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Posts posted by frogfish

  1. Jean,


    I used to have bad dreams about a sequence of events and contingencies like yours. It can happen all to easily, all too fast. I just recently (about five weeks ago) became an ex-boat owner. I'd owned my 28-ft sloop since 1984, and had many great times. I also dropped a lot of $$ over the years. They say the two best days one ever has while owning a boat are the first and the last, and I think they're right.



  2. I didn't even know that Hitachi and Seagate were already selling 500 Gb and 750 Gb drives. Perhaps the best part of this news is that once this puppy comes out, 500 Gb drives will become the new standard that we can all afford.


    Of course, I've consistently under-estimated my real storage requirements, like almost everyone else. Moving to the D2X didn't help. But I can't help but think that a pair of 750 Gb drives wouldn't at least keep me going for another year or two.


    Terabyte Drive



  3. I have the Halycon stainless steel and aluminum backplates, an Eclipse (30 lb.) wing (which takes the Halcyon single-tank adaptor) and an older "Pioneer" (27 lb.) wing which can be used without the STA, simple webbing (DIR-style) harnesses on both. On both harnesses, I have two small square pockets on waist band which I have made by someone here in Bali (they are much smaller than the Halcyon pocket) - one carries a spare mask, the other an emergency strobe, dye pack, rolled up hat with neck flap and a reef hook.


    I prefer the stainless steel BP and also like the Eclipse with STA better than the the STA-less Pioneer. Without the STA, the tank sits too close to the BP (and the back of my head), my hose routing doesn't work as well, etc.


    The stainless BP is mainly for local diving here in Bali and/or trips originating here. If I have to fly with dive gear, then I take the aluminum backplate. For doubles diving, which I do very rarely, I borrow or rent a double-tank wing and use it with either backplate, usually the SS.


    In practice, the aluminum BP, the STA and the Eclipse wing spend a lot of time on boats or in transit without me. Since I've done two trips on the Seven Seas this year and will do a couple more over October/November, it has made sense this year to leave a full set of dive gear (BP and wing, fins, reg set, etc.) on board, minimizing the amount of gear I have to shlep via small planes.


    Living in Indonesia, it isn't really practical for me to source dive gear from small independent manufacturers in the US like Oxycheq or FredT, so I'm not in any position to compare their products iwth Halycon. I basically like Halcyon equipment, but the critical factor for me is that there is a good Halcyon wholesale distributor nearby in Singapore, my friend Avandy at BIDP is a dealer so I can get some stuff here in Bali (though I usually have to bring anything in myself from Singapore), and Halycon gear is also available from dealers in Hong Kong and the Philippines. (Once, when I had a minor problem with a Halcyon wing, Halycon airshipped a new wing to me within a few days.) However, I had to pay duty on that.) If I lived in CA or FL, it might be different.


    (The last conventional BC I owned was a Seaquest Balance too.)




    P.S. Weights. In warm water, with the stainless BP and a 3-mil wetsuit, I only need a couple of kg on a belt under the harness. With a 5 mil, I add two more kg in trim pockets on the lower tank camband. With the AL BP and a 3 mil, I will have 2 kg in trim pockets on the tank cambands and 2 or 3 kg on a belt. With a 5 mil, I carry 4 kg on the belt. Diving doubles, it depends on the size and weight of the tanks, of course, but if they're steel, then I won't need any extra weight.

  4. Lots of good points made here. II definitely feel that, in the age of PADI, dive certifications in themselves mean very little. Just having a PADI basic open water card doesn't really qualify anyone even to dive, as far as I'm concerned. But I also know a lot of very experienced, highly skilled divers who have no qualification beyond basic open water.


    Max Gibbs, one of the world's great authorities on fish id's, a very good underwater photographer for many years now, who normally does 500+ dives (mostly on liveaboards) a year (when he's not writing another fish book), finally had to get Larry Smith to give him a PADI "Advanced Diver" card (I think they call it something else now) because petty-minded American and Australian divemasters/cruise directors on some liveaboards - people with fewer total lifetime dives than Max normally does in a year) were insisting that he wasn't qualified to go below 24 meters with only a basic open water diver card. That's nuts.


