flasher for about $7, Tektite Mark III LED strobe for about $21, or the Princeton Tec Aqua Strobe for about $26.

A FINAL RECOMMENDATION: It’s tempting to order your dive lights in the “NINJA black” color option. I sometimes suspect that this color is available to boost dive light sales, because if you drop a black dive light and it isn’t turned on, or lands lens-down, that’s about that. Your first few night dives can be very task-loaded, much like your very first daytime dives, and it’s easier than you think to drop something in the shuffle. I REALLY recommend going with the fluorescent yellow high visibility color options on your dive lights (unless you’re actually a ninja).  If you already have a black model, (maybe even if you don’t), get some 3M reflective safety tape, available at auto parts stores for about $2, and wrap a couple of stripes of it around your light to make it easy to spot when your buddy’s light shines on it, at least.

WHAT DO I USE? The Pelican NEMO 8C fluorescent yellow primary (love it), Princeton Tec Torrent Xenon fluorescent yellow secondary. (UPDATE: replace with the newer brighter Princeton Tec Torrent LED). I also have a Princeton Tec Sport Flare (guess what color), but I’d have gone with the cheaper Eco Flare if I had seen one around when I bought my Sport Flare- they both work great.

No matter where you’ll be buying your gear, Remember to always do Google Products (Froogle) search and / or a pricegrabber.com search to get a rough idea of what a reasonable price is on items you’re considering, to avoid being scalped by any unscrupulous retailers.  There are many great reasons to purchase your gear locally if you can, and I encourage you to find a reputable local dealer when available, and to use them when they stock the items you want. However, although in-store advice is well worth a few extra bucks, there’s no excuse for going into a shop without knowing what the going internet rate on an item is.  To give you an idea of how much you can be ripped off by the wrong retailers, I frequently see people selling worn-out gear used online for a price they think is a great bargain (i.e. less than half of what they originally paid for it new) when in fact a knowledgeable shopper can find the same exact gear BRAND NEW for a lower price than they’re trying to sell it for used.

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Add a skill: Square Spiral Search

Sometime in your diving adventures, you’ll end up losing something underwater that you really don’t want to have to replace. Maybe it’s only a mask or a snorkel, or maybe it’s a wrist mounted computer that cost you a pretty penny. In a separate article, I’ll review how to make a better wrist mount to avoid losing your computer in the first place, (hint: checkout the commercial version of the solution here, and from there it’s pretty easy to imagine how to make your own if you’d rather) but for now let’s return to how to find something you’ve lost. If you have a good idea where you last saw the item, and you have a compass (which you really should), my favorite search pattern to try is the square spiral search, also called the expanding square search. Obviously, you need to have some familiarity with compass navigation to use this search pattern, although not much. If you’re a little rusty on compass navigation, check out my review.

Square Spiral

As illustrated in the figure above, the idea behind a square spiral search is straightforward: kick once, turn 90 degrees counterclockwise, repeat, kick twice, turn 90 degrees, repeat, kick three times, etc. In very good visibility or with a brightly colored lost object you may be tempted to add two kicks every two turns, or use really long / powerful kicks, but I don’t recommend it, for a couple of reasons. The first reason is that even in the best of situations, when you find what you were looking for, you’ll be amazed how often you almost missed it even when going very slowly and carefully- it may be partially buried in the sand, for example. The second reason is that you’ll be doing this with a buddy who has to keep up with you, possibly in poor visibility, as explained below.

BUDDY SYSTEM: As with most recreational diving, the buddy system is an important part of doing a square spiral search. Basically, it’s difficult to watch a compass and look for a dropped object at the same time. This is where teamwork comes in. In this search pattern, one buddy works full time on counting kicks, and navigating 90 degree turns using the compass. So this buddy would start where you believe you’ve dropped the item, point their compass along a heading of 0 degrees, and kick once. The second buddy would follow the first buddy, focusing carefully on the bottom, and keeping the first navigating buddy in the same spot in their peripheral vision as they follow along. Next, the navigating buddy would pause to let the searching buddy catch up, turn to a heading of 90 degrees, and make 1 kick. Next would be two kicks at a heading of 180, followed by 2 at 270, etc.

