The nuclear-weapon-looking probe—a $720-million underwater three-dimensional mapping system—was tested by Jill Heinerth at a depth of 300 feet during a 10,000-foot lateral movement. 44-yo Heinerth is considered the world's top female cave diver. I just consider her one seriously kickass person.

As much as I would like to dive with on these Sentinel rebreathers, I wouldn't get anywhere near a cave. [Daily Mail]

Scuba diving is about minimizing distraction, but you wouldn't know it from looking at a scuba diver. Ignore the standard equipment, the buoyancy compensator, the regulator that seems at first a limitation but soon a comfort, the huge tanks of compressed air. Divers are rarely content with just the essentials. Soon every spare D-ring holds a new contrivance. Lights to counteract the red-sapping murk. Spare air in cans of dubious capacity. Swinging knives that swell from utility to shark-dueling length.

So why would you want to add an iPod? Because, like all those seemingly superfluous bits of tinsel, sometimes music is exactly the tool a diver needs to make a mundane dive as otherworldly as the very first splash in the water.

H2O Audio makes iPod cases, more or less. And unless you spent first-grade science period inattentively carving carnivorous plants into your notebook, you can probably guess the mythical element in which those cases are designed to operate. (Hint: It's fire.)

Most of their product line is really more splashproof than waterproof. That's not an indictment—I strapped one of H2O Audio's Amphibx iPhone armbands around the tan biceps of a Bulgarian kiteboarding instructor in Hattaras just a week ago; a 15-foot depth rating was plenty to make him smile.

But 15 feet underwater for a scuba diver barely registers. (At 15 feet, I'm hardly done panicking about the fact that I'm breathing out of a rubber trachea.) Most recreational, consumer underwater gear will get you to around 30 feet, just under one atmosphere of hydrostatic pressure, twice the pressure one feels at sea level. If you're lucky you'll see a rating for something around 130 feet—four atmospheres, and beyond the limits of recreational diving.

That's why it's all the more impressive that H2O Audio's iDive300 works all the way down to 300 feet—over twice as deep as I've ever been, or ever will be.

That makes the iDive 300, which would just fit into an empty carton of cigarettes, useful to even those deep divers who have to take long nitrogen decompression stops, giving them something to do while resting on ascent lines, sometimes for hours, as the nitrogen leeches from their blood and is exhaled. Listening to music or watching movies is more feasible than smoking that carton, though Lord knows I've tried.

For the recreational diver, though, the iDive 300 adds more complexity. The positively buoyant case strains against its lanyard, popping into your face at inopportune times, or, as I discovered after strapping it to a D-ring low on my vest, bobbing up between your crotch, making a simple volume adjustment maneuver into an especially awkward moment for your dive buddy as he watches you probe between your legs, searching for something you can't quite grasp.

You could mitigate this by strapping weights on the iDive 300, slipping it into the pockets of a BC with weight, or lashing it onto an arm. It's a big hunk of extra equipment—large enough that every diver will want to find their own method to stash or secure it.

The iDive 300 is large because of the extra electronics onboard. This isn't just a simple Lexan case. A circuit board runs the entire length of the bottom half, wedding the standard Apple iPod connector to a set of spring-loaded controls that run along the spine like trumpet valves, as well as a chamber for the three AAA batteries necessary to power the underwater speakers—an iPod's headphone jack won't make nearly enough juice to power the integrated clip-on headphones, especially deep underwater where the pressure makes the speakers work all that much harder to vibrate.

And they're definitely speakers—silver-dollar-sized with no padding, large holes to let out the sound, connected to the case by integrated rubber cords about four feet long that can't be detached. A plastic clip is screwed on to the side of each, designed to allow the speakers to be threaded through the straps of your mask; I chose to slip them inside my hood—clips and all—once I was underwater.

I didn't have to just jump in with the cords and speakers flying, thanks to the considerate dive operator running the liveaboard dive boat off Catalina in California's Channel Islands. Instead of making us jump off the boat with all our attendant gear, one of the deck hands would lower our cameras and other delicate gear down to us on a line after we were in the water. Like all sensitive dive gear that must maintain a seal, you'd want to be very careful about catapulting in with the iDive 300 simply clipped onto your body.

If you can stomach the rollicking seas, a liveaboard is a wonderful way to dive: Full red moons oozing into a starless night; divers in dry suit underwear on the deck enjoying an adult slumber party; beautiful galley girls with long legs and marble-mouthed accents; tan, lean crew in folded down wetsuits and broad grass coolie hats; rocks jutting up along the coast painted white with gull shit; shivering divers crawling onto deck to gulp steaming coffee in full sun; tales of a boat named "Fujimo" (as in "Fuck You, Jane, I'm Moving Out"); long flies with wings like post hole diggers; a 10th-grade English teacher wearing sweatpants with "Soul Mate" stenciled on the ass.