    And I've also run into people with PADI divemaster cards with less than 100 dives under the belts, who had terrible buoyancy control and in-water skills. The PADI organization has a lot to answer for. There is no good answer to Alex's question, and the main reason (in my view) is that PADI has rendered certification levels meaningless. And, in an extension of Gresham's Law (bad money drives out good), PADI's driving standards down has effectively forced the other certification organizations to dilute, dumb-down and make their own courses easier.


    Mine? CMAS *; PADI AOW, Rescue Diver, Nitrox; IANTD Deep Air.


    I'd very much like to take the DIR course if it's ever offered within 1000 miles of where I am.



  5. John,


    Gee, I had the distinct impression that whenever you were comped on a dive trip you always still ended up 'paying your way'.


    All I really want to know is whether we will be able to read about the GLUG Red Sea charter in your magazine soon?


    Seriously, gay/lesbian dive groups are springing up all over. There have been numerous groups chartering liveaboards here in Indonesia and in Thailand in recent years, and of course in the Caribbean and Red Sea as well.


    The industry here in the Indo-Pacific seems to be becoming more aware of this growing market segment and their interests.



  6. I really wanted stay out of this one, hoping this thread would just die away, but like the maggoty-fleshed corpse of the undead in some film by George Romero on late night cable, it keeps crawling out of its crypt and dragging its slimy tail across the floor. Those of you who know me already know I find even the idea of photographic competitions repellent, ethically and aesthetically. This too.


    The question" "What is the best dive destination in the world" is either insane, or meaningless, but probably both.


    It may be fair to ask who has run the fastest mile, written the longest book, or who eaten the most hot dogs in a one-hour sitting, though personally I cannot imagine why anyone would find such questions interesting or important.


    But asking "What is the best symphony ever written?" or "what is the greatest painting?" is to utter nonsense. What is the best novel ever written? Who is the most beautiful woman in the world? Who was the world's best pianist? Is there one kind of flower in the world prettier than all others?


    What kind of person asks questions like this? Or would try to answer them? (I mean, of course, who other than Donald Trump, Britney Spears, their staffs or pathetic wannabes.)


    Tell me that you loved a sunset you once saw from a cliff above the California coast at the end of a magical day, a view you once had of wildflowers growing on a hillside in spring, or the memory of the sight of a whale breaching in the morning sun. Tell me there is a poem by Gerard Manley Hopkins that sends chills down your spine, or a painting by Caravagio that tears your heart, or a certain violin concerto that, for you, is a kind of rapture.


    I'd be happy to hear about any experience underwater that you consider, as an experience, to be among the best dives in your life (so far). If you happen to be a person who has dived many places in the world, and whose judgment and experience I've come to respect, then I will pay a lot of attention to what you say.


    But as to making ranked lists, or to even try to discuss the "best " dive destination (or the best anything) in the world - please spare me.



  7. Oh, you ex-PHers - those bands are tres kinky! "Softer than a sting ray's underside?" Be still my heart! But wouldn't studs and extra zippers make a dry suit less efficient?


    What about opening a bar (London? The Bay Area?) called something like "Terminal Phase Males" - the interior lighting would simulat water ripples, there would be lots of ntensely saturated ightbox images of sex-changing parrotfishes and the like, while the staff could wear uniforms designed by John Bantin.


    But perhaps this isn't exactly the direction Eric intended this thread to be going. Let me refocus by saying that if I ever get a dry suit, then I will definitely want to get Apollo bio-seals. These sound so good I almost wish I weren't a complete warm-water wimp.



  8. Yes, this is very good news.


    I take Alex's point above, but beyond reducing the danger to Sipadan's already somewhat battered reefs, by backing down from this unnecessary construction of a clubhouse and restaurant (immediately after expelling the resorts on the pretext of reducing environmental damage) also averts what could have been a fatal blow to the credibility of the Sabah and national government of Malaysia with respect to protection of marine environments.