SLOW AND EASY: In decent conditions it may be tempting to skip the beginning, close-in part of the spiral, since you will be covering a small space and reviewing the same patch of bottom for the first couple of turns. Sticking with these beginning tight turns is actually a great idea, and here’s why: kicking past the same bottom features a few times at the beginning of the spiral allows the navigating buddy to gauge how wide a stretch of bottom can easily be seen at once from your height and with your visibility, for this search. This lets this buddy adjust the strength of their kicks, to be sure that on each leg of the spiral, you’re seeing overlapping swaths of the bottom and not skipping any regions by going too quickly. If the searching buddy needs to ask for a longer or (more likely) shorter kick to ensure this overlap as the search progresses, simple bigger/smaller hand gestures (placing the two hands palms facing, and either pushing them together or pulling them apart) can be used to communicate this information.

If you’re dealing with a rough bottom, as you search widens, you may find obstacles along the bottom. In great visibility you may just be able to work at a depth above all small bottom features, but if you must deviate around them, I like to do a full circuit of the base of the feature, spiral up it if it could be supporting your lost item, and then continue the search pattern on the far side of the obstacle as planned.

PROPER PREVIOUS PLANNING PREVENTS POOR PERFORMANCE: The law of the six P’s is as applicable here as it is everywhere else in diving. During a meltdown about the loss of your new $1000 wireless computer is not the best time for you and your buddy to practice your first attempt at a square spiral search. You’ll notice when you try it that it can be a bit task-loading at first, but that a little practice goes a long way, and once you’ve gotten the hang of it you’ll find it to be a piece of cake when a real situation arises. My advice is to get a 2 pound soft shot weight pouch, the small black (i.e. hard to spot) ones, and use it as your practice “lost item” in shallow water. Have a third buddy toss it and observe where it falls while your backs are turned, and then have this buddy point you in the general direction of where the item was “lost” so you can begin your search. Obviously, if there are any delicate corals, etc. below rather than sandy bottom, have the third buddy place it gently on the bottom instead and surface to tell you where to begin searching. If the vis and conditions are especially nice and you want to really test your new skills, you may want to try a penny instead, and/or try having your third buddy point you slightly off course so that you have to spiral out a bit to reach the place the item was dropped.

Finally, while you’re doing your search, you still need to be doing all the usual diving things like monitoring your remaining air and your depth. My method is, at every other corner, when you pause with your buddy to make the turn, take a look at your gauges or computer. By planning to check this more often than absolutely necessary, you leave yourself a margin of error in case you miss a check once in a while.

Once you’ve practice a couple of times in each of the two roles, you’ll have a new tool at your disposal the next time a piece of gear tries to escape into Davy Jones’ locker. Although the square spiral is my favorite for recovering dropped scuba gear, for other situations, there are other search patterns, (for example, the jackstay search), which we’ll cover in future articles.

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Basic Skills Review: Compass Navigation

Compass Navigation

Although most of us had an introduction to compass navigation underwater during our initial scuba certification course, chances are you made your first few holiday dives on a “follow the divemaster” dive plan which didn’t require a lot of self navigation. By the time you’re ready to take on more independent dive routes, you might be a little rusty. Fear not; compass navigation underwater is a piece of cake.

PARTS OF YOUR COMPASS

compassnavforblog4.jpg

To tell you how to get the most out of your compass, we’ll need to cover a little bit of compass jargon first. The part of your scuba compass that moves and always points north is called the card. It’s usually white, with N,S,E, and W indicated, and a beveled edge with a series of mysterious numbers on it (more very soon on these). Then there should be a movable ring around the edge of the compass, usually black, called the bezel. An orange line or double line across the top of the compass is called the lubber line, and finally, there should be a little window in the side of your compass, which I have named for today the side window. That’s it!

BELT AND SUSPENDERS

The way I like to explain scuba compasses is to say that there are two easy ways to use your compass, that actually work together, although either alone will do in a pinch. Sort of like belt or suspenders. First let’s talk belt, or side-window navigation.