Yet thirty divers plus crew on an 85-foot boat can make a man antsy: the pervasive overtone of urine like a seaborne nursing home; charmless, cantankerous Jimmy Buffet fans who use bravado and volume in lieu of wit, inexplicably crowning "Margaritaville" as "real music" but honking beardful laments about the corniness of Captain & Tennille; every spare inch filled with piles of gear, cameras and knives and lights and spare cans of air and extra sets of wet suits in case dry suits flood; shamefully little alcohol.

By the time I tested the iDive 300 on my second full day of diving, I was ready for a transcendent experience. The giant kelp forests were fascinating on the first day—as a tropical diver I'd never experienced anything like them—but the dives were quickly becoming unremarkable, and a cold lassitude had already begun to infect my dives. Splash in, drop to forty, watch the legally unmolestable garibaldi wave their sexy orange caudal peduncles in my face, bop around the rocks and through the kelp, rinse, repeat.

I affected an air of what I hoped would be perceived the other divers as seasoning before I jumped in with the iDive 300.

"Seems like a pain in the ass to me," I groused. "Just one more thing to break." The other divers on deck responded in kind, mostly preoccupied with their own pre-flight checklists. "Don't know why you'd want to even listen to music, really," I said to their backs.

And I was right—it was a huge pain in the ass. At least at first, with the headphone cords whipping around my head very much like kelp; the case itself trying to spring to the surface, twisting the screen of my iPhone upside down; the music at once blaring and then fading to muddled distortion as my middle ear pressure equalized. (Truth be told, I could never quite figure out why the volume would vary so much, as it would often fluctuate even while I remained at a consistent depth. There's something about the way the speakers make pressure and sound that I don't quite understand.)

Worse, the music I had chosen, a sort of dancey indie rock thing, was driving me crazy, not unlike the way favorite songs can raise hackles when you're on a road trip or slightly high.

My brief review of the controls on the surface was enough to make it possible for me to scan through my iPhone's music selection and find something else while my dive buddy patiently waited. Pressing the "Mode" button at the top flips between, well, modes. When there's an iPhone inside the iDive 300, modes are basically just different sections on the iPod and—for some reason, because you can't actually view any—Photos.

There was a weird guilt in changing my music selection at first: partially because I did not yet trust the integrity of the iDive 300, so every button press felt like an opportunity to send water flooding around my overpriced iPhone that I couldn't really afford to replace; it also felt bad to be wasting air sitting at the bottom just trying to find something to play.

But then I found the right album.

Silent Shout, by weirdo-fashion-electro brother-and-sister producers The Knife—metallic panoramic sweeps and spare dewdrop synths meted out with haunted Swedish meticulousness. In an instant my miserable one-man undersea dance party metamorphosed into an investigation of an orange, impish forest. No longer feeling as if a band were chiding me for not dancing while I was trying to keep my attention focused on not breathing water, my awareness spread wide into the water like dye, the music slipped into soundtrack, and I was parting kelp curtains to enter backlit algae cathedrals and bending my androgyne form into gloomed dells like a Miyazaki spirit.

So it works, if you get all the kinks worked out.

The iDive 300 won't be added to my standard diving rig. The less gear the better—and simply by dint of what it is, the iDive 300 adds a lot of complexity that I can't imagine will be welcome on every dive. (My second dive with the iDive 300, listening to an episode of The Bugle, was a bit of a drag. No fault of Zaltzman and Oliver, of course—they're simply an above-sea-level indulgence.)

Still, for generous divers, passing the $350 iDive 300 around for specialty dives would be a noble act. Every diver should try listening to music underwater at least once.

Sturdy, simple design

Only iPod case rated for such extreme depths

Offers an experience beyond that of most dive gear

Expensive (costs more than an iPhone)

So large that it can get in your way

Headphone cables add two more wavy bits around your mask and regulator

[H20 Audio]

John Markoff got a ride recently, and reported the craft as being interesting, even in the plankton fog of Monterey Bay, CA.

Each time the 21-foot long electric-powered submarine plunged, my loosely buckled five-point harness left me sliding out of my seat. Each time we started to ascend, I was pushed back into the seat by the acceleration...Unlike a conventional submarine, which uses ballast to plunge into the ocean depths, the Super Falcon "flies" through water. It is slightly buoyant, and it is the speed of its propeller that pushes it downward in the mirror image of the aerodynamic lift of a conventional winged aircraft.It can operate at depths up to 400 feet, has a top speed of six knots and can fly for five hours on a single battery charge.

Deep Flight is helmed by Graham Hawkes, a pioneer in deep sea exploration vehicles. Among other craft, Hawkes built the Deep Rover sub which was used to film Aliens of the Deep by James Cameron in 3D IMAX, the Mantis, which was filmed in the James Bond movie For Your Eyes Only and the Deep Flight Challenger, a winged sub built capable of reaching 37,000 feet of depth meant for Steve Fossett to break the deep diving record in.