  9. I'll weigh in by saying first that I think this depends on what you expect the encounter distance to be, or what you intend to achieve. Manta dives rarely happen in gin clear waters, so I would assume you will be trying to shoot from as close as possible. But n a reasonably close encounter with something as big as a manta, unless you want to shoot details of specific parts of the manta anatomy, I cannot imagine that the 10.5 could ever be "too wide"




    10.5 Manta (and not that close), in Komodo last year



  10. Will the 105 VR fit in the 60 mm port (with an extension ring) that that doesn't have a focus gear, or the 105 mm flat port without a focus gear?


    I somehow seem to have acquired three Subal macro ports - two for the old 105 mm (one with and one without focus gear) plus a 60 mm port (w/o gear). I would really hate to have to buy another one.



  11. I had the good fortune to be on the same R4 trip with David and Jen that Todd was. Most of their rigs were film, but they had two digitals - I think one was a D100, forget what the other one was.


    At least for NatGeo assignments, they shoot digital raw, but they don't do anything to the files themselves. The raw files are treated like negatives - it all gets sent back to the trolls on M Street.


    I hope that I'm not speaking out-of-turn, but I also recall that they weren't 100% happy with that arrangement. When you or I pull a raw file of one of our own images into ACR or another native converter, we have a subjective memory of what the colors in the original scene actually looked like, and we also have a good sense of what elements in that image would be good neutral greys or non-specular whites to use as anchors for adjusting white balance.


    That is not the case when a photo editor encounters a raw file without any context or knowledge of what the colors of the actual subject and scene looked like, particularly underwater images where the default settings the camera selected for an accompanying jpeg (if there is one) might be wildly off. There had been at least one problem with a digital raw image they had submitted for a previous article being converted by a photo editor who made some erroneous assumptions about what the colors really looked like.



  12. After this discussion between Kriptap and Frogfish, I think the most interesting part is the wide variety of conservative to not so conservative models out there.  My LDS sells a lot of Oceanics.  They are a big shop, and thus many people here in San Jose have these computers.  We are not seeing more people going into DCS, or at least nobody is reporting them.  ...  At the end of the day, the question is which computer can we trust?  This is after all part of life support.


    Interesting point in an interesting discussion, one in which I hope nobody has been offended. I don't think that anyone here is saying that, say, Oceanic or Cochrane computers are intrinsically unsafe. Nobody intentionally designs unsafe decompression algorithms or manufactures unsafe dive computers, but there are clearly different ideas in the industry and among consumers about what constitutes "conservative enough".


    The venerable US Navy Tables (ancestral to PADI's) were never designed to prevent DCS in all combat divers all of the time; the objective was to reduce the incidence of DCS in a population of young, fit, carefully screened and trained individuals to an "acceptable" level. An expected DCS incidence ratio of one hit in 500 dives might look reasonably safe to some people in certain situations, but not others. How comfortable should someone with more than 999 dives be with a more conservative algorithm expected to reduce the hit ratio to only 1 in 1000 dives? Or 1 in 2000?


    Dive computer or decompression algorithm cannot directly measure dissolved and gaseous phase nitrogen in our tissues, nor can they take variations in susceptibility to DCS into consideration. These are mathematical models. Some of us are persuaded that RGBM can better model the actual physical processes involved than a Haldane-based algorithm, but that doesn't make it 100% safe. We all know things that are supposedly risk factors for individuals - age, lack of cardiovascular fitness, % body fat, alcohol consumption, dehydration, lack of rest, etc. And I suspect most of us also know someone like Drew, who is considerably younger, fitter, thinner than I am, and who doesn't drink, but who has taken an "undeserved" hit doing a dive with the same kind of dive profile that I have done many times.


