Holy shark bait!
September 29th, 2007 Filed Under Uncategorized
Whoa! Apparently this pic is not doctored and is the real thing. I guess this shark is in the mood for a banana. I found a link to it at http://scubadiving.gadling.com. Here is the post URL:
http://scubadiving.gadling.com/2007/07/05/reason-451-why-im-afraid-of-the-ocean/
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Blue screen of death
September 29th, 2007 Filed Under Video clips
This is a Sun commercial against Microsoft that was apparently banned from TV. I found it on http://www.scubaherald.com/.
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Self-reliance
September 28th, 2007 Filed Under Article
I like the idea of being more self sufficient in the water so I can rely less upon whomever I have for a buddy. Not that I want to dive completely solo, it is just that even with a buddy you may very well be effectively diving solo. Here is why:
- One of the reasons for having is buddy is in the event of an out of air situation. That means the buddy is carrying my emergency air supply. What if they don’t manage their gas supply well enough to leave a little extra for me? What if I am bigger than the buddy and I suck down their tank? What if they are ahead of me and I can’t catch them on one breath of air?
- Counting on a buddy to help me means relying upon them to have the skills and the mindset to do it. To me, that means everyone should aim to be at least rescue trained.
- In the past I have gone on dive charters alone and been assigned an “insta-buddy” wherein the boat divemaster says everyone needs a buddy and pairs up buddy-less divers. How much can I rely upon this other person?
I remember one insta-buddy incident in particular. I was on a dive charter in the Turks and Caicos islands and I got assigned an insta-buddy on the boat. After we jumped in to the water, we descended and he took off. He never looked back. I followed for a bit, but when I realized I couldn’t catch him, I gave up and just had a nice solo dive. Back on the boat I didn’t bother saying anything to him because after seeing what kind of buddy he was I felt safer diving solo. I had my underwater housing for my 35 mm camera and a big strobe unit to drag around, so I liked the idea of just cruising around and snapping some pics. Of course this brings up the issue of having mutual dive objectives, so my bad for not discussing them…but he should not have taken off like that. The next dive was the same thing. We descended from the surface over the wall. He flips heads down and starts finning hard straight down along the wall. I thought maybe he saw something, so I start following. At 80 feet I stopped and watched him disappear below me. I ascended a bit and had a nice solo wall dive. I would have been putting myself at risk if I were to keep up with him. He was putting me at risk by not being a buddy. Screw him.
What is involved in being more self-reliant? There is solo diving and then there is being self-reliant. Being self-reliant is part of diving solo. I want to be more self-reliant and still dive with someone else. It just means I don’t need to rely upon them as much, and if they are more self-reliant then they don’t need to rely upon me as much either. I see steps towards self sufficiency being:
- Carrying a larger primary air supply, and a redundant secondary air supply
- Proficiency in underwater skills
- Comfort underwater in dealing with a variety of conditions and incidents
- Knowing your limits
When I searched for other sources of info on the internet about solo diving, I found the objectives they list corresponds to my list.
Air supply: Under the buddy system, my buddy carries my emergency air supply. Self-reliance means I carry my own. I think this means having a larger primary tank so I have extra time to figure out how to free myself if I get tangled up in something, and it also means carrying a redundant air supply and regulator in case I have a first stage failure or go out of air. I recently purchased a 40 cf tank and regulator setup and the redundant setup, and a 130 cf for my primary. On the subject of air supply, I also believe in using nitrox in order to reduce nitrogen loading. I will sling the 40 like a deco bottle. A 40 cf tank might sound kind of big compared to the compact Spare Air units out there, but I am a big guy and therefore have a larger lung capacity. I want enough air to be able to make a slow and safe ascent from a deeper dive. I think of a Spare Air more as an escape bottle to get a few breaths in while doing a controlled emergency swimming ascent (CESA). I also have other plans for that 40 - like filling it with a richer blend of nitrox than my back gas and using it as a washout gas while ascending (once I am above the max depth for the nitrox mix).