BELT

sidewindow.jpg

Side-window navigation couldn’t be simpler. You point the lubber line on top of your compass at where you want to go, with the side window facing you, and note the number. (Notice that the edge of the card is beveled at 45 degrees – this is so you can see the numbers on the edge both from the top and through the side window). Now as long as you hold your compass flat in front of you with the lubber line pointing in the direction you’re swimming, you should always see the same number in your window as long as you’re going the right way. If you see a different number, turn until you see the same number. This trick is the reason that the side window is at the back (closer to you) end of the lubber line on your compass! It sounds too easy but that’s really it.

Here’s a way that I use this very simple trick all the time: on shore dives, before descending, I point my compass at where I’d like to get out and look in the little side window. As long as I check my compass every so often and make sure I’m seeing the same number in the side window, I’m always swimming in toward my exit point. You might think you could do this without your compass, but I frequently get to the bottom with my buddy and try to ‘guess’ which way it is to shore before looking back at my compass, and I’m often wrong.

The downside of the side window method is that you need to remember your number, or you’re in trouble. I’ve always been lucky with this, but you can imagine that if you make several different navigation dives in the same day, you might start to get them mixed up. This brings us to…

SUSPENDERS

bezel.jpg

Navigating with your bezel works essentially the same as using the side window, but your bezel remembers your number for you. All you do is, point the lubber line on top of your compass at where you want to go, and then wait until the card settles down and stops moving. Then turn your bezel until the double triangle on the edge of the bezel (the notch right by the number zero on the bezel) is bracketing the north arrow on the card. Now as long as you hold your compass flat in front of you with the lubber line pointing in the direction you’re swimming, you should always see the north arrow inside the notch, as long as you’re going the right way. If not, turn until you see the north arrow inside the notch. That’s it!

Of course, if you bump your bezel underwater and move it, you’re out of luck.

COMBINING

That’s why ideally, you should turn your bezel until the notch brackets the north arrow, AND remember the number in the side window. Notice that if you’ve adjusted the bezel correctly, the number in the side window is also the number directly across from you at the front end of the lubber line. In other words, you can imagine in the picture above that if I turned the bezel counterclockwise until the notch bracketed the north arrow, the 120 on the bezel would be at the far end of the lubber line. Notice that on the card, the number showing in the side window is 120. Yep, they always go together whenever the bezel is adjusted correctly. If you were holding this compass and swimming in the direction of the lubber line, you’d be on a heading of 120.

COMMUNICATING BY NUMB3RS

Now that you’re friends with your compass, there’s a lot you can do with it. A divemaster can tell you “head down the anchor line, and head out from there at 150 to reach the reef”. When you get to the bottom of the anchor line, you simply turn yourself until you see 150 in your side window, or turn your bezel until 150 on the bezel is at the far end of the lubber line, and turn yourself until the north arrow on the card is in the notch. Then away you go to the reef. Remember, both methods point you in the same direction! I like to set the bezel as a precaution, then swim by using the side window. You may find it easier to use the top down view of your compass to stay on course.

RECIPROCAL COURSES

That’s great to get you to the reef, but how do you get back? Easy! If you’re thinking in terms of the bezel, simply turn until the north arrow faces not to the notch, but to the single triangle that’s exactly across from the notch. Now you’re pointed back where you came. Done. If you’re using the side window, take a look at the top of your compass. Note the number directly across from the heading that you’ve been on. If you look at the picture above, you can see that the number directly across from 150 is 330. So if you keep 330 in your side window on the way back from the reef, you should be headed for the anchor line. Again both methods of thinking about it will point you the correct way back.