    We all have to decide what level of risk is appropriate for us, but also keep in mind others who rely on our judgment or may be tempted to follow our example. Kriptak made it clear in his 2nd post in this thread that he wasn't advocating that anyone else play with the EANX % setting on their computer to increase bottom time. But I did want to say loud and clear to others reading this that there are divers here who would consider this an unsafe practice. I have a friend who dives pure DIR rules. He believes that I'm crazy because I do things like dive beyond 30 meters on air instead of trimix, do more than two dives a day, and do dives that require mandatory deco stops without using twin tanks and deco gas, following the rule of thirds, etc.


    LChan mentioned diving in the San Francisco Bay Area. I could be wrong, but it's my impression that recreational diving there is often limited to two dives a day, rarely extends over more than two or three sequential days, and that generous or at least adequate surface intervals are the norm, if only to get warm.


    As the discussion here has highlighted, the difference between RGBM (modified or full-up) and Buhlmann-based algorithms in terms of bottom time and/or deco stop time is most noticeable on multiple day repetitive diving and when surface intervals are cut short.


    This, of course, is the kind of diving we are most likely to be doing on trips on a live-aboard or at a full-out dive-oriented resort, especially in the tropics, and some of those liveaboards will be operating in remote areas of the world far from hyperbaric facilities.


    Personally, I don't really think it matters much what computer is used for simple 2 or 3 tanks a day recreational diving over only one or two days. But I think it may matter a lot on a liveaboard when people are doing 3, 4, and even 5 dives a day for up to twelve days, or even longer. I'm afraid that these situations - when having a computer that is sensitive to the heightened DCS risks posed by repetitive multiple-day diving is most important - are also likely to be the situations where some divers will be tempted to cut corners with N2 % settings or else intentionally select a dive computer because it gives him or her more bottom time than other computers rather than for maximal safety. If this discussion only serves to make anyone in this situation think twice before buying a computer because it is generous with bottom time, then it will have been well worthwhile.



  13. O Lorbert, while 4 is 4 universally, empat is 4 but ampat is an acceptable way of spelling 4 in bahasa melayu or Indonesia. Afterall they only really reformed Bahasa to a standard form in 1972. So some  schleps missed the class. Blame the Sri Vijayas for spreading it way back when. I mean, Hakka is so much more eloquent.


    Ampat, ok, but Amphat - I have to say amphatically "no". But, on the other hand, who really gives a fak-fak? How's Phuket these days?



  14. Frogfish I think you missed what I said, so I'll say it again slowly "What's worse is I have a Sunnto D9 but have it set to 27% Nitrox which is still a little behind my Oceanic on air!" I use an oceanic on air...... the Sunnto is on 27% so I can use it or it would permanently be bent, so yes do avoid the "s" word and read the post. ;)


    If I misunderstood what you wrote, then my deepest apologies, but I don't think I have. You've said (twice) that you are have set your D9 to 27% Nitrox while your Oceanic computer is set on air. I assume that means you are diving on air (=EANX21, not EANX27) and that by "behind" you mean that the Suunto set on EANX27 still gives you less bottom time and/or requiresa longer decompression stops than the Oceanic set on air does.


    I can only interpret your explanation that you dive with the Suunto set to EANX27 while diving on air "so I can use it or it would be permanently bent" to mean that the Suunto computer - not you - would be permanently "bent" (i.e., that it would lock you out) because you've chosen to follow the the least conservative of your two computers rather than adhering to the Suunto's decompression limits and instructions.


    Most of the people I dive with would adhere to the principle that, when multiple computers are used, one should follow the most conservative computer regarding no-stop times, deco stops, etc. not the least.


    If I understand you correctly, what you're doing here is the same as diving with two computers, following the least conservative profile of the two, and then putting the computer that is still "in deco" when you come up back in the water on 4 meters of line and hanging it over the side of the boat so it can "decompress" while you have a hot shower. If so, then I'm afraid the "s" word still does apply, as might the reference to Darwin. If I've misunderstood what you're saying, then don't be angry, just point out how I've misconstrued your meaning.