If you're interested, John Markoff's article has a video embedded in it of the dive and a tale of the first ocean dive in the Falcon with Perkins, where they chased Hammerheads. Below, I've included a video of the Maltese Falcon coming under the Golden Gate Bridge, as well as a video of him testing his prototype Super Falcon.

[Deep Flight, NYTimes, photo by Leslie Terzian Markoff and Yachtpals]

While Liquid Image Scuba Series HD320 is a huge jump over their previous toy-mask—reaching 115 feet and capable of capturing 720p video and 5 megapixel photos—didn't anyone tell these people that one of the first rules of scuba diving is not to have objects protruding out of your personal space beyond your tank and BCD?

Apparently not. Even if the lamps get off easily in case your mask gets stuck in the coral or some underwater plant, it still looks dangerous and complicated. You can use it without lamps, but then you won't be able to use its features to its full potential. Light and color quickly disappear when you go down. In addition to that, in terms of function you will be limited to the movements of your head as far as angles go.

In other words, if you are serious about getting good video or photographs underwater, forget about gimmicks like this and get external equipment. It will be more flexible and safe. [CES Show]

The five-year, $22 million diving project is underway today, and that means six lucky divers are presently 700 feet beneath the NYC surface, trying to find where one of the bigger leaks is hiding. They're living in a 24-foot pressurized tube that includes "showers, a television and a Nerf basketball hoop," and they're breathing air that is 97.5% helium and 2.5% oxygen.

Why helium? Well, since these lucky ducks will be in a pressurized environment for an extended period of time, they need to employ what's known as "saturation diving." Long story short, this technique allows the divers to go 700 feet down, and return to their living quarters without having to worry about repeated decompression sessions. In fact, the only times they have to worry about pressure is when they first step into the tube, and when they exit it a month later.

When the divers aren't squeaking at one another in helium-speak, three of them use a diving bell to go 70 stories down, where they do things like strip out 4,000-lb. bronze pipe fittings. Their twelve hour shifts are divided up into four-hour demolition sessions, one per diver, where they each take a turn breaking concrete to get at a malfunctioning valve array. After four hours, the divers "rest" for eight hours in the murky water, before returning the the cylinder.

When they're on break, the divers can have whatever meals they like, although helium tends to dull human taste buds. Tabasco sauce is their best friend, apparently, along with jalapenos and salsa.

“They lose a lot of weight because they’re burning so many calories,” said Robert Onesti, who is running the water rescue project via Global Diving. “It’s not for everybody. It’s heavy construction work, and it’s deep.”

And when the month is up, the divers will have another week in the tube to adjust to life without helium in their lungs. [New York Times, thanks Andy!]

Head to Wired to see the whole video and read more about the KM57. [Kirby Morgan via Wired]

• There's a full-color 220x176-pixel LCD screen—which I've got to admit is quite cool, but a bit redundant, given that the lower you go, the less colors you see. Good for impressing people in a bar though, as long as they're not divers, because they'll think you're a cretin.
• It weighs 150 grams—and that's before you've even strapped the slightly fug-esque Biformeter to your wrist.
• 128MB flash memory is useful if you have your dives computerized (surprise, mine are still on paper) and wireless-upgradeable software.
• Internal temperature sensor, in-water sensor, light sensor. Yeah, nice features, but they're standard on loads of dive computers already.
• Water-resistant to 1,000 meters. All very well, but do you honestly think I'm going to go down that far, given that I don't even use a wetsuit?
• Rechargeable Li-Ion battery gives you five days on standby, 28 hours' non-stop diving.
• USB charger.
• Price is $3,000 for the steel version, and $46,000 if you want one in gold. Don't forget the only way the Sea Instrument works is if you clip it to the Biformeter, which costs $5,000.

So, to answer my question, that's a no, then. [Lind Werdelin via Luxist]

Its makers are so sure of this housing's water tightness, it will replace your Coolpix camera if there's any water leakage. It's also accessory friendly, with a 46mm port ring thread that lets you hook up accessory lenses and filters, as well as a mounting base onto which you can attach LED flash units and other cool stuff for your Coolpix.

Press Release [Fantasea]

Sometimes if you're diving really deep it might be too dark or murky to see those vital statistics. It's probably just as useful as the excellent head-up display (HUD) on the Corvette, and if the concept works well enough at 180mph, it'll certainly suffice while loitering a few hundred feet under the sea, not far from Davy Jones Locker. Take it with you on your trip to the Bahamas this winter. – Charlie White

Product Page [Oceanic, via OhGizmo]

Exomos manufactures a variety of submarines, and the one pictured here is called Proteus, which can submerge to a depth of around 60 feet. Sixteen divers can sit on the fore and aft deck and hang on while the boat submerges, and at the same time eight people can sit inside the dry cabin and see out of its huge windows. Exomos also offers single-person subs, submersibles for military use, and spy subs, too. – Charlie White

Product site [Exomos, via The Cool Hunter]