SOME PEOPLE ACTUALLY LIKE MATH

If you have another source of info about compasses, they will tell you to “Add 180, and if this number exceeds 360, then subtract 360” to find how to head back where you started, i.e. to plot a reciprocal course. This is in fact correct, and if it’s not obvious to you right away, you can convince yourself by staring at the top of your compass that if you use this formula on any number you’ll always get the number across from it. This is important for people who need very accurate numbers, closer together than the ones on your compass- for example they’re heading out at 243, and they need to know to return along 63. For the level of accuracy needed for a lot of recreational dive navigation, you could just head out at 240 and return at 60, which allows you to look at the top of your compass for the answer and skip the math. Similarly, right and left turns should be figured by adding or subtracting 90 from your heading (again subtracting 360 if the result is greater than 360), but if you use the numbers on the top of your compass, you can just peek to see the answer.

THE REAL TRICKS

Great job so far. Unfortunately, the really tricky part of using your compass isn’t learning what the numbers mean and how to adjust the bezel (Sorry). The most common mistakes are not holding your compass flat, and not actually swimming in the direction your lubber line is pointing.

The card in your compass is balanced on a pivot, and if the compass isn’t held completely horizontal, the card will brush against the clear top and get jammed so that it can’t rotate. If you aren’t sure, try jiggling the compass gently. If the card moves, it was probably stuck before you jiggled it, which means your compass wasn’t as horizontal as you’d hoped. For this reason also, avoid buying or renting compasses that have bubbles inside (they’re normally liquid filled with no bubbles), as bubbles can exacerbate the card-jamming problem and make your compass more finicky about how horizontal it needs to be.

Most people hold their compass in one hand or the other, and find themselves veering off in the opposite direction. That’s because they think they have the lubber line pointed directly ahead of them, when in fact it’s pointed slightly to one side. The best way to improve this is just to practice. Try different methods of holding your compass to see what works best for you. Waypoint navigation (outlined below) also helps.

WAYPOINT NAVIGATION

Now that you know how to compass navigate like a pro, does it mean you’ll have to spend all your dive time staring at your compass instead of the scenery? Of course not. The best way to get somewhere with your compass is to use waypoints. If you’re heading along 150, just hold up your compass and look at the 150 in the side window, then look directly past it to the farthest really distinct underwater landmark (a large and distinctive coral, for example). Now enjoy your dive as you make your way to the previously selected waypoint- feel free to veer a little left or right if there are things you’d like to investigate more closely or photograph, etc. When you reach your waypoint, simply start over and select a new, farther waypoint, until you reach your destination. This way you can check your compass sporadically but always stay on course.

LOGGING HEADINGS

When your divemaster told you earlier in our lesson to head out along 150 to reach the reef, you were being told a heading. Heading is the name for the number. This is great info to add to your dive log notes and include on any sketched dive site maps. A “Heading from mooring line to reef = 150” note will come in handy if you’re back at this site again. For example, all of my shore dive site maps contain a “heading to shore” note, which tells me the heading I should use to get from where I usually descend (wherever the interesting dive features are) to where I want to exit on the shore. It’s not perfect if I move far from my descent point during the dive, but even then, it’s much better than having no idea which direction the exit point is.

DEVIATION

Finally, it might not come up often, but it bears mentioning: large iron and steel objects (like shipwrecks) can influence the magnet in your compass, causing it to point in the wrong direction. This is called deviation. If you suspect this is happening, simply move away from the object several feet, say by ascending several feet above it, and the problem should correct itself.

Coming up soon, we’ll extend our navigation skills by talking about taking bearings at the surface, as well as natural navigation.

There are a lot of good deals out there on stand-alone compasses, and some people really like being able to keep their compass separate from their other gauges.  However, if you’re planning to buy your own regulator and gauges, or dive computer, soon, you may want to wait and save money by getting a set of gauges or a computer that has a compass already built in. I use a Tusa SCA-330 Platina compact 3 gauge console, which has a great built-in compass.