  15. Hey John

    Bruce ... shook his fist at me when I told him that the record of RGBM having a clean record was not so clean because I took a hit diving within RGBM in PNG. Then a few others came to pour more rain on the RGBM party.

    However, for dive guides and professionals, the computer quagmire is a very real dilemma. I mean, someone comes with a clean computer for 1 -2 weeks and leaves loaded, expecting the guide to stay with them or worse the company expects them to stay with the clients.

    Now many dive ops switch DMs so they don't dive 4 dives a day 350 a year. But there are many who don't.

    As for the EAN % switchers, I wish you all the best of luck and hope you stay out of the can. However, please let me know which trips you're on so I can avoid the same boat. I like having not to stop a trip for medical emergencies.


    But Drew, didn't you hit the hot tub (or have a hot shower) that time?


    By now I think we all know that isn't such a great idea, but it wasn't that long ago that most of the Aggressor fleet actually had hot tubs that people were jumping into right after coming in from diving.


    You're absolutely right about dive guides. There are lots of boats that do same day turn-arounds, which doesn't allow the diving personnel much off-time for off-gassing. My friends on a boat here just had a customer (Russian nationality) who decided to take his newly certified 12-year old son on a bounce to 60 meters. Obviously without telling the dive master ahead of time, who sensibly did not follow them all the way down. Both of them were banned from diving the rest of the trip, but it was almost over. This was in Komodo, where there is no chamber - the closest is Bali, almost a two hour flight.


    There is a line of thinking that the only reason more dive guides don't get hit is that beyond a certain point, repetitive diving can lead to a higher resistance to DCI, the result of a reduction in microbubble nuclei. Wienke has written about this.



  16. John,


    I'm duly impressed (by what Wienke said when he shook your hand), but hardly surprised). I'm sure everybody here knows (or at least they should know) that the side-by-side equipment comparisons you've run as technical editor at Diver magazine are the best, and absolutely unique in the industry. How many diving publications, other than yours, have ever run a negative review or evaluation of any piece of dive equipment, particularly when it is an advertiser?


    I was also interested to see that you cited Pyle and included an explanation of ad hoc deep stops at the end of your excellent comparison test of computers from the March 2006 Diver issue.


    Since what I've just posted above could be read as advocating that users of Haldane computers practice ad hoc deep stops (which it is, and I do), it might be worthwhile printing Bruce Wienke's remarks in 2003 urging caution about the practice. This is from Another scuba-related website:




    The business of "P/1.6", "halving", and "gradient factor" rules for juxta-positioning deep stops (first and following afterward) are all ad hoc measures imposed on Haldane deco. Sometimes they work for very limited diving and ranges, but in general they are without real physical basis. They are attempts to get a dissolved gas (only) algorithm (Haldane M-values) to mock up bubble dynamics. And such rules are not self consistent for diving. They are also risky when they miss requisite deeper stops, but give shorter overall deco in the shallow zone.


    They are a poor way to mock phase dynamics when dual phase tables, meters, and software are now available to do this self-consistently over a whole dive profile.


    Diver, beware.


    Bruce Wienke, Program Manager Computational Physics, C & C Dive Team


    In another post, however, Wienke does make it clear that he endorses the idea of short ad hoc deep stops for all recreational no deco stop diving:


    "Deep stops for recreational no-deco diving are safety stops, and the 1/2 rule holds up fine in this regime. This is a coupled rule for the new NAUI Rec Tables and it has been correlated in RGBM and by Bennett at DAN. Plus Marroni. Plus others. It extends to ALL recreational Tables, RGBM, Navy, etc that we use. The rule is "one minute at half the bottom depth" Remember, this is for recreational, no-deco diving.."


    Those of us who mainly dive on coral reefs usually end up doing more than one minute at half the max depth as part of our normal multi-level ascent anyway.