Proficiency in underwater skills: Being able to maintain composure if someone accidentally knocks my mask loose with their fin or similar incident means extra safety for me since I won’t have the urge to bolt to the surface or grab on to a buddy. Being able to remove my BC underwater to help untangle it is important too. For me, taking the Divemaster course to re-visit the open water skills have helped give me assurance that I can handle these kinds of incidents on my own. Another skill is being able to do a free ascent while having control over the ascent so I can decide my ascent rate and where I am going to do my safety stop. Navigation is important as well; being able to make a nice underwater tour and end up back at the boat makes for a nice dive, as opposed to ending the dive with a long surface swim through kelp.
Comfort underwater in dealing with a variety of conditions and incidents: To me this means having some experience in dealing with a number of conditions, like current, kelp, low visibility, etc.
Knowing your limits: Experience will give some indication of what your comfort level is for a number of things. This is not only personal limits, but also adhere to recreational diving limits. I physically feel better after making a slower than “normal” ascent, so I like to incorporate a slow ascent in to my dive plan.
Related links:
The Buddy System Reexamined
http://cisatlantic.com/trimix/other/solo2.htm
Going Solo - The Solo Diver Debate
http://www.o2technicaldiving.com/articles/going_solo_the_solo_diving_debate/
Solo Diving the and Recreational Diver, Part 1
http://www.airheadsscuba.com/soldvrarta.pdf
Solo Diving and the Recreational Diver, Part 2
http://www.airheadsscuba.com/soldvrartb.pdf
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Safety stop
September 27th, 2007 Filed Under Uncategorized
A note on the “recommended safety stop.” We know that recreational no decompression limit (NDL) diving is “no decompression diving.” NDL diving does involve making a “safety stop.” How is a safety stop difference from a deco stop? They are both doing the same thing - letting the body deal with nitrogen bubbling out from an ascent, and to do it at a depth that keeps the bubbling under control for the body to off-gas it through the lungs for a given amount of time until enough nitrogen has been gotten rid of to make it safe to continue ascending.
Deco diving involves multiple deco stops at various depths in order to complete the ascent, and these stops are mandatory and with a glass ceiling. Even though NDL tables are set up so that a diver in trouble can bailout to the surface, whereas the deco diver has to deal with the problem at depth, I wonder if recreational divers often skip the safety stop because it is something that is recommended but not seem by them as being mandatory? My training emphasized that a safety stop is always part of the dive, so really all recreational dives are all decompression dives with a minimum 3 minute deco stop at 15 feet.
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Links to info on CO2 and diving
September 26th, 2007 Filed Under Tips
I found some links regarding carbon dioxide and how it affects us while diving:
ACCLIMATIZATION YOU DON’T WANT - CARBON DIOXIDE
http://scuba-doc.com/CO2acclim.pdf
CO2 Risk Management Summary
http://www.cisatlantic.com/trimix/AQUAcorps/mix/CO2Summary.htm
CARBON DIOXIDE AND ITS EFFECTS ON DIVING
http://www.airheadsscuba.com/archives.htm#co2
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Now diving dry
September 25th, 2007 Filed Under Uncategorized
I haven’t been too fond of my Pinnacle Arctic wetsuit and have been on the search for something that will suit me better. I was on the fence as to whether or not to go dry. Having a dry suit certainly makes things more comfortable and convenient for California diving, but cost was an issue for me. Along with the cost of the suit there is the cost of undergarments, regular seal replacements on the suit, and the chance of tearing a seal while on a trip. I found a DUI TLS SE suit on sale at a local dive shop (LDS) near me, so I pulled the trigger.
I initially bought the Pinnacle Temperate fleece undergarment for a Channel Islands live-aboard trip. I went with fleece since they are cheaper so I could kind of see what I like and don’t like in the cheaper stuff and go from there. I also brought some middleweight REI thermal long undies, a fleece shirt and a Primaloft vest to add to the Pinnacle if it wasn’t enough.