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Add a skill: Cave Diver Kick

In addition to the flutter kick that all scuba students focus most on in their certification class, there are a lot of other options: for example the frog kick and dolphin kick are a couple that may come in handy in particular situations. One that can be immediately useful to a lot of recreational divers, and that I personally get a lot of mileage out of in open water diving, is the bent-knee kick, or cave diving kick. At the level of precision needed to use it in recreational open water diving, this kick is very easy to learn. It’s essentially a flutter kick, but with both legs bent at the knees at around 90 degrees, so that the feet are held up above the body if you are horizontal in the water and facing downward. Cave divers include this kick in their repertoire because it can keep the feet away from the cave floor when silt is present, to avoid disturbing the silt and thus greatly (and dangerously!) lowering the visibility in the cave. (I should take this chance to note as an aside that cave diving itself can be very dangerous and potentially fatal for the untrained; feel free to steal this technique from the cave diving arsenal for use in your open water dives, but never enter overhead environments where your direct access to the water’s surface is restricted without further specialized training and certification.) When combined with good buoyancy control and trim, the cave diving kick can give you a little more latitude to get close to reefs, rocks, etc. with less chance of banging into anything.

Often one of the most fascinating ways to view a reef or kelp forest is at the ‘macro lens’ level, where all of the tiny organisms that cling to the rocks come into sharp focus, and many well-camouflaged animals can be suddenly revealed by the closer inspection. Although well-practiced buoyancy control and trim, combined with clipped away and streamlined hoses and gauges, may keep you from physically touching anything on the reef, you can still unknowingly blast small organisms such as nudibranchs and snails from their homes with the water movement caused by your fin kicks. I’ve often observed students meticulously and successfully avoid banging into a part of the reef, only to see overturned starfish in their wake, caused by their fin blasts. When you’re observing a reef that’s below you, using the cave diving kick helps to be sure you’re not doing any starfish overturning, and lets you enjoy more close up face time with nature without doing any harm.

TIPS: Although the technique is simple, there’s one hint that can help you master it much more quickly, that’s also true for trim adjustments: because your fins (and any hapless starfish victims of your fins) are typically behind you, you may not be able to see whether you’re positioning your feet just where you mean to, but your dive buddy can observe and tell right away if your cave diving kick needs more work. Take turns with a buddy observing one another’s cave kicks from behind, and debrief after the dive to help improve your technique for next time. Repeat as necessary. Finally, if you’re in a situation where you feel this technique will be helpful, an additional tweak to keep your fins further from what lies below you is to move your trim to a slightly head-down position, rather than horizontal. Here again, your dive buddy may be a better judge of your success than you while you’re still learning and practicing. Once you’ve mastered this technique, in calm water you’ll be better prepared to place your mask quite close to what you want to observe without causing small scale havoc on any of the wildlife behind or below you.

If you’ve found this tutorial helpful, please consider making a small donation! Thanks and happy diving!

Basic Skills Review: The Valsalva Maneuver

The Valsalva Maneuver, named after 17th century anatomist Antonio Maria Valsalva, is a method that can be used to equalize pressure in the ears during a scuba diving descent. First we’ll review how to do the Valsalva maneuver and how it works, and then talk about a couple of refinements and alternatives. Although all scuba students learn this maneuver in their intro course, Divers Alert Network reports that ear injuries still account for up to one third of all of their calls for medical advice. They also publish a brochure on avoiding ear and sinus injuries that’s available at many dive shops and via their website, for free.

The human ear is normally designed to respond to very rapid pressure vibrations by sensing the movement of the eardrum, enabling us to hear sounds. Slower and longer pressure changes, such as those caused by flying or diving, can bend the eardrum or even tear it if the pressure isn’t kept equal on each side of the membrane. This equalization is accomplished by movement of air through the narrow Eustachian tube (named after 16th century anatomist Eustachius – in case you hadn’t already guessed, the tradition in medicine is to name things not based on their function, but on their discoverer, much to the chagrin of med students). The Eustachian tube system is adapted to deal best with relatively slow pressure changes over several hours or more. When we speed things up by diving to depths greater than a couple of feet, the system can often use a little help from us. Luckily, the other end of your Eustachian tube ends inside your mouth (well, pharynx), and this is where the Valsalva maneuver comes in. By closing your lips and pinching your nose, then exhaling GENTLY, you can move air into your Eustachian tube, and equalize pressure on descent. Obviously, the Valsalva maneuver is for descending to higher pressures, not ascending to lower pressures.