  17. Agree with Mike, Sunnto are nice looking computers but crap on time, day after day the first up the line are the Sunnto users while the rest carry on diving, Sunnto have to be the most conservative computer on the market and for this reason I never recommend them to divers, Sunnto if your listening that's 100's per year in sales you miss out on. What's worse is I have a Sunnto D9 but have it set to 27% Nitrox which is still a little behind my Oceanic on air!


    Following on Drew's comment above, the RGBM algorithm used in newer Suunto (and other) computers is very different from the Buhlmann-based "Haldane" models used in the most other dive computers. Calling it "more conservative" may be correct (if misleading), but complaining that it "punishes" the diver doing repetitive dives misses the point. As for intentionally setting the computer to a nitrogen percentage less than the actual N2 content of the breathing gas in order to avoid doing deco stops you should do, thus overriding the computer's best efforts to keep you alive ... that strikes me as (avoiding the "S" word) ... a potential example of Darwinism at work in our species and the modern world.


    Buhlmann models assume that all nitrogen in body tissues is in solution. The reality is that nitrogen in our bodies during a dive exists in solution and in free gaseous phase, namely bubbles. The modified version of the "Reduced Gradient Bubble Model" (RGBM) algorithm used in newer Suunto computers, developed by Dr. Bruce Weinke at Los Alamos National Laboratory, takes phase transitions between nitrogen in solution and gaseous form into consideration, which Haldane models cannot do.


    It's not that RGBM "punishes" repetitive dives or short surface intervals. Rather, Buhlmann models fail to take into account the additional risks of repetitive multiple-day repetitive diving, inadequate surface intervals, and/or 'bad' profiles (saw-tooth, bounce, and reversed profile dives).


    Setting a RGBM computer to 27% nitrox while diving on air to avoid having to make decompresion stops is asking for trouble, in my opinion, and may be riskier than just using an older and cruder Buhlmann-based computer. As someone in this thread has already asked [RD: it was John Bantin], what's wrong with just doing the stops? (Or to put it another way, what is it that you really like about decompression sickness?)


    If you prefer the additional risk of doing repetitive dives with a Buhlmann computer (or if you're one of those divers who think driving your computer all the way to the no-dec stop time edge on every dive is smart diving), then I'd have to ask why you bought one of the very few RGBM computers that anyone makes in the first place? There are still plenty of aggressive dive-at-your-own-peril computers for sale in every dive shop, though Mares and other manufacturers have also released new RGBM-based computers or are about to do so. Something to do with those pesky lawsuits from the estates of dead divers.


    None of this is meant to suggest that RGBM is perfect or that it guarantees you will not take a hit. I do think RGBM is superior (and safer) than Buhlmann models, but there are cases where divers using RGBM have taken DCS hits, though most if not all were technical divers doing very deep dives with rebreathers and/or exotic gas mixes.


    I should also make it clear that even though I believe RGBM is safer, I use two DiveRite computers (Duo and a Nitek Plus), both Buhlmann-based - I carry both of them on every dive. They both still work and don't require replacement yet. I also have reliability issues with Suunto due to bad experiences with a Solution Nitrox that I owned years ago. But I am aware of the limitations of the Buhlmann algorithms and do what I can to compensate. For example, deep stops (starting at half the difference between the max depth and first deco-stop depth, or half the maximum depth on no-stop dives), avoiding bad profiles, and never driving the computers to the edge, particularly for multiple day repetitive diving (for example, on a liveaboard).


    By not driving the computer to the edge, I don't mean that I limit my bottom times more than you. It means that I do my stops, and I take extra time on the safety stop on any dive that has pushed near or beyond the no-stop limits.


    It would be interesting if someone here started a poll - who has ever taken a hit, or more than one, were they using a computer at the time, what compuer (and what decompression model), what gas, and was the dive part of a sequence of repetitive dives on multiple days.