The water temps in the Channel Islands were in the mid 60’s and I was OK with the fleece with the middleweight undies. I added the Primaloft vest on one shallower dive where the temps were near 70 deg F, and I got a little warm on that dive. What I didn’t like about the fleece is it is big and bulky. It doesn’t pack very small either.
From reading online reviews and studies about undergarment thermal qualities, I decided to go for a synthetic loft insulator. Thinsulate is used in many undergarments, but in the world of outdoor clothing Thinsulate is kind of old skool stuff. I believe it is used for diving wear because some of the properties that make it less desirable for outdoor wear do not count against it as much for dry suit wear…and may even help it (like how it is heavier than other insulators and doesn’t compress as much). I wanted to go for a higher loft insulator that would compress more than Thinsulate so that when I dump air from the suit I would lose more buoyancy and therefore (hopefully) be able to pack less weight for keeping control between 15 feet and the surface. One property to a higher loft insulator is its insulating properties are more affected by the amount of air in the suit. This can be a positive or a negative depending how you look at it. It is positive in that the undergarment has a wider thermal range over which it works, the drawback is you have to put a little more air in it than a denser insulator to get good insulation.
I got bit by the dry suit bug and made a SCUBA addiction buy of the Dive Rite Primaloft jumpsuit. I then took it to San Diego for diving as well as to Monterey. Water temps were colder. Monterey was its usual 55 deg F. With the Dive Rite suit and thinner leg undies and just the medium weight shirt undie, I was fine. It also packs small and is nice and light. It is basically a sleeping bag that you wear. It is pricey, but that is dry suit diving.
Overall, I like diving dry much more than wet. My wetsuit was too cold for Monterey, and with the dry suit I am fine. On the live-aboard trip I did all but one of the dives. In the past I tended to skip more dives when diving wet…especially the night dives.
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Divemaster certification
September 25th, 2007 Filed Under Uncategorized
I recently completed the PADI Divemaster certification. I was interested in taking the course as part of my initiative to be a better diver; I liked the idea of revisiting and mastering the basic skills from Open Water (OW) class, as well as learning more of the science behind diving. Secondarily, it did sound interesting to perhaps work with a shop in assisting OW classes.
The DM course is basically four parts:
- Re-learning the basic open water skills to a higher level of critique than before, plus adding a few additional skills
- The study of the physics, physiology and other subject areas to have a better understanding of the principles behind the principles learned in the open water and other courses.
- An introduction to being a teaching assistant and run through of the programs a Divemaster can teach
- Review of some aspects of the Rescue course
The water skills part of the course focuses on the ability to have “demonstration quality” skills so that the Divemaster can demonstrate a skill taught in OW class to a student that may be having some difficulty and requiring one on one work. So all the fun skills from OW have to be reviewed and rehearsed to where the diver can not only completely nail the skill, but also do it in a way that shows the steps involved so a student can be watching underwater and be able to pick up on how the skill is performed. Some other skills are thrown in to help build task loading ability, like doing a BCD remove and replace underwater, and the lovely underwater gear exchange with a buddy while buddy breathing (the exchange of mask, BCD and fins). I found that mastering these skills gave me a higher level of comfort and confidence in the water. I also felt more self-aware…like how a golfer and bowler will become more aware of what is going on in their swing as they build experience. With more self-awareness comes the ability to better fine tune technique and equipment.
The bookwork part of the course gave me answers to why some things are they way they are. I particularly enjoyed the study of physics and physiology, like more information behind decompression theory.
A Divemaster can teach a few PADI programs, like Discover Snorkeling and Skin Diver. We took turns teaching skills from a course to the rest of the class.
The review of the rescue technique of dealing with an unresponsive diver found underwater is always good to run through while being graded by an instructor.
So did I get what I wanted out of the class? Yes - my primary objective was accomplished. Would I recommend it to someone who wants to accomplish the same objective? Absolutely.