TIPS: In general, Eustachian tubes can be finicky, and they should be treated gently. Always perform your first Valsalva maneuver at the surface, before beginning your descent.  NEVER exhale forcefully to perform a Valsalva maneuver; if you can’t clear your ears during descent, ascend to a shallower depth and try again, even if this eventually means ascending to the surface to solve the problem. This is because increased pressure which hasn’t been equalized can pinch the tubes shut, and ascending will help them re-open. Forcing your Valsalva may also irritate the Eustachian tubes and cause swelling, which can make subsequent equalization more difficult.

A couple of other tips can also open the Eustachian tubes if the basic Valsalva maneuver isn’t working; there’s no reason not to incorporate these extras every time if they work well for you. One is to tilt your head back, so that you’re looking up at the surface of the water. Because the Valsalva is performed on descent, divers commonly automatically look down to see where they’re headed, but tilting your head up when clearing your ears works best. On this note, if your dive buddy is having trouble equalizing, don’t descend below them- it makes them look down at you, which hampers their Valsalva maneuver, and also may make them feel pressured to keep up, when they should be ascending instead if they’re having any trouble. Finally, extending your lower jaw straight out into a sort of underbite can also help a lot for some people.

CONGESTION: Eustachian tubes have an additional function: draining fluids from the inside of the eardrum, particularly in the case of ear infection or head congestion. In these situations, your ability to clear your ears is compromised, and the most prudent course is to avoid diving with any ear infections or head colds. You may be tempted to plan or begin a dive in this condition, only to have things worsen just before or during the dive, potentially leading to an ear injury. Although you may hear divers mention that some decongestants such as pseudoephedrine (Sudafed, etc.) can help to open Eustachian tubes, and they’re used for this purpose in non-diving contexts, most dive training agencies and dive operators recommend against their use for this purpose when diving, in part because even if they are effective for you, short-acting medications may wear off during a dive, and leave you back in a bad situation. Again, the safest choice is to dive again another day rather than risk injury.

OTHER METHODS: Some divers find swallowing alone is enough to open their Eustachian tubes, or sealing their tongue against the roof of their mouth and exhaling, or even stretching their jaw in a chewing motion. These methods can be gentler when effective, but are harder to teach to new divers, and are more commonly used by flight attendants and pilots, who deal with much slower pressure changes than divers. If you’re able to clear your ears this way, in addition to being gentler, it has the advantage of leaving both hands free since you don’t have to pinch your nose.

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Choosing your starting gear – Part 3: Fins

Fins

FIT: When choosing fins for scuba, open-heeled fins, which have an open back covered by an adjustable strap, are the way to go. These fins are designed to be used with booties, giving you options for using them in different water temperatures, for shore dives, etc. As usual, fit is the most important consideration; any scuba fins (i.e. NOT swim fins or freediving fins) that fit you well will do a good job. When trying on fins, be sure to use booties similar to the ones you’ll be diving with, or bring your own booties. If you’re ever purchasing, borrowing, or renting fins sight unseen, the best place to go for sizing information is the manufacturer’s website; this will usually have an accurate sizing chart that recommends a fin size based on your shoe size.