    P.S. RGBM isn't the only non-Haldane decompression model around, but it is the probably the best, and the only one (to my knowledge) that has been implemented on a commercial dive computer suitable for recreational diving. Other non-Haldane models include the Canadian Series model (implemented in the DCIEM Kidd-Stubbs dive tables), the EL model developed by the US Navy and implemented as a military computer for combat divers, the Slab model developed by Dr. Tom Hennessey for the British Sub-Aqua Club (implemented on tables), and the Varying Permeability Model (aka Tiny Bubble Model), and its successor, VPM, developed by Yount and Hoffmann at the University of Hawaii, implemented on tables and in software, which is generally viewed as the progenitor of Wienke's RGBM model.


    Jolie Bookspan's excellent "Diving Physiology in Plain English" has a short discussion of the non-Haldane models.


    Wienke has a book about RGBM out..


    Wienke's book on Amazon


    ... and it is also covered in his Basic Diving Physics and his textbook on decompression theory and Technical Diving in Depth.


    There's also a very interesting piece about Deep Stops by Richard Pyle, the University of Hawaii/Bishop Museum ichthyologist who independently discovered the value of deep stops about ten years before Wienke uncovered the theory behind them.


    Richard Pyle on Deep Stops

  18. Does anybody know of any organized dive trips to Raja Amphat in january or feb/o7?


    There are lots of boats operating during this period. November through March is the best season for Raja Empat, and not a great time in Komodo, so a lot of boats relocate to the Banda Sea/R4 area during this time. Now would be the time to book, by the way, if it isn't already too late, at least for the better boats. Some of these trips are sold out a year in advance.


    Let me also "amphatically" urge everyone to note the spelling of the name of the place. "Empat" means "four", and rajas were of course kings in Hindu-influenced cultures including pre- and non-Islamic Indonesia. (Islamic local rulers were - and are - sultans.) So "Raja Empat" means "Four Kings". The name is a reference to the four biggest islands in the grouping off the western tip of the bird's head of Western Papua. And hence the common shorthand reference "R4".


    As to the debate over liveaboard versus resorts, I think some people have said some silly things here. I can understand people wanting to support Max, who I understand runs an excellent dive operation. It isn't necessary to slag liveaboard operators and throw out unsubstantiated and misinformed criticisms of their knowledge of dive sites. R4 is a big place. It would be surprising to me if Max and his divemasters were not the best informed about the dive sites in the area around his resort. But that represents a fairly small part of the overall area.


    There are several liveaboard operators who are very knowledgeable indeed about the whole area. Of course, one of the biggest attractions of R4 outside the area close to Max's resort is that it is possible to do exploratory dives on new sites which have not been dived before or only rarely, and are not well known.



  19. It isn't necessary for the housing or attached strobes etc. to have magnets in them for this to be a problem. Any electric circuit (for example, the ones between your camera and strobes) will create magnetic fields. (Volcanic sand is made up of ash and/or broken down basalt, which is itself a composite rock made up of tiny crystals of feldspar, pyroxene, and olivine. The problem for us are black iron sulfides and pyrites that also make up part of the ash or basalt, and which are attracted to magnetic fields.)


    And one doesn't avoid the risk by never laying the camera gear down on black sand. The biggest danger, IMHO, comes when one cannot resist the desire to shoot in shallow water affected by surge and surf, which pick up the volcanic sand and suspend it in the water column. For instance, shooting flame file shells or boxer crabs under the rocks in the shallows at Tulamben (or any dive at nearby Seraya when there are big waves).


    It's a good idea to check and clean all accessible o-rings (body, port, and battery compartment o-rings on strobes, etc.), o-ring grooves after any dive on black sand, particularly if there was exposure to silty waters churned up by surf or whatever. And keep in mind that the tiny o-rings around buttons and controls are also a potential threat.



  20. Wrap the housing in a very wet towel. If in a car, put the whole thing in a big plastic bag. On a boat, just keep dumping more water on the towel. Then do a good rinse in fresh water when you're back at base or the mother ship.


    The primary objective is to keep salt water from drying on the camera (especially through connectors) and block the formation of salt crystals. As long as the housing stays wet, that won't happen.



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