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Another vote for Nitrox
September 24th, 2007 Filed Under Article
Fast forward several months and several dives. I have since completed the PADI Divemaster certification. I have also been doing more diving. My recent dives have been:
- The dives for the Divemaster course
- Four dives in Cabo San Lucas
- Eleven dives on a 3-day live-aboard trip in the Channel Islands (Souther California)
- Seven dives in San Diego’s “Wreck Alley”
- Two dives in Monterey, CA.
The two Monterey dives and five of the seven Wreck Alley dives were on nitrox, the other dives were on air. I have noticed that I seem to have overcome the headaches and other CO2 buildup symptoms I had before. Two of the Cabo dives were pretty strenuous. We were fighting a strong current to get back to the boat. I thought for sure the headaches and such were going to set in, but they didn’t. The Channel Islands dives all went fine as well.
Having said that, I am even a bigger supporter of nitrox for recreational diving now that I was before. I was influenced by:
- Learning more about the physiological aspects of diving from the Divemaster course
- Conversations with a tech/cave/deep dive/trimix instructor
- My own increased focus on safety after a recent motorcycle accident
- Reading stories of divers getting DCS (the bends) while diving within recreational limits
Diving withing recreational (rec) limits involves nitrogen loading. Even though rec limits are no (mandatory) decompression diving, the more nitrogen a person has in their system, then the more opportunity for them to be one of the cases of people who get DCS even while following rec diving tables. The no decompression Recreational Dive Planner (RDP) tables are a model for a large cross section of people. They are not an actual representation of what exactly is going on in any human body, let alone your body. The less nitrogen you have trying to get out of your system, and the slower the pressure change from depth to surface (i.e. a slow ascent), the less likelihood of a person getting DCS (all other things being the same…because there are other things that lead to DCS, like exertion level, being cold and hydration).
From what I have learned, using nitrox reduces the amount of nitrogen being absorbed by the body when compared to using air for the same dive profile. The less nitrogen absorbed, the easier it is to get rid of it and the less chance of DCS. Another safety feature I see is in the case of making an emergency ascent. The less nitrogen I have taken on during the dive, the less likelihood of DCS being an issue after an emergency ascent with a missed safety stop.
One thing to keep in mind with nitrox is the max operating depth (MOD) of a given nitrox mix wherein the oxygen partial pressure in the body becomes toxic. The higher the oxygen percentage, the shallower the MOD. This mean you have to have an idea of the dive profiles you’ll be doing in order to get the appropriate mix percentage.
For a given dive profile within the no deco limits of the RDP air table, nitrox will give an increased level of being conservative with regards to nitrogen loading. If a person dives to the “edge” of the nitrox RDP tables (tables adjusted for the reduced nitrogen loading of a given nitrox percentage), then the only advantage nitrox is offering is either a longer bottom time or shorter surface interval than air, and there is no increased level of conservatism for avoiding DCS since the diver is pushing the limits.
The way I have been diving is to set my computer to nitrox mode and setting the conservative variable on my computer to its max value. One issue with using the conservative factor on the computer is that I can be well within no deco limits, but because of the conservative setting on the computer I end up in deco mode with the accompanying red flags and longer no fly penalty. This recently happened while doing a nice long and slow ascent from a 95+ foot dive. The computer didn’t seem to credit me with the slower than 33 feet per minute ascent (from around 75% of my max depth), so according to the computer I had an eight minute deco obligation between 10 - 12 feet until I could finish the dive. Sure doing this “deco stop” was extra conservative and didn’t hurt, but I would rather have more control over the planning of my conservative ascent and extra safety stop time. I think from now on I will leave my computer conservative variable turned off and just end the dive well withing the no deco time limit of the gas mix I am diving. Even though my computer does not credit me for a deep stop or a slow (10 foot per minute) ascent, I will still continue to incorporate a slow ascent in to my dive plan and just know that the ascent is just another area of conservatism for me while staying within the no deco time of the computer.
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