TYPES OF FINS: Most recreational diving fins are essentially of two types: split fins and paddle fins. There are also a couple of other specialty types. In choosing between split fins and paddle fins, there are a few considerations. A 2005 summary review of fins, which only covers newer models, was done by Scuba Diving magazine, and rates both splits and paddles in several categories, some categories more subjective than others. Their favorite in this test was the Apollo Bio-Fin Pro this year, and it was also the favorite each year for the past 7 years. See also this vendor review about split fins. Their summary is, specific types of well-made splits seem to be more efficient when used correctly, as measured by lower diver air consumption, and higher speeds when swimming a course underwater with gear. For a different view based on a different set of tests, see this summary of an article from Underwater & Hyperbaric Medicine Journal. Although the wording of the summary is confusing, the gist is that in U&HMJ’s test, while some fins performed much better than others, there was little correlation between the performance and specific manufacturer ‘features’ and geegaws such as vents or longitudinal splits. Despite the other differences in results, this review nevertheless also rated the Apollo Bio-Fin Pro as their test favorite. In the end, extra efficiency may be important to you if you do a lot of shore diving with very long surface swims, for example. The most immediately obvious drawback with split fins is that splits as a rule cost more, because the technology is still under patent by a company called Nature’s Wing, and for leisurely recreational diving, you may very well feel that the additional expense isn’t warranted. Also, while all split fins are based on the same patent, different manufacturers’ implementations can vary A LOT, so if you do decide on splits, you could end up paying extra, only to get less (maybe far less) than the full advantage, if you don’t shop around carefully. Finally, some feel that the more flexible split fins don’t support some types of small foot movements and maneuvering as well as paddles do (I disagree), and people who dive using thin strings to mark their return path, such as wreck divers and cave divers, have legitimate concerns that the strings may become entangled in the slot in the center of split fins.

Once again, some vendors will swear to you that a particular brand of fin is a million times better than anything else out there, and you’d be crazy to try anything else. Although of course every salesperson will have a favorite, as always, if they’re a little too insistent that there’s only one possible right answer, I’d advise taking this and any other advice from this salesperson with a grain of sea salt.

KICKING DIFFERENCES: To properly appreciate whichever fins you select, it’s important to know that the proper style for flutter kicking is slightly different for split fins and for paddle fins. In both cases, the trick is to use the large muscles up at your hips to move your entire legs, while keeping your knees relaxed, but at a relatively fixed angle. A common beginning mistake is to bend your knees with each kick as if pedaling a bicycle; this is bad, and you’ll practically stand still in the water no matter which fins you get. With split fins, your flutter kick should bring your feet about 18 inches apart on each kick, and with paddles more like 3 feet or so. Use these distances as starting guidelines, and when you get a chance to stretch out and swim in the water you’ll be able to fine tune for the stroke that propels you the best. If you’re a lap swimmer, most pools will let you take your scuba fins in and do a few laps to get the hang of your new fins, or brush up if you haven’t dived in a while.

BEGINNER TIPS: Many fins come with hard plastic supports inside the foot pocket, similar to shoe trees. These are only there to protect the fins during shipping; remove them when trying on fins, and discard them once you have your fins. This might seem obvious, but new divers frequently come to the pool and don their fins with these inserts inside on the first day of class! Also, as mentioned before, swim fins that can be purchased at sporting goods stores for lap swimming and freediving fins are not good substitutes for scuba fins. Finally, I can’t help mentioning: never unbuckle the little quick-release buckles on your fin straps- always just loosen and tighten the straps, or just stretch them over your foot if they’re rubber. If you open the buckles, 9 times out of 10 they’ll get sand or something in them and be impossible to re-buckle.

GET IN THE LOOP:  Finally, whether you get splits or paddles, one feature that I REALLY recommend is looking for fins with straps that have a little loop molded into them that you can hook a finger through. You can live without this feature, and it’s still not very common on a lot of manufacturer’s fins, but all other things being equal, if you see a pair with the loop straps they’re MUCH easier to get on and off than the straps with just a little tab on them.  Along the same lines, if you break a strap and have to get a universal replacement, try to look for one with a loop.

What do I use?

Apollo Bio-Fin Pro, the plain ones with the plain rubber (loop!) straps. These are black, and they don’t float; if you use them, mark them with a brightly colored gear marking paint pen in case you drop them!

Perfectly good paddle fins can be had in the neighborhood of $40 and up, to give you an idea of a reasonable price. Apollo Bio-Fin Pro fins can be found for about $150, and they’re virtually indestructible, so used ones, which can be had for about $100 on ebay, scubaboard.com classifieds, etc. are a great deal if you already know which size you need.

No matter where you’ll be buying your gear, Remember to always do Google Products (Froogle) search and / or a pricegrabber.com search to get a rough idea of what a reasonable price is on items you’re considering, to avoid being scalped by any unscrupulous retailers. There are many great reasons to purchase your gear locally if you can, and I encourage you to find a reputable local dealer when available, and to use them when they stock the items you want. However, although in-store advice is well worth a few extra bucks, there’s no excuse for going into a shop without knowing what the going internet rate on an item is. To give you an idea of how much you can be ripped off by the wrong retailers, I frequently see people selling worn-out gear used online for a price they think is a great bargain (i.e. less than half of what they originally paid for it new) when in fact a knowledgeable shopper can find the same exact gear BRAND NEW for a lower price than they’re trying to sell it for used.

If you’ve found this tutorial helpful, please consider making a small donation! Thanks and happy diving!

Choosing your starting gear – Part 2: Snorkels

Snorkels

GENERAL CONSIDERATIONS: Snorkels are not the pieces of gear that people most often lose sleep at night over the choice of, and rightly so. Simple is better. A good snorkel should not exceed 15″ in length, to avoid dead air space (so that you won’t be breathing in so much of the air you just breathed out). If the end is circular, you should be able to get your thumb into it. If the end is elliptical, that’s fine; if the end is covered in a gee-gaw that is supposed to keep water out of the top, (a) look for a cheaper, less complicated snorkel and (b) give your scuba instructor a slap on the wrist for not teaching you to clear a snorkel! It’s easy. Some snorkels have purge valves; they’re o.k. but completely unnecessary. Some snorkels also have a flexible bit that lets the mouthpiece hang out of your way further- although this is as usual just one more piece where something can break, I have to admit I kind of like it in this case, although again you won’t miss it if you can still find a plain J-shaped plastic tube for $5 anywhere these days.

THE CLIP ISSUE: One other thing that all snorkels come with these days is a little hard plastic clips that allow you to quickly clip them on and off of your mask. If you keep your mask tucked in the foot pocket of your fin with the snorkel hanging out, rather than in its little enormous plastic vault that it comes with, there’s no reason to ever remove your snorkel anyway, and unfortunately, these little clips are very good at coming off of your mask while you’re diving. I know because I find snorkels on the bottom of the ocean, with the little clips still attached, all the time. While I hate to talk myself out of a great supply of free snorkels, I’d advise you to spend a buck on a snorkel keeper, a little rubber, neoprene, or soft plastic double-loop that goes over your snorkel. It takes a moment longer to put on the first time, but then it stays there. My favorite by far are the stretchy rubber ones because they stay on the best; they also make great makeshift secondary reg holders for rental gear- just loop one end through the other and over a D-ring on your B.C., and there you go. I like to keep a couple of extra rubber ones around for this purpose.

PUTTING THEM ON: When attaching your snorkel, a few tips for the rusty or uninitiated. 1 – Put the snorkel outside of the mask strap, not inside. 2 – Snorkel on the left, regulators on the right. 3 – ideally you want your snorkel as far back as it can go on the mask strap, just before the strap widens out or splits. For the height of the keeper, you just want the mouthpiece to line up with your pie-hole.

What do I use?

Genesis Surf, although any simple snorkel will do great.  Great snorkels can be had for as little as $10, and paying more than $25 for one is unreasonable.

No matter where you’ll be buying your gear, Remember to always do Google Products (Froogle) search and / or a pricegrabber.com search to get a rough idea of what a reasonable price is on items you’re considering, to avoid being scalped by any unscrupulous retailers. There are many great reasons to purchase your gear locally if you can, and I encourage you to find a reputable local dealer when available, and to use them when they stock the items you want. However, although in-store advice is well worth a few extra bucks, there’s no excuse for going into a shop without knowing what the going internet rate on an item is. To give you an idea of how much you can be ripped off by the wrong retailers, I frequently see people selling worn-out gear used online for a price they think is a great bargain (i.e. less than half of what they originally paid for it new) when in fact a knowledgeable shopper can find the same exact gear BRAND NEW for a lower price than they’re trying to sell it for used.

If you’ve found this tutorial helpful, please consider making a small donation! Thanks and happy diving!